jim beam wrote:

> > On the upside, completing the downshift earlier makes it ready to
> > accelerate on short notice. All-in-all, that is one reason why I
> > prefer manual transmissions. The AT will never have enough sensors
> > until they put in one that can read my mind.
>
> you haven't driven an automatic lately.

Yeah, my friend's Prelude of mid -80s did same thing.

 

On 8 Jan 2007 06:09:03 -0800, "Dano58" <dan.dibiase@gmail.com> wrote:

>Interesting discussion I started here, I guess....!
>
>I've driven the CVT in an Audi A4 loaner and thought it was weird at
>first (as someone else noted). But it also had 'sport' settings where
>it would 'shift' thru seven 'gears'. There are more CVT's out there
>than you think - off the top of my head, I can think of the Audi (A4
>non-quattro auto models), Ford Freestyle cross-over, and Nissan Altima,
>Murano, Maxima and Versa.* I think some version of the Ford Five
>Hundred has it as well. So, they are becoming more popular.
>
>The best compromise seems to be the automated manual transmissions -
>they are a true manual trans with an automated clutch. No torque
>converter. ( http://en.wikipedia.org/wiki/Direct-Shift_Gearbox )
>Audi's DSG is commonly considered the best example, although BMW has
>one (whch regularly gets panned for poor auto shifting). Porsche may
>have one as well. I've driven the DSG and it is excellent, very fast
>shifting and a decent auto mode as well. But I still prefer a
>conventional manual transmission.
>
>For the Ody, I'm prefectly happy with an automatic.

I would really prefer that Honda would make a Volvo 240 wagon with
performance suspension and an MT, but I have pretty much given up
hope.


>*Oh, Wiki has a list of CVT equipped autos world-wide.

See my comments below. Few of these are currently available in the
US,. If you eliminate the hybrids, I think there are only about
three. Partly this is due to most CVTs being designed for small
engines.

Most CVT designs seem to be reliable and the efficiency improvement is
significant compared to conventional ATs. I really think that the
test drive turns off a lot of buyers because it is so unconventional.
Honda is apparently selling a "7-speed CVT" - talk about an oxymoron.
This is a sure sign that buyers are turned off by normal CVT
operation. Hybrids may be the thing that brings CVTs out of the
closet.

See comments below.

> * Audi A4 2.0/1.8T/2.4/3.0/2.5 TDI
> * Audi A6 2.0/1.8T/2.4/3.0/2.5 TDI
> * Dodge Caliber
> * Fiat Punto 1.2 L
> * Ford Escape Hybrid 2.3 L 4 cyl
> * Ford Five Hundred 3.0 L 6 cyl
> * Ford Focus C-MAX 1.6 L TDCi 110 PS
> * Ford Freestyle 3.0 L 6 cyl
> * Honda Civic HX 1.7 L 4 cyl
> * Honda Civic Hybrid 1.3 L 4 cyl

The only US Civic currently offered with a CVT is the Hybrid.

> * Honda City 1.5 L

I haven't heard of a Honda City in a long, long time. Are they still
sold?

> * Honda HR-V 1.6 L

Never sold in US.

> * Honda Insight 1.0 L 3 cyl

Discontinued - will probably be replaced.


> * Honda Jazz 1.4L / Honda Fit 1.3 L/1.5 L

No CVT in US market.

> * Hyundai Azera 3.8 Lambda
> * Hyundai Sonata 3.3 Lambda
> * Jeep Compass 2.4 L
> * Lexus GS450h 3.5 L 6 cyl
> * Lexus RX400h 3.3 L 6 cyl
> * Mercedes-Benz A-Class
>
> * Mercedes-Benz B-Class
> * Mercury Montego 3.0 L 6 cyl
> * Microcar MC1/MC2 505cc 2 cyl diesel or petrol
> * Microcar Virgo 505cc 2 cyl diesel or petrol
> * Mitsubishi Colt 1.5 L MIVEC 4 cyl with INVECS-III CVT
>(Asian-Oceanian version only, 72 kW)
> * Mitsubishi Lancer 1.6 L/1.8 L MIVEC 4 cyl with INVECS-III CVT
>(Asian version only)
> * MG F/MG TF 1.8L
> * BMW MINI One and Cooper.
> * Nissan Altima (from 2007)
> * Nissan Cube
> * Nissan Maxima (from 2007)
> * Nissan Micra 1.0 L/1.3 L
> * Nissan Murano 3.5 L
> * Nissan Primera 2.0 L
> * Nissan Sentra (from 2007)
> * Nissan Serena 2.0 L
> * Nissan Skyline 350GT-8
> * Nissan Tiida / Versa
> * Opel Vectra 1.8 L
> * Rover 25
> * Rover 45
> * Rover Streetwise
> * Saturn ION Quad Coupe (2003-2004)
> * Saturn VUE 2.2 L AWD (2002-2005), 2.2 FWD (2002-2004)

I am a little skeptical of those dates. I didn't think they were on
the market that long before it was discovered that every single one of
them breaks. And GM wonders why it is going out of business. LOL


> * Subaru R1
> * Subaru R2
> * Subaru Stella

Subaru Justy (probably equals one of above models) was sold with a CVT
in the US for a few years in the 90's. Subaru hasn't sold a CVT in
the US since.

> * Toyota Highlander Hybrid 3.3 L 6 cyl
> * Toyota Camry Hybrid 2.4L 4 cyl
> * Toyota Prius 1.5 L 4 cyl
>
>
>Dan D
>'04 A4 1.8Tq 6-speed

 

On 8 Jan 2007 06:09:03 -0800, "Dano58" <dan.dibiase@gmail.com> wrote:

>Interesting discussion I started here, I guess....!
>
>I've driven the CVT in an Audi A4 loaner and thought it was weird at
>first (as someone else noted). But it also had 'sport' settings where
>it would 'shift' thru seven 'gears'. There are more CVT's out there
>than you think - off the top of my head, I can think of the Audi (A4
>non-quattro auto models), Ford Freestyle cross-over, and Nissan Altima,
>Murano, Maxima and Versa.* I think some version of the Ford Five
>Hundred has it as well. So, they are becoming more popular.
>
>The best compromise seems to be the automated manual transmissions -
>they are a true manual trans with an automated clutch. No torque
>converter. ( http://en.wikipedia.org/wiki/Direct-Shift_Gearbox )
>Audi's DSG is commonly considered the best example, although BMW has
>one (whch regularly gets panned for poor auto shifting). Porsche may
>have one as well. I've driven the DSG and it is excellent, very fast
>shifting and a decent auto mode as well. But I still prefer a
>conventional manual transmission.
>
>For the Ody, I'm prefectly happy with an automatic.

I would really prefer that Honda would make a Volvo 240 wagon with
performance suspension and an MT, but I have pretty much given up
hope.


>*Oh, Wiki has a list of CVT equipped autos world-wide.

See my comments below. Few of these are currently available in the
US,. If you eliminate the hybrids, I think there are only about
three. Partly this is due to most CVTs being designed for small
engines.

Most CVT designs seem to be reliable and the efficiency improvement is
significant compared to conventional ATs. I really think that the
test drive turns off a lot of buyers because it is so unconventional.
Honda is apparently selling a "7-speed CVT" - talk about an oxymoron.
This is a sure sign that buyers are turned off by normal CVT
operation. Hybrids may be the thing that brings CVTs out of the
closet.

See comments below.

> * Audi A4 2.0/1.8T/2.4/3.0/2.5 TDI
> * Audi A6 2.0/1.8T/2.4/3.0/2.5 TDI
> * Dodge Caliber
> * Fiat Punto 1.2 L
> * Ford Escape Hybrid 2.3 L 4 cyl
> * Ford Five Hundred 3.0 L 6 cyl
> * Ford Focus C-MAX 1.6 L TDCi 110 PS
> * Ford Freestyle 3.0 L 6 cyl
> * Honda Civic HX 1.7 L 4 cyl
> * Honda Civic Hybrid 1.3 L 4 cyl

The only US Civic currently offered with a CVT is the Hybrid.

> * Honda City 1.5 L

I haven't heard of a Honda City in a long, long time. Are they still
sold?

> * Honda HR-V 1.6 L

Never sold in US.

> * Honda Insight 1.0 L 3 cyl

Discontinued - will probably be replaced.


> * Honda Jazz 1.4L / Honda Fit 1.3 L/1.5 L

No CVT in US market.

> * Hyundai Azera 3.8 Lambda
> * Hyundai Sonata 3.3 Lambda
> * Jeep Compass 2.4 L
> * Lexus GS450h 3.5 L 6 cyl
> * Lexus RX400h 3.3 L 6 cyl
> * Mercedes-Benz A-Class
>
> * Mercedes-Benz B-Class
> * Mercury Montego 3.0 L 6 cyl
> * Microcar MC1/MC2 505cc 2 cyl diesel or petrol
> * Microcar Virgo 505cc 2 cyl diesel or petrol
> * Mitsubishi Colt 1.5 L MIVEC 4 cyl with INVECS-III CVT
>(Asian-Oceanian version only, 72 kW)
> * Mitsubishi Lancer 1.6 L/1.8 L MIVEC 4 cyl with INVECS-III CVT
>(Asian version only)
> * MG F/MG TF 1.8L
> * BMW MINI One and Cooper.
> * Nissan Altima (from 2007)
> * Nissan Cube
> * Nissan Maxima (from 2007)
> * Nissan Micra 1.0 L/1.3 L
> * Nissan Murano 3.5 L
> * Nissan Primera 2.0 L
> * Nissan Sentra (from 2007)
> * Nissan Serena 2.0 L
> * Nissan Skyline 350GT-8
> * Nissan Tiida / Versa
> * Opel Vectra 1.8 L
> * Rover 25
> * Rover 45
> * Rover Streetwise
> * Saturn ION Quad Coupe (2003-2004)
> * Saturn VUE 2.2 L AWD (2002-2005), 2.2 FWD (2002-2004)

I am a little skeptical of those dates. I didn't think they were on
the market that long before it was discovered that every single one of
them breaks. And GM wonders why it is going out of business. LOL


> * Subaru R1
> * Subaru R2
> * Subaru Stella

Subaru Justy (probably equals one of above models) was sold with a CVT
in the US for a few years in the 90's. Subaru hasn't sold a CVT in
the US since.

> * Toyota Highlander Hybrid 3.3 L 6 cyl
> * Toyota Camry Hybrid 2.4L 4 cyl
> * Toyota Prius 1.5 L 4 cyl
>
>
>Dan D
>'04 A4 1.8Tq 6-speed

 

On 8 Jan 2007 06:09:03 -0800, "Dano58" <dan.dibiase@gmail.com> wrote:

>Interesting discussion I started here, I guess....!
>
>I've driven the CVT in an Audi A4 loaner and thought it was weird at
>first (as someone else noted). But it also had 'sport' settings where
>it would 'shift' thru seven 'gears'. There are more CVT's out there
>than you think - off the top of my head, I can think of the Audi (A4
>non-quattro auto models), Ford Freestyle cross-over, and Nissan Altima,
>Murano, Maxima and Versa.* I think some version of the Ford Five
>Hundred has it as well. So, they are becoming more popular.
>
>The best compromise seems to be the automated manual transmissions -
>they are a true manual trans with an automated clutch. No torque
>converter. ( http://en.wikipedia.org/wiki/Direct-Shift_Gearbox )
>Audi's DSG is commonly considered the best example, although BMW has
>one (whch regularly gets panned for poor auto shifting). Porsche may
>have one as well. I've driven the DSG and it is excellent, very fast
>shifting and a decent auto mode as well. But I still prefer a
>conventional manual transmission.
>
>For the Ody, I'm prefectly happy with an automatic.

I would really prefer that Honda would make a Volvo 240 wagon with
performance suspension and an MT, but I have pretty much given up
hope.


>*Oh, Wiki has a list of CVT equipped autos world-wide.

See my comments below. Few of these are currently available in the
US,. If you eliminate the hybrids, I think there are only about
three. Partly this is due to most CVTs being designed for small
engines.

Most CVT designs seem to be reliable and the efficiency improvement is
significant compared to conventional ATs. I really think that the
test drive turns off a lot of buyers because it is so unconventional.
Honda is apparently selling a "7-speed CVT" - talk about an oxymoron.
This is a sure sign that buyers are turned off by normal CVT
operation. Hybrids may be the thing that brings CVTs out of the
closet.

See comments below.

> * Audi A4 2.0/1.8T/2.4/3.0/2.5 TDI
> * Audi A6 2.0/1.8T/2.4/3.0/2.5 TDI
> * Dodge Caliber
> * Fiat Punto 1.2 L
> * Ford Escape Hybrid 2.3 L 4 cyl
> * Ford Five Hundred 3.0 L 6 cyl
> * Ford Focus C-MAX 1.6 L TDCi 110 PS
> * Ford Freestyle 3.0 L 6 cyl
> * Honda Civic HX 1.7 L 4 cyl
> * Honda Civic Hybrid 1.3 L 4 cyl

The only US Civic currently offered with a CVT is the Hybrid.

> * Honda City 1.5 L

I haven't heard of a Honda City in a long, long time. Are they still
sold?

> * Honda HR-V 1.6 L

Never sold in US.

> * Honda Insight 1.0 L 3 cyl

Discontinued - will probably be replaced.


> * Honda Jazz 1.4L / Honda Fit 1.3 L/1.5 L

No CVT in US market.

> * Hyundai Azera 3.8 Lambda
> * Hyundai Sonata 3.3 Lambda
> * Jeep Compass 2.4 L
> * Lexus GS450h 3.5 L 6 cyl
> * Lexus RX400h 3.3 L 6 cyl
> * Mercedes-Benz A-Class
>
> * Mercedes-Benz B-Class
> * Mercury Montego 3.0 L 6 cyl
> * Microcar MC1/MC2 505cc 2 cyl diesel or petrol
> * Microcar Virgo 505cc 2 cyl diesel or petrol
> * Mitsubishi Colt 1.5 L MIVEC 4 cyl with INVECS-III CVT
>(Asian-Oceanian version only, 72 kW)
> * Mitsubishi Lancer 1.6 L/1.8 L MIVEC 4 cyl with INVECS-III CVT
>(Asian version only)
> * MG F/MG TF 1.8L
> * BMW MINI One and Cooper.
> * Nissan Altima (from 2007)
> * Nissan Cube
> * Nissan Maxima (from 2007)
> * Nissan Micra 1.0 L/1.3 L
> * Nissan Murano 3.5 L
> * Nissan Primera 2.0 L
> * Nissan Sentra (from 2007)
> * Nissan Serena 2.0 L
> * Nissan Skyline 350GT-8
> * Nissan Tiida / Versa
> * Opel Vectra 1.8 L
> * Rover 25
> * Rover 45
> * Rover Streetwise
> * Saturn ION Quad Coupe (2003-2004)
> * Saturn VUE 2.2 L AWD (2002-2005), 2.2 FWD (2002-2004)

I am a little skeptical of those dates. I didn't think they were on
the market that long before it was discovered that every single one of
them breaks. And GM wonders why it is going out of business. LOL


> * Subaru R1
> * Subaru R2
> * Subaru Stella

Subaru Justy (probably equals one of above models) was sold with a CVT
in the US for a few years in the 90's. Subaru hasn't sold a CVT in
the US since.

> * Toyota Highlander Hybrid 3.3 L 6 cyl
> * Toyota Camry Hybrid 2.4L 4 cyl
> * Toyota Prius 1.5 L 4 cyl
>
>
>Dan D
>'04 A4 1.8Tq 6-speed

 

On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>> toward automatic operation and discourage manual operation.
>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>> /can/ flip up and down at will.
>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>> on braking. not gentle braking, but harder braking.
>>
>> It is not a bad thing, I just don't care for it. If I want to
>> downshift, I can do that. If I don't want to, I don't like the car
>> doing it on its own.
>
>why not? it's just like you'd have on a stick.

Not sure I understand. My GS-R never downshifts on its own.

>>
>>>> When you
>>>> shift into 3 does it effectively double clutch?
>>> pointless exercise on an automatic. but even then, on the modern autos,
>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>> meshed to the gear on shift.
>>
>> That is what I mean. I figured they had fixed that aspect which is
>> the worst part of the older ATs.
>>
>>>>>> Also, I
>>>>>> don't particularly care for the slippage of the torque converter.
>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>> much smoother of course]?
>>>> Well, as you point out, I don't have any experience with modern high
>>>> end luxury cars, but I note that at least more modest cars generally
>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>> they now mostly have five gears, I would assume that means they are
>>>> slipping.
>>> there's no slipping unless the lock-up clutch is released. see below.
>>>
>>>> Actually, the slipping is partly by design, the so-called
>>>> torque multiplier effect.
>>> yes, that's what a torque converter does.
>>>
>>>> Basically, if you are cruising along and
>>>> you give it a little gas, but not enough to force a downshift, you
>>>> will see the rpms jump up immediately.
>>> that's because the lockup clutch is released to allow more torque. more
>>> flexibility than a stick where you'd have to shift.
>>
>> But that is the slippage. The engine speeds up races up ahead of any
>> change in vehicle speed.
>
>but i don't understand the problem - what's wrong with it? engines are
>not perfect across all rev ranges - why not let a computer manage the
>efficiency curves - for that's what's happening.

It is just a personal preference. I like the engine to be positively
coupled to the wheels.

>> It is like a slipping clutch. As for more
>> torque (horsepower really) a lot of that is eaten up by the
>> inefficiency of the torque converter.
>
>how is a slipping clutch more efficient? [it's not.]

No, I understand that (unlike a slipping clutch) there is a benefit to
the slip designed into the AT. I just don't like the feel of it and
the benefit is more than eaten up by the inefficiencies that come with
it.

>> On cars where you can get a MT
>> or AT with the same engine, the MT is almost always faster and gets
>> better mileage.
>
>not so with the modern autos. and that's one of the big things about
>honda autos - it's basically a standard transmission with clutch packs
>instead of synchros. inherently more efficient than planetary gears.

Looking at the differences between the ATs in the econo cars tested by
CR, Honda looks about as good as the other ATs (except for the CVT.)


>>>> The ultimate "torque multiplier" is a CVT.
>>> that's different - it's not a torque multiplier.
>>
>> Neither is the conventional AT, it just has a clever design to let the
>> engine speed up ahead of the vehicle speed without shifting. It is
>> basically like a limited range CVT.
>
>no dude, they're totally different. "torque multiplier" is something a
>torque converter can do - hence its name. everything else is ratio
>control, be it continuously variable or discrete.

OK, explain it to me. My understanding is that it is just a trick to
get the engine running at a slightly higher rpm to produce more power.
Kind of like a mini downshift. All car transmissions are torque
multipliers. They take high rpm/low torque and turn it into low rpm
high torque. If it were perfectly efficient, the power output would
be equal to input but of course it is always less. No way to get more
power out unless you put more power in, i.e. run the engine at higher
rpm.

>>> if is however a great
>>> way of achieving absolute optimum gear for all conditions.
>>
>> I agree that it has a big theoretical advantage, especially compared
>> to a conventional AT.
>
>compared to /any/ transmission. there are mechanical efficiency issues
>with the friction interface, but that is more than outweighed by ratio
>flexibility and ability to keep the engine at its most efficient.

The why doesn't the Versa with a CVT get better mileage or accelerate
faster than the Versa with an MT? Unfortunately, there are few cars
which allow you to directly compare CVT vs. MT.

>>>> A lot of people don't like
>>>> them at all, but others say they get used to it. (The perception
>>>> problem is so bad that some manufacturers program virtual gears into
>>>> them thereby defeating the chief advantage of the CVT.)
>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>> quite fun! this particular model had 2 independent drives too, so not
>>> only did you have optimum gearing, you had limited slip diff benefits in
>>> snow & ice too.
>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>
>> That was the original CVT. Do you remember who offered the first CVT
>> in the US. (I don't think they ever sold the Daffodil here.)
>
>subaru?

That is what I recall. The car was called the Justy.

>>>> I only rode
>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>> that application. He drove it fairly aggressively too - we hit almost
>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>> know if I would like it or not.
>>> if you're not used to traditional automatics, the transition is easy.
>>> if you're used to traditional autos, its weird for a few minutes because
>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>
>> Again though, I am not sure they are any faster or more efficient than
>> a good MT.
>
>well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.

I think the Honda 600 would have blown its petals off. ;-)

>> Consumer Reports tested the Versa with MT and with CVT.
>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>> CR panned that MT.) They also tested MT and (conventional) AT
>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>
>that depends on the management system. the modern cvt's "simulate" gear
>shifts which is the dumbest damned thing since it's not utilizing the
>inherent benefit of the system! on that basis, i'm not surprised.

Does the Versa do that? CR didn't mention it.

>> And yet, there is hardly a proliferation of CVTs on the market. Most
>> of them seem to be on hybrids in fact.
>
>that's consumer and mechanic inertia - nothing to do with benefits or
>reliability. trust me on that one - i've driven the daf for an extended
>period and it's a great system.

Maybe. I would gladly trade the AT in my Ody for one if it was proven
reliable. Not all are. The on in the Saturn Vue was a disaster, but
I guess you have to expect that from GM. The Japanese units don't
seem to have any problems.

 

On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>> toward automatic operation and discourage manual operation.
>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>> /can/ flip up and down at will.
>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>> on braking. not gentle braking, but harder braking.
>>
>> It is not a bad thing, I just don't care for it. If I want to
>> downshift, I can do that. If I don't want to, I don't like the car
>> doing it on its own.
>
>why not? it's just like you'd have on a stick.

Not sure I understand. My GS-R never downshifts on its own.

>>
>>>> When you
>>>> shift into 3 does it effectively double clutch?
>>> pointless exercise on an automatic. but even then, on the modern autos,
>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>> meshed to the gear on shift.
>>
>> That is what I mean. I figured they had fixed that aspect which is
>> the worst part of the older ATs.
>>
>>>>>> Also, I
>>>>>> don't particularly care for the slippage of the torque converter.
>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>> much smoother of course]?
>>>> Well, as you point out, I don't have any experience with modern high
>>>> end luxury cars, but I note that at least more modest cars generally
>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>> they now mostly have five gears, I would assume that means they are
>>>> slipping.
>>> there's no slipping unless the lock-up clutch is released. see below.
>>>
>>>> Actually, the slipping is partly by design, the so-called
>>>> torque multiplier effect.
>>> yes, that's what a torque converter does.
>>>
>>>> Basically, if you are cruising along and
>>>> you give it a little gas, but not enough to force a downshift, you
>>>> will see the rpms jump up immediately.
>>> that's because the lockup clutch is released to allow more torque. more
>>> flexibility than a stick where you'd have to shift.
>>
>> But that is the slippage. The engine speeds up races up ahead of any
>> change in vehicle speed.
>
>but i don't understand the problem - what's wrong with it? engines are
>not perfect across all rev ranges - why not let a computer manage the
>efficiency curves - for that's what's happening.

It is just a personal preference. I like the engine to be positively
coupled to the wheels.

>> It is like a slipping clutch. As for more
>> torque (horsepower really) a lot of that is eaten up by the
>> inefficiency of the torque converter.
>
>how is a slipping clutch more efficient? [it's not.]

No, I understand that (unlike a slipping clutch) there is a benefit to
the slip designed into the AT. I just don't like the feel of it and
the benefit is more than eaten up by the inefficiencies that come with
it.

>> On cars where you can get a MT
>> or AT with the same engine, the MT is almost always faster and gets
>> better mileage.
>
>not so with the modern autos. and that's one of the big things about
>honda autos - it's basically a standard transmission with clutch packs
>instead of synchros. inherently more efficient than planetary gears.

Looking at the differences between the ATs in the econo cars tested by
CR, Honda looks about as good as the other ATs (except for the CVT.)


>>>> The ultimate "torque multiplier" is a CVT.
>>> that's different - it's not a torque multiplier.
>>
>> Neither is the conventional AT, it just has a clever design to let the
>> engine speed up ahead of the vehicle speed without shifting. It is
>> basically like a limited range CVT.
>
>no dude, they're totally different. "torque multiplier" is something a
>torque converter can do - hence its name. everything else is ratio
>control, be it continuously variable or discrete.

OK, explain it to me. My understanding is that it is just a trick to
get the engine running at a slightly higher rpm to produce more power.
Kind of like a mini downshift. All car transmissions are torque
multipliers. They take high rpm/low torque and turn it into low rpm
high torque. If it were perfectly efficient, the power output would
be equal to input but of course it is always less. No way to get more
power out unless you put more power in, i.e. run the engine at higher
rpm.

>>> if is however a great
>>> way of achieving absolute optimum gear for all conditions.
>>
>> I agree that it has a big theoretical advantage, especially compared
>> to a conventional AT.
>
>compared to /any/ transmission. there are mechanical efficiency issues
>with the friction interface, but that is more than outweighed by ratio
>flexibility and ability to keep the engine at its most efficient.

The why doesn't the Versa with a CVT get better mileage or accelerate
faster than the Versa with an MT? Unfortunately, there are few cars
which allow you to directly compare CVT vs. MT.

>>>> A lot of people don't like
>>>> them at all, but others say they get used to it. (The perception
>>>> problem is so bad that some manufacturers program virtual gears into
>>>> them thereby defeating the chief advantage of the CVT.)
>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>> quite fun! this particular model had 2 independent drives too, so not
>>> only did you have optimum gearing, you had limited slip diff benefits in
>>> snow & ice too.
>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>
>> That was the original CVT. Do you remember who offered the first CVT
>> in the US. (I don't think they ever sold the Daffodil here.)
>
>subaru?

That is what I recall. The car was called the Justy.

>>>> I only rode
>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>> that application. He drove it fairly aggressively too - we hit almost
>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>> know if I would like it or not.
>>> if you're not used to traditional automatics, the transition is easy.
>>> if you're used to traditional autos, its weird for a few minutes because
>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>
>> Again though, I am not sure they are any faster or more efficient than
>> a good MT.
>
>well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.

I think the Honda 600 would have blown its petals off. ;-)

>> Consumer Reports tested the Versa with MT and with CVT.
>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>> CR panned that MT.) They also tested MT and (conventional) AT
>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>
>that depends on the management system. the modern cvt's "simulate" gear
>shifts which is the dumbest damned thing since it's not utilizing the
>inherent benefit of the system! on that basis, i'm not surprised.

Does the Versa do that? CR didn't mention it.

>> And yet, there is hardly a proliferation of CVTs on the market. Most
>> of them seem to be on hybrids in fact.
>
>that's consumer and mechanic inertia - nothing to do with benefits or
>reliability. trust me on that one - i've driven the daf for an extended
>period and it's a great system.

Maybe. I would gladly trade the AT in my Ody for one if it was proven
reliable. Not all are. The on in the Saturn Vue was a disaster, but
I guess you have to expect that from GM. The Japanese units don't
seem to have any problems.

 

On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>> toward automatic operation and discourage manual operation.
>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>> /can/ flip up and down at will.
>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>> on braking. not gentle braking, but harder braking.
>>
>> It is not a bad thing, I just don't care for it. If I want to
>> downshift, I can do that. If I don't want to, I don't like the car
>> doing it on its own.
>
>why not? it's just like you'd have on a stick.

Not sure I understand. My GS-R never downshifts on its own.

>>
>>>> When you
>>>> shift into 3 does it effectively double clutch?
>>> pointless exercise on an automatic. but even then, on the modern autos,
>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>> meshed to the gear on shift.
>>
>> That is what I mean. I figured they had fixed that aspect which is
>> the worst part of the older ATs.
>>
>>>>>> Also, I
>>>>>> don't particularly care for the slippage of the torque converter.
>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>> much smoother of course]?
>>>> Well, as you point out, I don't have any experience with modern high
>>>> end luxury cars, but I note that at least more modest cars generally
>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>> they now mostly have five gears, I would assume that means they are
>>>> slipping.
>>> there's no slipping unless the lock-up clutch is released. see below.
>>>
>>>> Actually, the slipping is partly by design, the so-called
>>>> torque multiplier effect.
>>> yes, that's what a torque converter does.
>>>
>>>> Basically, if you are cruising along and
>>>> you give it a little gas, but not enough to force a downshift, you
>>>> will see the rpms jump up immediately.
>>> that's because the lockup clutch is released to allow more torque. more
>>> flexibility than a stick where you'd have to shift.
>>
>> But that is the slippage. The engine speeds up races up ahead of any
>> change in vehicle speed.
>
>but i don't understand the problem - what's wrong with it? engines are
>not perfect across all rev ranges - why not let a computer manage the
>efficiency curves - for that's what's happening.

It is just a personal preference. I like the engine to be positively
coupled to the wheels.

>> It is like a slipping clutch. As for more
>> torque (horsepower really) a lot of that is eaten up by the
>> inefficiency of the torque converter.
>
>how is a slipping clutch more efficient? [it's not.]

No, I understand that (unlike a slipping clutch) there is a benefit to
the slip designed into the AT. I just don't like the feel of it and
the benefit is more than eaten up by the inefficiencies that come with
it.

>> On cars where you can get a MT
>> or AT with the same engine, the MT is almost always faster and gets
>> better mileage.
>
>not so with the modern autos. and that's one of the big things about
>honda autos - it's basically a standard transmission with clutch packs
>instead of synchros. inherently more efficient than planetary gears.

Looking at the differences between the ATs in the econo cars tested by
CR, Honda looks about as good as the other ATs (except for the CVT.)


>>>> The ultimate "torque multiplier" is a CVT.
>>> that's different - it's not a torque multiplier.
>>
>> Neither is the conventional AT, it just has a clever design to let the
>> engine speed up ahead of the vehicle speed without shifting. It is
>> basically like a limited range CVT.
>
>no dude, they're totally different. "torque multiplier" is something a
>torque converter can do - hence its name. everything else is ratio
>control, be it continuously variable or discrete.

OK, explain it to me. My understanding is that it is just a trick to
get the engine running at a slightly higher rpm to produce more power.
Kind of like a mini downshift. All car transmissions are torque
multipliers. They take high rpm/low torque and turn it into low rpm
high torque. If it were perfectly efficient, the power output would
be equal to input but of course it is always less. No way to get more
power out unless you put more power in, i.e. run the engine at higher
rpm.

>>> if is however a great
>>> way of achieving absolute optimum gear for all conditions.
>>
>> I agree that it has a big theoretical advantage, especially compared
>> to a conventional AT.
>
>compared to /any/ transmission. there are mechanical efficiency issues
>with the friction interface, but that is more than outweighed by ratio
>flexibility and ability to keep the engine at its most efficient.

The why doesn't the Versa with a CVT get better mileage or accelerate
faster than the Versa with an MT? Unfortunately, there are few cars
which allow you to directly compare CVT vs. MT.

>>>> A lot of people don't like
>>>> them at all, but others say they get used to it. (The perception
>>>> problem is so bad that some manufacturers program virtual gears into
>>>> them thereby defeating the chief advantage of the CVT.)
>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>> quite fun! this particular model had 2 independent drives too, so not
>>> only did you have optimum gearing, you had limited slip diff benefits in
>>> snow & ice too.
>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>
>> That was the original CVT. Do you remember who offered the first CVT
>> in the US. (I don't think they ever sold the Daffodil here.)
>
>subaru?

That is what I recall. The car was called the Justy.

>>>> I only rode
>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>> that application. He drove it fairly aggressively too - we hit almost
>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>> know if I would like it or not.
>>> if you're not used to traditional automatics, the transition is easy.
>>> if you're used to traditional autos, its weird for a few minutes because
>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>
>> Again though, I am not sure they are any faster or more efficient than
>> a good MT.
>
>well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.

I think the Honda 600 would have blown its petals off. ;-)

>> Consumer Reports tested the Versa with MT and with CVT.
>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>> CR panned that MT.) They also tested MT and (conventional) AT
>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>
>that depends on the management system. the modern cvt's "simulate" gear
>shifts which is the dumbest damned thing since it's not utilizing the
>inherent benefit of the system! on that basis, i'm not surprised.

Does the Versa do that? CR didn't mention it.

>> And yet, there is hardly a proliferation of CVTs on the market. Most
>> of them seem to be on hybrids in fact.
>
>that's consumer and mechanic inertia - nothing to do with benefits or
>reliability. trust me on that one - i've driven the daf for an extended
>period and it's a great system.

Maybe. I would gladly trade the AT in my Ody for one if it was proven
reliable. Not all are. The on in the Saturn Vue was a disaster, but
I guess you have to expect that from GM. The Japanese units don't
seem to have any problems.

 

Gordon McGrew wrote:
> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
> <spamvortex@bad.example.net> wrote:
>
>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>> toward automatic operation and discourage manual operation.
>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>> /can/ flip up and down at will.
>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>> on braking. not gentle braking, but harder braking.
>>> It is not a bad thing, I just don't care for it. If I want to
>>> downshift, I can do that. If I don't want to, I don't like the car
>>> doing it on its own.
>> why not? it's just like you'd have on a stick.
>
> Not sure I understand. My GS-R never downshifts on its own.

if it doesn't, then there's something wrong. how old is it?

>
>>>>> When you
>>>>> shift into 3 does it effectively double clutch?
>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>> meshed to the gear on shift.
>>> That is what I mean. I figured they had fixed that aspect which is
>>> the worst part of the older ATs.
>>>
>>>>>>> Also, I
>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>> much smoother of course]?
>>>>> Well, as you point out, I don't have any experience with modern high
>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>> they now mostly have five gears, I would assume that means they are
>>>>> slipping.
>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>
>>>>> Actually, the slipping is partly by design, the so-called
>>>>> torque multiplier effect.
>>>> yes, that's what a torque converter does.
>>>>
>>>>> Basically, if you are cruising along and
>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>> will see the rpms jump up immediately.
>>>> that's because the lockup clutch is released to allow more torque. more
>>>> flexibility than a stick where you'd have to shift.
>>> But that is the slippage. The engine speeds up races up ahead of any
>>> change in vehicle speed.
>> but i don't understand the problem - what's wrong with it? engines are
>> not perfect across all rev ranges - why not let a computer manage the
>> efficiency curves - for that's what's happening.
>
> It is just a personal preference. I like the engine to be positively
> coupled to the wheels.

that's what the lockup clutch in the torque converter is for.

>
>>> It is like a slipping clutch. As for more
>>> torque (horsepower really) a lot of that is eaten up by the
>>> inefficiency of the torque converter.
>> how is a slipping clutch more efficient? [it's not.]
>
> No, I understand that (unlike a slipping clutch) there is a benefit to
> the slip designed into the AT. I just don't like the feel of it and
> the benefit is more than eaten up by the inefficiencies that come with
> it.

you'd hate cvt. there's no "relationship" between revs and engine speed
at all.

>
>>> On cars where you can get a MT
>>> or AT with the same engine, the MT is almost always faster and gets
>>> better mileage.
>> not so with the modern autos. and that's one of the big things about
>> honda autos - it's basically a standard transmission with clutch packs
>> instead of synchros. inherently more efficient than planetary gears.
>
> Looking at the differences between the ATs in the econo cars tested by
> CR, Honda looks about as good as the other ATs (except for the CVT.)

you're looking at fuel economy, right?

>
>
>>>>> The ultimate "torque multiplier" is a CVT.
>>>> that's different - it's not a torque multiplier.
>>> Neither is the conventional AT, it just has a clever design to let the
>>> engine speed up ahead of the vehicle speed without shifting. It is
>>> basically like a limited range CVT.
>> no dude, they're totally different. "torque multiplier" is something a
>> torque converter can do - hence its name. everything else is ratio
>> control, be it continuously variable or discrete.
>
> OK, explain it to me. My understanding is that it is just a trick to
> get the engine running at a slightly higher rpm to produce more power.
> Kind of like a mini downshift. All car transmissions are torque
> multipliers.

ok, yes, but we're talking about different things. torque converters
can increase torque output from a little to a lot in a very limited rev
range. ratio change is something different and that's what the gears
are for.

> They take high rpm/low torque and turn it into low rpm
> high torque. If it were perfectly efficient, the power output would
> be equal to input but of course it is always less. No way to get more
> power out unless you put more power in, i.e. run the engine at higher
> rpm.

see above.

>
>>>> if is however a great
>>>> way of achieving absolute optimum gear for all conditions.
>>> I agree that it has a big theoretical advantage, especially compared
>>> to a conventional AT.
>> compared to /any/ transmission. there are mechanical efficiency issues
>> with the friction interface, but that is more than outweighed by ratio
>> flexibility and ability to keep the engine at its most efficient.
>
> The why doesn't the Versa with a CVT get better mileage or accelerate
> faster than the Versa with an MT? Unfortunately, there are few cars
> which allow you to directly compare CVT vs. MT.

civic hx was significantly more fuel efficient than the stick.

>
>>>>> A lot of people don't like
>>>>> them at all, but others say they get used to it. (The perception
>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>> them thereby defeating the chief advantage of the CVT.)
>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>> quite fun! this particular model had 2 independent drives too, so not
>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>> snow & ice too.
>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>> That was the original CVT. Do you remember who offered the first CVT
>>> in the US. (I don't think they ever sold the Daffodil here.)
>> subaru?
>
> That is what I recall. The car was called the Justy.
>
>>>>> I only rode
>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>> know if I would like it or not.
>>>> if you're not used to traditional automatics, the transition is easy.
>>>> if you're used to traditional autos, its weird for a few minutes because
>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>> Again though, I am not sure they are any faster or more efficient than
>>> a good MT.
>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>
> I think the Honda 600 would have blown its petals off. ;-)
>
>>> Consumer Reports tested the Versa with MT and with CVT.
>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>> CR panned that MT.) They also tested MT and (conventional) AT
>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>> that depends on the management system. the modern cvt's "simulate" gear
>> shifts which is the dumbest damned thing since it's not utilizing the
>> inherent benefit of the system! on that basis, i'm not surprised.
>
> Does the Versa do that? CR didn't mention it.

don't know. given "consumer demand", i expect so.

>
>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>> of them seem to be on hybrids in fact.
>> that's consumer and mechanic inertia - nothing to do with benefits or
>> reliability. trust me on that one - i've driven the daf for an extended
>> period and it's a great system.
>
> Maybe. I would gladly trade the AT in my Ody for one if it was proven
> reliable. Not all are. The on in the Saturn Vue was a disaster, but
> I guess you have to expect that from GM. The Japanese units don't
> seem to have any problems.

i've never heard of problems with the civic hx.

 

Gordon McGrew wrote:
> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
> <spamvortex@bad.example.net> wrote:
>
>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>> toward automatic operation and discourage manual operation.
>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>> /can/ flip up and down at will.
>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>> on braking. not gentle braking, but harder braking.
>>> It is not a bad thing, I just don't care for it. If I want to
>>> downshift, I can do that. If I don't want to, I don't like the car
>>> doing it on its own.
>> why not? it's just like you'd have on a stick.
>
> Not sure I understand. My GS-R never downshifts on its own.

if it doesn't, then there's something wrong. how old is it?

>
>>>>> When you
>>>>> shift into 3 does it effectively double clutch?
>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>> meshed to the gear on shift.
>>> That is what I mean. I figured they had fixed that aspect which is
>>> the worst part of the older ATs.
>>>
>>>>>>> Also, I
>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>> much smoother of course]?
>>>>> Well, as you point out, I don't have any experience with modern high
>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>> they now mostly have five gears, I would assume that means they are
>>>>> slipping.
>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>
>>>>> Actually, the slipping is partly by design, the so-called
>>>>> torque multiplier effect.
>>>> yes, that's what a torque converter does.
>>>>
>>>>> Basically, if you are cruising along and
>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>> will see the rpms jump up immediately.
>>>> that's because the lockup clutch is released to allow more torque. more
>>>> flexibility than a stick where you'd have to shift.
>>> But that is the slippage. The engine speeds up races up ahead of any
>>> change in vehicle speed.
>> but i don't understand the problem - what's wrong with it? engines are
>> not perfect across all rev ranges - why not let a computer manage the
>> efficiency curves - for that's what's happening.
>
> It is just a personal preference. I like the engine to be positively
> coupled to the wheels.

that's what the lockup clutch in the torque converter is for.

>
>>> It is like a slipping clutch. As for more
>>> torque (horsepower really) a lot of that is eaten up by the
>>> inefficiency of the torque converter.
>> how is a slipping clutch more efficient? [it's not.]
>
> No, I understand that (unlike a slipping clutch) there is a benefit to
> the slip designed into the AT. I just don't like the feel of it and
> the benefit is more than eaten up by the inefficiencies that come with
> it.

you'd hate cvt. there's no "relationship" between revs and engine speed
at all.

>
>>> On cars where you can get a MT
>>> or AT with the same engine, the MT is almost always faster and gets
>>> better mileage.
>> not so with the modern autos. and that's one of the big things about
>> honda autos - it's basically a standard transmission with clutch packs
>> instead of synchros. inherently more efficient than planetary gears.
>
> Looking at the differences between the ATs in the econo cars tested by
> CR, Honda looks about as good as the other ATs (except for the CVT.)

you're looking at fuel economy, right?

>
>
>>>>> The ultimate "torque multiplier" is a CVT.
>>>> that's different - it's not a torque multiplier.
>>> Neither is the conventional AT, it just has a clever design to let the
>>> engine speed up ahead of the vehicle speed without shifting. It is
>>> basically like a limited range CVT.
>> no dude, they're totally different. "torque multiplier" is something a
>> torque converter can do - hence its name. everything else is ratio
>> control, be it continuously variable or discrete.
>
> OK, explain it to me. My understanding is that it is just a trick to
> get the engine running at a slightly higher rpm to produce more power.
> Kind of like a mini downshift. All car transmissions are torque
> multipliers.

ok, yes, but we're talking about different things. torque converters
can increase torque output from a little to a lot in a very limited rev
range. ratio change is something different and that's what the gears
are for.

> They take high rpm/low torque and turn it into low rpm
> high torque. If it were perfectly efficient, the power output would
> be equal to input but of course it is always less. No way to get more
> power out unless you put more power in, i.e. run the engine at higher
> rpm.

see above.

>
>>>> if is however a great
>>>> way of achieving absolute optimum gear for all conditions.
>>> I agree that it has a big theoretical advantage, especially compared
>>> to a conventional AT.
>> compared to /any/ transmission. there are mechanical efficiency issues
>> with the friction interface, but that is more than outweighed by ratio
>> flexibility and ability to keep the engine at its most efficient.
>
> The why doesn't the Versa with a CVT get better mileage or accelerate
> faster than the Versa with an MT? Unfortunately, there are few cars
> which allow you to directly compare CVT vs. MT.

civic hx was significantly more fuel efficient than the stick.

>
>>>>> A lot of people don't like
>>>>> them at all, but others say they get used to it. (The perception
>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>> them thereby defeating the chief advantage of the CVT.)
>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>> quite fun! this particular model had 2 independent drives too, so not
>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>> snow & ice too.
>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>> That was the original CVT. Do you remember who offered the first CVT
>>> in the US. (I don't think they ever sold the Daffodil here.)
>> subaru?
>
> That is what I recall. The car was called the Justy.
>
>>>>> I only rode
>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>> know if I would like it or not.
>>>> if you're not used to traditional automatics, the transition is easy.
>>>> if you're used to traditional autos, its weird for a few minutes because
>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>> Again though, I am not sure they are any faster or more efficient than
>>> a good MT.
>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>
> I think the Honda 600 would have blown its petals off. ;-)
>
>>> Consumer Reports tested the Versa with MT and with CVT.
>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>> CR panned that MT.) They also tested MT and (conventional) AT
>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>> that depends on the management system. the modern cvt's "simulate" gear
>> shifts which is the dumbest damned thing since it's not utilizing the
>> inherent benefit of the system! on that basis, i'm not surprised.
>
> Does the Versa do that? CR didn't mention it.

don't know. given "consumer demand", i expect so.

>
>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>> of them seem to be on hybrids in fact.
>> that's consumer and mechanic inertia - nothing to do with benefits or
>> reliability. trust me on that one - i've driven the daf for an extended
>> period and it's a great system.
>
> Maybe. I would gladly trade the AT in my Ody for one if it was proven
> reliable. Not all are. The on in the Saturn Vue was a disaster, but
> I guess you have to expect that from GM. The Japanese units don't
> seem to have any problems.

i've never heard of problems with the civic hx.

 

Gordon McGrew wrote:
> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
> <spamvortex@bad.example.net> wrote:
>
>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>> toward automatic operation and discourage manual operation.
>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>> /can/ flip up and down at will.
>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>> on braking. not gentle braking, but harder braking.
>>> It is not a bad thing, I just don't care for it. If I want to
>>> downshift, I can do that. If I don't want to, I don't like the car
>>> doing it on its own.
>> why not? it's just like you'd have on a stick.
>
> Not sure I understand. My GS-R never downshifts on its own.

if it doesn't, then there's something wrong. how old is it?

>
>>>>> When you
>>>>> shift into 3 does it effectively double clutch?
>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>> meshed to the gear on shift.
>>> That is what I mean. I figured they had fixed that aspect which is
>>> the worst part of the older ATs.
>>>
>>>>>>> Also, I
>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>> much smoother of course]?
>>>>> Well, as you point out, I don't have any experience with modern high
>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>> they now mostly have five gears, I would assume that means they are
>>>>> slipping.
>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>
>>>>> Actually, the slipping is partly by design, the so-called
>>>>> torque multiplier effect.
>>>> yes, that's what a torque converter does.
>>>>
>>>>> Basically, if you are cruising along and
>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>> will see the rpms jump up immediately.
>>>> that's because the lockup clutch is released to allow more torque. more
>>>> flexibility than a stick where you'd have to shift.
>>> But that is the slippage. The engine speeds up races up ahead of any
>>> change in vehicle speed.
>> but i don't understand the problem - what's wrong with it? engines are
>> not perfect across all rev ranges - why not let a computer manage the
>> efficiency curves - for that's what's happening.
>
> It is just a personal preference. I like the engine to be positively
> coupled to the wheels.

that's what the lockup clutch in the torque converter is for.

>
>>> It is like a slipping clutch. As for more
>>> torque (horsepower really) a lot of that is eaten up by the
>>> inefficiency of the torque converter.
>> how is a slipping clutch more efficient? [it's not.]
>
> No, I understand that (unlike a slipping clutch) there is a benefit to
> the slip designed into the AT. I just don't like the feel of it and
> the benefit is more than eaten up by the inefficiencies that come with
> it.

you'd hate cvt. there's no "relationship" between revs and engine speed
at all.

>
>>> On cars where you can get a MT
>>> or AT with the same engine, the MT is almost always faster and gets
>>> better mileage.
>> not so with the modern autos. and that's one of the big things about
>> honda autos - it's basically a standard transmission with clutch packs
>> instead of synchros. inherently more efficient than planetary gears.
>
> Looking at the differences between the ATs in the econo cars tested by
> CR, Honda looks about as good as the other ATs (except for the CVT.)

you're looking at fuel economy, right?

>
>
>>>>> The ultimate "torque multiplier" is a CVT.
>>>> that's different - it's not a torque multiplier.
>>> Neither is the conventional AT, it just has a clever design to let the
>>> engine speed up ahead of the vehicle speed without shifting. It is
>>> basically like a limited range CVT.
>> no dude, they're totally different. "torque multiplier" is something a
>> torque converter can do - hence its name. everything else is ratio
>> control, be it continuously variable or discrete.
>
> OK, explain it to me. My understanding is that it is just a trick to
> get the engine running at a slightly higher rpm to produce more power.
> Kind of like a mini downshift. All car transmissions are torque
> multipliers.

ok, yes, but we're talking about different things. torque converters
can increase torque output from a little to a lot in a very limited rev
range. ratio change is something different and that's what the gears
are for.

> They take high rpm/low torque and turn it into low rpm
> high torque. If it were perfectly efficient, the power output would
> be equal to input but of course it is always less. No way to get more
> power out unless you put more power in, i.e. run the engine at higher
> rpm.

see above.

>
>>>> if is however a great
>>>> way of achieving absolute optimum gear for all conditions.
>>> I agree that it has a big theoretical advantage, especially compared
>>> to a conventional AT.
>> compared to /any/ transmission. there are mechanical efficiency issues
>> with the friction interface, but that is more than outweighed by ratio
>> flexibility and ability to keep the engine at its most efficient.
>
> The why doesn't the Versa with a CVT get better mileage or accelerate
> faster than the Versa with an MT? Unfortunately, there are few cars
> which allow you to directly compare CVT vs. MT.

civic hx was significantly more fuel efficient than the stick.

>
>>>>> A lot of people don't like
>>>>> them at all, but others say they get used to it. (The perception
>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>> them thereby defeating the chief advantage of the CVT.)
>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>> quite fun! this particular model had 2 independent drives too, so not
>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>> snow & ice too.
>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>> That was the original CVT. Do you remember who offered the first CVT
>>> in the US. (I don't think they ever sold the Daffodil here.)
>> subaru?
>
> That is what I recall. The car was called the Justy.
>
>>>>> I only rode
>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>> know if I would like it or not.
>>>> if you're not used to traditional automatics, the transition is easy.
>>>> if you're used to traditional autos, its weird for a few minutes because
>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>> Again though, I am not sure they are any faster or more efficient than
>>> a good MT.
>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>
> I think the Honda 600 would have blown its petals off. ;-)
>
>>> Consumer Reports tested the Versa with MT and with CVT.
>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>> CR panned that MT.) They also tested MT and (conventional) AT
>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>> that depends on the management system. the modern cvt's "simulate" gear
>> shifts which is the dumbest damned thing since it's not utilizing the
>> inherent benefit of the system! on that basis, i'm not surprised.
>
> Does the Versa do that? CR didn't mention it.

don't know. given "consumer demand", i expect so.

>
>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>> of them seem to be on hybrids in fact.
>> that's consumer and mechanic inertia - nothing to do with benefits or
>> reliability. trust me on that one - i've driven the daf for an extended
>> period and it's a great system.
>
> Maybe. I would gladly trade the AT in my Ody for one if it was proven
> reliable. Not all are. The on in the Saturn Vue was a disaster, but
> I guess you have to expect that from GM. The Japanese units don't
> seem to have any problems.

i've never heard of problems with the civic hx.

 

On Mon, 08 Jan 2007 21:25:13 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>Gordon McGrew wrote:
>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>> <spamvortex@bad.example.net> wrote:
>>
>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>> /can/ flip up and down at will.
>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>> on braking. not gentle braking, but harder braking.
>>>> It is not a bad thing, I just don't care for it. If I want to
>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>> doing it on its own.
>>> why not? it's just like you'd have on a stick.
>>
>> Not sure I understand. My GS-R never downshifts on its own.
>
>if it doesn't, then there's something wrong. how old is it?

It is a '94 with a 5-speed manual transmission. What kind of MT cars
have you driven that shift themselves???


>
>>
>>>>>> When you
>>>>>> shift into 3 does it effectively double clutch?
>>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>>> meshed to the gear on shift.
>>>> That is what I mean. I figured they had fixed that aspect which is
>>>> the worst part of the older ATs.
>>>>
>>>>>>>> Also, I
>>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>>> much smoother of course]?
>>>>>> Well, as you point out, I don't have any experience with modern high
>>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>>> they now mostly have five gears, I would assume that means they are
>>>>>> slipping.
>>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>>
>>>>>> Actually, the slipping is partly by design, the so-called
>>>>>> torque multiplier effect.
>>>>> yes, that's what a torque converter does.
>>>>>
>>>>>> Basically, if you are cruising along and
>>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>>> will see the rpms jump up immediately.
>>>>> that's because the lockup clutch is released to allow more torque. more
>>>>> flexibility than a stick where you'd have to shift.
>>>> But that is the slippage. The engine speeds up races up ahead of any
>>>> change in vehicle speed.
>>> but i don't understand the problem - what's wrong with it? engines are
>>> not perfect across all rev ranges - why not let a computer manage the
>>> efficiency curves - for that's what's happening.
>>
>> It is just a personal preference. I like the engine to be positively
>> coupled to the wheels.
>
>that's what the lockup clutch in the torque converter is for.

But it isn't engaged all the time. When it disengages, that is when
it "slips" and I do not find that satisfying as a driver. Like I said
a the outside, it is a preference for MT. I like to drive cars and
the MT is more enjoyable than the ATs I have driven. I don't like it
shifting when I don't want it to and I don't like the slippy feel of
the torque converter. The fact that the MT is usually faster and more
fuel efficient is a bonus.


>
>>
>>>> It is like a slipping clutch. As for more
>>>> torque (horsepower really) a lot of that is eaten up by the
>>>> inefficiency of the torque converter.
>>> how is a slipping clutch more efficient? [it's not.]
>>
>> No, I understand that (unlike a slipping clutch) there is a benefit to
>> the slip designed into the AT. I just don't like the feel of it and
>> the benefit is more than eaten up by the inefficiencies that come with
>> it.
>
>you'd hate cvt. there's no "relationship" between revs and engine speed
>at all.

I think you are probably right. That is why I mentioned the fact that
the CVT isn't very popular in the US (if anywhere) and I think it is
because lots of people hate it. Why else would Honda sell a 7-speed
CVT?

OTOH, it probably appeals to - or at least doesn't repulse - the
hybrid buyer because it befits the unconventional nature of the car. I
realize there are technical benefits to the combination of hybrid and
CVT, but I am saying that the unconventional nature of the CVT is less
of a negative when you are already committed to buying an
unconventional vehicle. If you are attracted to the hybrid because it
is unconventional, the CVT is a plus.

>>>> On cars where you can get a MT
>>>> or AT with the same engine, the MT is almost always faster and gets
>>>> better mileage.
>>> not so with the modern autos. and that's one of the big things about
>>> honda autos - it's basically a standard transmission with clutch packs
>>> instead of synchros. inherently more efficient than planetary gears.
>>
>> Looking at the differences between the ATs in the econo cars tested by
>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>
>you're looking at fuel economy, right?

Fuel economy was significantly better for the MTs but the biggest
difference was acceleration. The MTs blew the doors off the ATs. In
terms of 0 - 60 time differences, the Yaris AT was the best - "only"
2.1 seconds slower than the MT version. Even the slowest MT car, the
Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
was 1.4 seconds slower than the Versa CVT.

>>
>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>> that's different - it's not a torque multiplier.
>>>> Neither is the conventional AT, it just has a clever design to let the
>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>> basically like a limited range CVT.
>>> no dude, they're totally different. "torque multiplier" is something a
>>> torque converter can do - hence its name. everything else is ratio
>>> control, be it continuously variable or discrete.
>>
>> OK, explain it to me. My understanding is that it is just a trick to
>> get the engine running at a slightly higher rpm to produce more power.
>> Kind of like a mini downshift. All car transmissions are torque
>> multipliers.
>
>ok, yes, but we're talking about different things. torque converters
>can increase torque output from a little to a lot in a very limited rev
>range. ratio change is something different and that's what the gears
>are for.

You understand that the ATs torque output at a certain rpm (i.e. power
transmitted) is higher when the torque multiplication is active. There
are only two way this can happen. The first is to increase the
efficiency of the transmission. I think we can dismiss that. The
other way is to increase the power input. The only way to do that is
to increase the throttle opening or increase the rpm. The throttle
opening is determined by your foot (and it wouldn't be much of a trick
for the torque multiplier to be just an extra jerk on the throttle and
it wouldn't do much good if the throttle were already wide open.)
However, rpm is largely controlled by the transmission. The
transmission allows the engine to run a little faster and therefore
produce more power which is transmitted to the wheels. This is what I
meant by a mini downshift.

>> They take high rpm/low torque and turn it into low rpm
>> high torque. If it were perfectly efficient, the power output would
>> be equal to input but of course it is always less. No way to get more
>> power out unless you put more power in, i.e. run the engine at higher
>> rpm.
>
>see above.
>
>>
>>>>> if is however a great
>>>>> way of achieving absolute optimum gear for all conditions.
>>>> I agree that it has a big theoretical advantage, especially compared
>>>> to a conventional AT.
>>> compared to /any/ transmission. there are mechanical efficiency issues
>>> with the friction interface, but that is more than outweighed by ratio
>>> flexibility and ability to keep the engine at its most efficient.
>>
>> The why doesn't the Versa with a CVT get better mileage or accelerate
>> faster than the Versa with an MT? Unfortunately, there are few cars
>> which allow you to directly compare CVT vs. MT.
>
>civic hx was significantly more fuel efficient than the stick.

I gather that was the CVT-equipped model. They don't sell it anymore.
I guess people hated it more than high fuel costs.

>>
>>>>>> A lot of people don't like
>>>>>> them at all, but others say they get used to it. (The perception
>>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>>> them thereby defeating the chief advantage of the CVT.)
>>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>>> quite fun! this particular model had 2 independent drives too, so not
>>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>>> snow & ice too.
>>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>>> That was the original CVT. Do you remember who offered the first CVT
>>>> in the US. (I don't think they ever sold the Daffodil here.)
>>> subaru?
>>
>> That is what I recall. The car was called the Justy.
>>
>>>>>> I only rode
>>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>>> know if I would like it or not.
>>>>> if you're not used to traditional automatics, the transition is easy.
>>>>> if you're used to traditional autos, its weird for a few minutes because
>>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>>> Again though, I am not sure they are any faster or more efficient than
>>>> a good MT.
>>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>>
>> I think the Honda 600 would have blown its petals off. ;-)
>>
>>>> Consumer Reports tested the Versa with MT and with CVT.
>>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>>> CR panned that MT.) They also tested MT and (conventional) AT
>>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>>> that depends on the management system. the modern cvt's "simulate" gear
>>> shifts which is the dumbest damned thing since it's not utilizing the
>>> inherent benefit of the system! on that basis, i'm not surprised.
>>
>> Does the Versa do that? CR didn't mention it.
>
>don't know. given "consumer demand", i expect so.

Like I said, they hate it just like you think I would. (Actually I
would love to try one, I do think it is a neat idea and it would be
fun for a while at least. Only after the novelty wore off could I
tell you if I like it or hate it. I actually suspect that I would
like it more than a conventional AT.)

Here is an interesting review I found. (It indicates that the Versa
CVT does not have "gears," so the fact that it was slower and less
fuel efficient than the "clunky" MT is significant.) I made one
editorial comment in brackets.

--quote--
But the CVT is the one that shines. Its proprietary design, benefiting
from Nissan's global cooperation with French carmaker Renault, is
uncanny in the way it maintains optimal engine rpm within the most
fuel-efficient torque range. It senses, for example, when the Versa is
proceeding downhill and glides effortlessly into a lower gear range to
slow the car with engine braking. [What if you don't want engine
braking? It is wasting kinetic energy = fuel. What it needs in a
powerful computer with optical sensors to look ahead, evaluate the
situation and decide whether engine braking is advantageous.]
Conversely, under pedal-to-the-floor acceleration, the CVT instantly
launches the engine to its max-torque rpm, then keeps it there
unchanged until a desired highway speed is reached.

This goes against every traditional sensation of driving, wherein gear
changes trigger a momentary drop in rpm as the higher gear ratio is
engaged. There's a lot of mechanical inefficiency in that traditional
gear-change syncopation; and Versa's CVT eliminates it. When first
experiencing the CVT's behavior, it feels wrong, sounds noisy. In
truth, however, it's mostly the lack of noticeable gear changes that's
merely thwarting a driver's subconscious expectation of rising-falling
rpms as gears change.
--end quote--

http://www.carlist.com/newcars/2007/ncr1116.html


>>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>>> of them seem to be on hybrids in fact.
>>> that's consumer and mechanic inertia - nothing to do with benefits or
>>> reliability. trust me on that one - i've driven the daf for an extended
>>> period and it's a great system.
>>
>> Maybe. I would gladly trade the AT in my Ody for one if it was proven
>> reliable. Not all are. The on in the Saturn Vue was a disaster, but
>> I guess you have to expect that from GM. The Japanese units don't
>> seem to have any problems.
>
>i've never heard of problems with the civic hx.

Neither have I, but then there aren't a lot out there.

 

On Mon, 08 Jan 2007 21:25:13 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>Gordon McGrew wrote:
>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>> <spamvortex@bad.example.net> wrote:
>>
>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>> /can/ flip up and down at will.
>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>> on braking. not gentle braking, but harder braking.
>>>> It is not a bad thing, I just don't care for it. If I want to
>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>> doing it on its own.
>>> why not? it's just like you'd have on a stick.
>>
>> Not sure I understand. My GS-R never downshifts on its own.
>
>if it doesn't, then there's something wrong. how old is it?

It is a '94 with a 5-speed manual transmission. What kind of MT cars
have you driven that shift themselves???


>
>>
>>>>>> When you
>>>>>> shift into 3 does it effectively double clutch?
>>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>>> meshed to the gear on shift.
>>>> That is what I mean. I figured they had fixed that aspect which is
>>>> the worst part of the older ATs.
>>>>
>>>>>>>> Also, I
>>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>>> much smoother of course]?
>>>>>> Well, as you point out, I don't have any experience with modern high
>>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>>> they now mostly have five gears, I would assume that means they are
>>>>>> slipping.
>>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>>
>>>>>> Actually, the slipping is partly by design, the so-called
>>>>>> torque multiplier effect.
>>>>> yes, that's what a torque converter does.
>>>>>
>>>>>> Basically, if you are cruising along and
>>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>>> will see the rpms jump up immediately.
>>>>> that's because the lockup clutch is released to allow more torque. more
>>>>> flexibility than a stick where you'd have to shift.
>>>> But that is the slippage. The engine speeds up races up ahead of any
>>>> change in vehicle speed.
>>> but i don't understand the problem - what's wrong with it? engines are
>>> not perfect across all rev ranges - why not let a computer manage the
>>> efficiency curves - for that's what's happening.
>>
>> It is just a personal preference. I like the engine to be positively
>> coupled to the wheels.
>
>that's what the lockup clutch in the torque converter is for.

But it isn't engaged all the time. When it disengages, that is when
it "slips" and I do not find that satisfying as a driver. Like I said
a the outside, it is a preference for MT. I like to drive cars and
the MT is more enjoyable than the ATs I have driven. I don't like it
shifting when I don't want it to and I don't like the slippy feel of
the torque converter. The fact that the MT is usually faster and more
fuel efficient is a bonus.


>
>>
>>>> It is like a slipping clutch. As for more
>>>> torque (horsepower really) a lot of that is eaten up by the
>>>> inefficiency of the torque converter.
>>> how is a slipping clutch more efficient? [it's not.]
>>
>> No, I understand that (unlike a slipping clutch) there is a benefit to
>> the slip designed into the AT. I just don't like the feel of it and
>> the benefit is more than eaten up by the inefficiencies that come with
>> it.
>
>you'd hate cvt. there's no "relationship" between revs and engine speed
>at all.

I think you are probably right. That is why I mentioned the fact that
the CVT isn't very popular in the US (if anywhere) and I think it is
because lots of people hate it. Why else would Honda sell a 7-speed
CVT?

OTOH, it probably appeals to - or at least doesn't repulse - the
hybrid buyer because it befits the unconventional nature of the car. I
realize there are technical benefits to the combination of hybrid and
CVT, but I am saying that the unconventional nature of the CVT is less
of a negative when you are already committed to buying an
unconventional vehicle. If you are attracted to the hybrid because it
is unconventional, the CVT is a plus.

>>>> On cars where you can get a MT
>>>> or AT with the same engine, the MT is almost always faster and gets
>>>> better mileage.
>>> not so with the modern autos. and that's one of the big things about
>>> honda autos - it's basically a standard transmission with clutch packs
>>> instead of synchros. inherently more efficient than planetary gears.
>>
>> Looking at the differences between the ATs in the econo cars tested by
>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>
>you're looking at fuel economy, right?

Fuel economy was significantly better for the MTs but the biggest
difference was acceleration. The MTs blew the doors off the ATs. In
terms of 0 - 60 time differences, the Yaris AT was the best - "only"
2.1 seconds slower than the MT version. Even the slowest MT car, the
Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
was 1.4 seconds slower than the Versa CVT.

>>
>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>> that's different - it's not a torque multiplier.
>>>> Neither is the conventional AT, it just has a clever design to let the
>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>> basically like a limited range CVT.
>>> no dude, they're totally different. "torque multiplier" is something a
>>> torque converter can do - hence its name. everything else is ratio
>>> control, be it continuously variable or discrete.
>>
>> OK, explain it to me. My understanding is that it is just a trick to
>> get the engine running at a slightly higher rpm to produce more power.
>> Kind of like a mini downshift. All car transmissions are torque
>> multipliers.
>
>ok, yes, but we're talking about different things. torque converters
>can increase torque output from a little to a lot in a very limited rev
>range. ratio change is something different and that's what the gears
>are for.

You understand that the ATs torque output at a certain rpm (i.e. power
transmitted) is higher when the torque multiplication is active. There
are only two way this can happen. The first is to increase the
efficiency of the transmission. I think we can dismiss that. The
other way is to increase the power input. The only way to do that is
to increase the throttle opening or increase the rpm. The throttle
opening is determined by your foot (and it wouldn't be much of a trick
for the torque multiplier to be just an extra jerk on the throttle and
it wouldn't do much good if the throttle were already wide open.)
However, rpm is largely controlled by the transmission. The
transmission allows the engine to run a little faster and therefore
produce more power which is transmitted to the wheels. This is what I
meant by a mini downshift.

>> They take high rpm/low torque and turn it into low rpm
>> high torque. If it were perfectly efficient, the power output would
>> be equal to input but of course it is always less. No way to get more
>> power out unless you put more power in, i.e. run the engine at higher
>> rpm.
>
>see above.
>
>>
>>>>> if is however a great
>>>>> way of achieving absolute optimum gear for all conditions.
>>>> I agree that it has a big theoretical advantage, especially compared
>>>> to a conventional AT.
>>> compared to /any/ transmission. there are mechanical efficiency issues
>>> with the friction interface, but that is more than outweighed by ratio
>>> flexibility and ability to keep the engine at its most efficient.
>>
>> The why doesn't the Versa with a CVT get better mileage or accelerate
>> faster than the Versa with an MT? Unfortunately, there are few cars
>> which allow you to directly compare CVT vs. MT.
>
>civic hx was significantly more fuel efficient than the stick.

I gather that was the CVT-equipped model. They don't sell it anymore.
I guess people hated it more than high fuel costs.

>>
>>>>>> A lot of people don't like
>>>>>> them at all, but others say they get used to it. (The perception
>>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>>> them thereby defeating the chief advantage of the CVT.)
>>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>>> quite fun! this particular model had 2 independent drives too, so not
>>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>>> snow & ice too.
>>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>>> That was the original CVT. Do you remember who offered the first CVT
>>>> in the US. (I don't think they ever sold the Daffodil here.)
>>> subaru?
>>
>> That is what I recall. The car was called the Justy.
>>
>>>>>> I only rode
>>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>>> know if I would like it or not.
>>>>> if you're not used to traditional automatics, the transition is easy.
>>>>> if you're used to traditional autos, its weird for a few minutes because
>>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>>> Again though, I am not sure they are any faster or more efficient than
>>>> a good MT.
>>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>>
>> I think the Honda 600 would have blown its petals off. ;-)
>>
>>>> Consumer Reports tested the Versa with MT and with CVT.
>>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>>> CR panned that MT.) They also tested MT and (conventional) AT
>>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>>> that depends on the management system. the modern cvt's "simulate" gear
>>> shifts which is the dumbest damned thing since it's not utilizing the
>>> inherent benefit of the system! on that basis, i'm not surprised.
>>
>> Does the Versa do that? CR didn't mention it.
>
>don't know. given "consumer demand", i expect so.

Like I said, they hate it just like you think I would. (Actually I
would love to try one, I do think it is a neat idea and it would be
fun for a while at least. Only after the novelty wore off could I
tell you if I like it or hate it. I actually suspect that I would
like it more than a conventional AT.)

Here is an interesting review I found. (It indicates that the Versa
CVT does not have "gears," so the fact that it was slower and less
fuel efficient than the "clunky" MT is significant.) I made one
editorial comment in brackets.

--quote--
But the CVT is the one that shines. Its proprietary design, benefiting
from Nissan's global cooperation with French carmaker Renault, is
uncanny in the way it maintains optimal engine rpm within the most
fuel-efficient torque range. It senses, for example, when the Versa is
proceeding downhill and glides effortlessly into a lower gear range to
slow the car with engine braking. [What if you don't want engine
braking? It is wasting kinetic energy = fuel. What it needs in a
powerful computer with optical sensors to look ahead, evaluate the
situation and decide whether engine braking is advantageous.]
Conversely, under pedal-to-the-floor acceleration, the CVT instantly
launches the engine to its max-torque rpm, then keeps it there
unchanged until a desired highway speed is reached.

This goes against every traditional sensation of driving, wherein gear
changes trigger a momentary drop in rpm as the higher gear ratio is
engaged. There's a lot of mechanical inefficiency in that traditional
gear-change syncopation; and Versa's CVT eliminates it. When first
experiencing the CVT's behavior, it feels wrong, sounds noisy. In
truth, however, it's mostly the lack of noticeable gear changes that's
merely thwarting a driver's subconscious expectation of rising-falling
rpms as gears change.
--end quote--

http://www.carlist.com/newcars/2007/ncr1116.html


>>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>>> of them seem to be on hybrids in fact.
>>> that's consumer and mechanic inertia - nothing to do with benefits or
>>> reliability. trust me on that one - i've driven the daf for an extended
>>> period and it's a great system.
>>
>> Maybe. I would gladly trade the AT in my Ody for one if it was proven
>> reliable. Not all are. The on in the Saturn Vue was a disaster, but
>> I guess you have to expect that from GM. The Japanese units don't
>> seem to have any problems.
>
>i've never heard of problems with the civic hx.

Neither have I, but then there aren't a lot out there.

 

On Mon, 08 Jan 2007 21:25:13 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>Gordon McGrew wrote:
>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>> <spamvortex@bad.example.net> wrote:
>>
>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>> /can/ flip up and down at will.
>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>> on braking. not gentle braking, but harder braking.
>>>> It is not a bad thing, I just don't care for it. If I want to
>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>> doing it on its own.
>>> why not? it's just like you'd have on a stick.
>>
>> Not sure I understand. My GS-R never downshifts on its own.
>
>if it doesn't, then there's something wrong. how old is it?

It is a '94 with a 5-speed manual transmission. What kind of MT cars
have you driven that shift themselves???


>
>>
>>>>>> When you
>>>>>> shift into 3 does it effectively double clutch?
>>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>>> meshed to the gear on shift.
>>>> That is what I mean. I figured they had fixed that aspect which is
>>>> the worst part of the older ATs.
>>>>
>>>>>>>> Also, I
>>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>>> much smoother of course]?
>>>>>> Well, as you point out, I don't have any experience with modern high
>>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>>> they now mostly have five gears, I would assume that means they are
>>>>>> slipping.
>>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>>
>>>>>> Actually, the slipping is partly by design, the so-called
>>>>>> torque multiplier effect.
>>>>> yes, that's what a torque converter does.
>>>>>
>>>>>> Basically, if you are cruising along and
>>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>>> will see the rpms jump up immediately.
>>>>> that's because the lockup clutch is released to allow more torque. more
>>>>> flexibility than a stick where you'd have to shift.
>>>> But that is the slippage. The engine speeds up races up ahead of any
>>>> change in vehicle speed.
>>> but i don't understand the problem - what's wrong with it? engines are
>>> not perfect across all rev ranges - why not let a computer manage the
>>> efficiency curves - for that's what's happening.
>>
>> It is just a personal preference. I like the engine to be positively
>> coupled to the wheels.
>
>that's what the lockup clutch in the torque converter is for.

But it isn't engaged all the time. When it disengages, that is when
it "slips" and I do not find that satisfying as a driver. Like I said
a the outside, it is a preference for MT. I like to drive cars and
the MT is more enjoyable than the ATs I have driven. I don't like it
shifting when I don't want it to and I don't like the slippy feel of
the torque converter. The fact that the MT is usually faster and more
fuel efficient is a bonus.


>
>>
>>>> It is like a slipping clutch. As for more
>>>> torque (horsepower really) a lot of that is eaten up by the
>>>> inefficiency of the torque converter.
>>> how is a slipping clutch more efficient? [it's not.]
>>
>> No, I understand that (unlike a slipping clutch) there is a benefit to
>> the slip designed into the AT. I just don't like the feel of it and
>> the benefit is more than eaten up by the inefficiencies that come with
>> it.
>
>you'd hate cvt. there's no "relationship" between revs and engine speed
>at all.

I think you are probably right. That is why I mentioned the fact that
the CVT isn't very popular in the US (if anywhere) and I think it is
because lots of people hate it. Why else would Honda sell a 7-speed
CVT?

OTOH, it probably appeals to - or at least doesn't repulse - the
hybrid buyer because it befits the unconventional nature of the car. I
realize there are technical benefits to the combination of hybrid and
CVT, but I am saying that the unconventional nature of the CVT is less
of a negative when you are already committed to buying an
unconventional vehicle. If you are attracted to the hybrid because it
is unconventional, the CVT is a plus.

>>>> On cars where you can get a MT
>>>> or AT with the same engine, the MT is almost always faster and gets
>>>> better mileage.
>>> not so with the modern autos. and that's one of the big things about
>>> honda autos - it's basically a standard transmission with clutch packs
>>> instead of synchros. inherently more efficient than planetary gears.
>>
>> Looking at the differences between the ATs in the econo cars tested by
>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>
>you're looking at fuel economy, right?

Fuel economy was significantly better for the MTs but the biggest
difference was acceleration. The MTs blew the doors off the ATs. In
terms of 0 - 60 time differences, the Yaris AT was the best - "only"
2.1 seconds slower than the MT version. Even the slowest MT car, the
Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
was 1.4 seconds slower than the Versa CVT.

>>
>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>> that's different - it's not a torque multiplier.
>>>> Neither is the conventional AT, it just has a clever design to let the
>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>> basically like a limited range CVT.
>>> no dude, they're totally different. "torque multiplier" is something a
>>> torque converter can do - hence its name. everything else is ratio
>>> control, be it continuously variable or discrete.
>>
>> OK, explain it to me. My understanding is that it is just a trick to
>> get the engine running at a slightly higher rpm to produce more power.
>> Kind of like a mini downshift. All car transmissions are torque
>> multipliers.
>
>ok, yes, but we're talking about different things. torque converters
>can increase torque output from a little to a lot in a very limited rev
>range. ratio change is something different and that's what the gears
>are for.

You understand that the ATs torque output at a certain rpm (i.e. power
transmitted) is higher when the torque multiplication is active. There
are only two way this can happen. The first is to increase the
efficiency of the transmission. I think we can dismiss that. The
other way is to increase the power input. The only way to do that is
to increase the throttle opening or increase the rpm. The throttle
opening is determined by your foot (and it wouldn't be much of a trick
for the torque multiplier to be just an extra jerk on the throttle and
it wouldn't do much good if the throttle were already wide open.)
However, rpm is largely controlled by the transmission. The
transmission allows the engine to run a little faster and therefore
produce more power which is transmitted to the wheels. This is what I
meant by a mini downshift.

>> They take high rpm/low torque and turn it into low rpm
>> high torque. If it were perfectly efficient, the power output would
>> be equal to input but of course it is always less. No way to get more
>> power out unless you put more power in, i.e. run the engine at higher
>> rpm.
>
>see above.
>
>>
>>>>> if is however a great
>>>>> way of achieving absolute optimum gear for all conditions.
>>>> I agree that it has a big theoretical advantage, especially compared
>>>> to a conventional AT.
>>> compared to /any/ transmission. there are mechanical efficiency issues
>>> with the friction interface, but that is more than outweighed by ratio
>>> flexibility and ability to keep the engine at its most efficient.
>>
>> The why doesn't the Versa with a CVT get better mileage or accelerate
>> faster than the Versa with an MT? Unfortunately, there are few cars
>> which allow you to directly compare CVT vs. MT.
>
>civic hx was significantly more fuel efficient than the stick.

I gather that was the CVT-equipped model. They don't sell it anymore.
I guess people hated it more than high fuel costs.

>>
>>>>>> A lot of people don't like
>>>>>> them at all, but others say they get used to it. (The perception
>>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>>> them thereby defeating the chief advantage of the CVT.)
>>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>>> quite fun! this particular model had 2 independent drives too, so not
>>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>>> snow & ice too.
>>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>>> That was the original CVT. Do you remember who offered the first CVT
>>>> in the US. (I don't think they ever sold the Daffodil here.)
>>> subaru?
>>
>> That is what I recall. The car was called the Justy.
>>
>>>>>> I only rode
>>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>>> know if I would like it or not.
>>>>> if you're not used to traditional automatics, the transition is easy.
>>>>> if you're used to traditional autos, its weird for a few minutes because
>>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>>> Again though, I am not sure they are any faster or more efficient than
>>>> a good MT.
>>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>>
>> I think the Honda 600 would have blown its petals off. ;-)
>>
>>>> Consumer Reports tested the Versa with MT and with CVT.
>>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>>> CR panned that MT.) They also tested MT and (conventional) AT
>>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>>> that depends on the management system. the modern cvt's "simulate" gear
>>> shifts which is the dumbest damned thing since it's not utilizing the
>>> inherent benefit of the system! on that basis, i'm not surprised.
>>
>> Does the Versa do that? CR didn't mention it.
>
>don't know. given "consumer demand", i expect so.

Like I said, they hate it just like you think I would. (Actually I
would love to try one, I do think it is a neat idea and it would be
fun for a while at least. Only after the novelty wore off could I
tell you if I like it or hate it. I actually suspect that I would
like it more than a conventional AT.)

Here is an interesting review I found. (It indicates that the Versa
CVT does not have "gears," so the fact that it was slower and less
fuel efficient than the "clunky" MT is significant.) I made one
editorial comment in brackets.

--quote--
But the CVT is the one that shines. Its proprietary design, benefiting
from Nissan's global cooperation with French carmaker Renault, is
uncanny in the way it maintains optimal engine rpm within the most
fuel-efficient torque range. It senses, for example, when the Versa is
proceeding downhill and glides effortlessly into a lower gear range to
slow the car with engine braking. [What if you don't want engine
braking? It is wasting kinetic energy = fuel. What it needs in a
powerful computer with optical sensors to look ahead, evaluate the
situation and decide whether engine braking is advantageous.]
Conversely, under pedal-to-the-floor acceleration, the CVT instantly
launches the engine to its max-torque rpm, then keeps it there
unchanged until a desired highway speed is reached.

This goes against every traditional sensation of driving, wherein gear
changes trigger a momentary drop in rpm as the higher gear ratio is
engaged. There's a lot of mechanical inefficiency in that traditional
gear-change syncopation; and Versa's CVT eliminates it. When first
experiencing the CVT's behavior, it feels wrong, sounds noisy. In
truth, however, it's mostly the lack of noticeable gear changes that's
merely thwarting a driver's subconscious expectation of rising-falling
rpms as gears change.
--end quote--

http://www.carlist.com/newcars/2007/ncr1116.html


>>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>>> of them seem to be on hybrids in fact.
>>> that's consumer and mechanic inertia - nothing to do with benefits or
>>> reliability. trust me on that one - i've driven the daf for an extended
>>> period and it's a great system.
>>
>> Maybe. I would gladly trade the AT in my Ody for one if it was proven
>> reliable. Not all are. The on in the Saturn Vue was a disaster, but
>> I guess you have to expect that from GM. The Japanese units don't
>> seem to have any problems.
>
>i've never heard of problems with the civic hx.

Neither have I, but then there aren't a lot out there.

 

On Mon, 08 Jan 2007 21:25:13 -0800, jim beam
<spamvortex@bad.example.net> wrote:

>Gordon McGrew wrote:
>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>> <spamvortex@bad.example.net> wrote:
>>
>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>> /can/ flip up and down at will.
>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>> on braking. not gentle braking, but harder braking.
>>>> It is not a bad thing, I just don't care for it. If I want to
>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>> doing it on its own.
>>> why not? it's just like you'd have on a stick.
>>
>> Not sure I understand. My GS-R never downshifts on its own.
>
>if it doesn't, then there's something wrong. how old is it?

It is a '94 with a 5-speed manual transmission. What kind of MT cars
have you driven that shift themselves???


>
>>
>>>>>> When you
>>>>>> shift into 3 does it effectively double clutch?
>>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>>> meshed to the gear on shift.
>>>> That is what I mean. I figured they had fixed that aspect which is
>>>> the worst part of the older ATs.
>>>>
>>>>>>>> Also, I
>>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>>> much smoother of course]?
>>>>>> Well, as you point out, I don't have any experience with modern high
>>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>>> they now mostly have five gears, I would assume that means they are
>>>>>> slipping.
>>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>>
>>>>>> Actually, the slipping is partly by design, the so-called
>>>>>> torque multiplier effect.
>>>>> yes, that's what a torque converter does.
>>>>>
>>>>>> Basically, if you are cruising along and
>>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>>> will see the rpms jump up immediately.
>>>>> that's because the lockup clutch is released to allow more torque. more
>>>>> flexibility than a stick where you'd have to shift.
>>>> But that is the slippage. The engine speeds up races up ahead of any
>>>> change in vehicle speed.
>>> but i don't understand the problem - what's wrong with it? engines are
>>> not perfect across all rev ranges - why not let a computer manage the
>>> efficiency curves - for that's what's happening.
>>
>> It is just a personal preference. I like the engine to be positively
>> coupled to the wheels.
>
>that's what the lockup clutch in the torque converter is for.

But it isn't engaged all the time. When it disengages, that is when
it "slips" and I do not find that satisfying as a driver. Like I said
a the outside, it is a preference for MT. I like to drive cars and
the MT is more enjoyable than the ATs I have driven. I don't like it
shifting when I don't want it to and I don't like the slippy feel of
the torque converter. The fact that the MT is usually faster and more
fuel efficient is a bonus.


>
>>
>>>> It is like a slipping clutch. As for more
>>>> torque (horsepower really) a lot of that is eaten up by the
>>>> inefficiency of the torque converter.
>>> how is a slipping clutch more efficient? [it's not.]
>>
>> No, I understand that (unlike a slipping clutch) there is a benefit to
>> the slip designed into the AT. I just don't like the feel of it and
>> the benefit is more than eaten up by the inefficiencies that come with
>> it.
>
>you'd hate cvt. there's no "relationship" between revs and engine speed
>at all.

I think you are probably right. That is why I mentioned the fact that
the CVT isn't very popular in the US (if anywhere) and I think it is
because lots of people hate it. Why else would Honda sell a 7-speed
CVT?

OTOH, it probably appeals to - or at least doesn't repulse - the
hybrid buyer because it befits the unconventional nature of the car. I
realize there are technical benefits to the combination of hybrid and
CVT, but I am saying that the unconventional nature of the CVT is less
of a negative when you are already committed to buying an
unconventional vehicle. If you are attracted to the hybrid because it
is unconventional, the CVT is a plus.

>>>> On cars where you can get a MT
>>>> or AT with the same engine, the MT is almost always faster and gets
>>>> better mileage.
>>> not so with the modern autos. and that's one of the big things about
>>> honda autos - it's basically a standard transmission with clutch packs
>>> instead of synchros. inherently more efficient than planetary gears.
>>
>> Looking at the differences between the ATs in the econo cars tested by
>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>
>you're looking at fuel economy, right?

Fuel economy was significantly better for the MTs but the biggest
difference was acceleration. The MTs blew the doors off the ATs. In
terms of 0 - 60 time differences, the Yaris AT was the best - "only"
2.1 seconds slower than the MT version. Even the slowest MT car, the
Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
was 1.4 seconds slower than the Versa CVT.

>>
>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>> that's different - it's not a torque multiplier.
>>>> Neither is the conventional AT, it just has a clever design to let the
>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>> basically like a limited range CVT.
>>> no dude, they're totally different. "torque multiplier" is something a
>>> torque converter can do - hence its name. everything else is ratio
>>> control, be it continuously variable or discrete.
>>
>> OK, explain it to me. My understanding is that it is just a trick to
>> get the engine running at a slightly higher rpm to produce more power.
>> Kind of like a mini downshift. All car transmissions are torque
>> multipliers.
>
>ok, yes, but we're talking about different things. torque converters
>can increase torque output from a little to a lot in a very limited rev
>range. ratio change is something different and that's what the gears
>are for.

You understand that the ATs torque output at a certain rpm (i.e. power
transmitted) is higher when the torque multiplication is active. There
are only two way this can happen. The first is to increase the
efficiency of the transmission. I think we can dismiss that. The
other way is to increase the power input. The only way to do that is
to increase the throttle opening or increase the rpm. The throttle
opening is determined by your foot (and it wouldn't be much of a trick
for the torque multiplier to be just an extra jerk on the throttle and
it wouldn't do much good if the throttle were already wide open.)
However, rpm is largely controlled by the transmission. The
transmission allows the engine to run a little faster and therefore
produce more power which is transmitted to the wheels. This is what I
meant by a mini downshift.

>> They take high rpm/low torque and turn it into low rpm
>> high torque. If it were perfectly efficient, the power output would
>> be equal to input but of course it is always less. No way to get more
>> power out unless you put more power in, i.e. run the engine at higher
>> rpm.
>
>see above.
>
>>
>>>>> if is however a great
>>>>> way of achieving absolute optimum gear for all conditions.
>>>> I agree that it has a big theoretical advantage, especially compared
>>>> to a conventional AT.
>>> compared to /any/ transmission. there are mechanical efficiency issues
>>> with the friction interface, but that is more than outweighed by ratio
>>> flexibility and ability to keep the engine at its most efficient.
>>
>> The why doesn't the Versa with a CVT get better mileage or accelerate
>> faster than the Versa with an MT? Unfortunately, there are few cars
>> which allow you to directly compare CVT vs. MT.
>
>civic hx was significantly more fuel efficient than the stick.

I gather that was the CVT-equipped model. They don't sell it anymore.
I guess people hated it more than high fuel costs.

>>
>>>>>> A lot of people don't like
>>>>>> them at all, but others say they get used to it. (The perception
>>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>>> them thereby defeating the chief advantage of the CVT.)
>>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>>> quite fun! this particular model had 2 independent drives too, so not
>>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>>> snow & ice too.
>>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>>> That was the original CVT. Do you remember who offered the first CVT
>>>> in the US. (I don't think they ever sold the Daffodil here.)
>>> subaru?
>>
>> That is what I recall. The car was called the Justy.
>>
>>>>>> I only rode
>>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>>> know if I would like it or not.
>>>>> if you're not used to traditional automatics, the transition is easy.
>>>>> if you're used to traditional autos, its weird for a few minutes because
>>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>>> Again though, I am not sure they are any faster or more efficient than
>>>> a good MT.
>>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>>
>> I think the Honda 600 would have blown its petals off. ;-)
>>
>>>> Consumer Reports tested the Versa with MT and with CVT.
>>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>>> CR panned that MT.) They also tested MT and (conventional) AT
>>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>>> that depends on the management system. the modern cvt's "simulate" gear
>>> shifts which is the dumbest damned thing since it's not utilizing the
>>> inherent benefit of the system! on that basis, i'm not surprised.
>>
>> Does the Versa do that? CR didn't mention it.
>
>don't know. given "consumer demand", i expect so.

Like I said, they hate it just like you think I would. (Actually I
would love to try one, I do think it is a neat idea and it would be
fun for a while at least. Only after the novelty wore off could I
tell you if I like it or hate it. I actually suspect that I would
like it more than a conventional AT.)

Here is an interesting review I found. (It indicates that the Versa
CVT does not have "gears," so the fact that it was slower and less
fuel efficient than the "clunky" MT is significant.) I made one
editorial comment in brackets.

--quote--
But the CVT is the one that shines. Its proprietary design, benefiting
from Nissan's global cooperation with French carmaker Renault, is
uncanny in the way it maintains optimal engine rpm within the most
fuel-efficient torque range. It senses, for example, when the Versa is
proceeding downhill and glides effortlessly into a lower gear range to
slow the car with engine braking. [What if you don't want engine
braking? It is wasting kinetic energy = fuel. What it needs in a
powerful computer with optical sensors to look ahead, evaluate the
situation and decide whether engine braking is advantageous.]
Conversely, under pedal-to-the-floor acceleration, the CVT instantly
launches the engine to its max-torque rpm, then keeps it there
unchanged until a desired highway speed is reached.

This goes against every traditional sensation of driving, wherein gear
changes trigger a momentary drop in rpm as the higher gear ratio is
engaged. There's a lot of mechanical inefficiency in that traditional
gear-change syncopation; and Versa's CVT eliminates it. When first
experiencing the CVT's behavior, it feels wrong, sounds noisy. In
truth, however, it's mostly the lack of noticeable gear changes that's
merely thwarting a driver's subconscious expectation of rising-falling
rpms as gears change.
--end quote--

http://www.carlist.com/newcars/2007/ncr1116.html


>>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>>> of them seem to be on hybrids in fact.
>>> that's consumer and mechanic inertia - nothing to do with benefits or
>>> reliability. trust me on that one - i've driven the daf for an extended
>>> period and it's a great system.
>>
>> Maybe. I would gladly trade the AT in my Ody for one if it was proven
>> reliable. Not all are. The on in the Saturn Vue was a disaster, but
>> I guess you have to expect that from GM. The Japanese units don't
>> seem to have any problems.
>
>i've never heard of problems with the civic hx.

Neither have I, but then there aren't a lot out there.

 

Gordon McGrew wrote:
> On Mon, 08 Jan 2007 21:25:13 -0800, jim beam
> <spamvortex@bad.example.net> wrote:
>
>> Gordon McGrew wrote:
>>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>>> <spamvortex@bad.example.net> wrote:
>>>
>>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>>> /can/ flip up and down at will.
>>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>>> on braking. not gentle braking, but harder braking.
>>>>> It is not a bad thing, I just don't care for it. If I want to
>>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>>> doing it on its own.
>>>> why not? it's just like you'd have on a stick.
>>> Not sure I understand. My GS-R never downshifts on its own.
>> if it doesn't, then there's something wrong. how old is it?
>
> It is a '94 with a 5-speed manual transmission. What kind of MT cars
> have you driven that shift themselves???

i misunderstood you.

originally, you said "If I want to downshift, I can do that." well, you
can on an auto. on my car, the shifter is in the same place as a stick
would be too. and the auto replicates engine braking when you need it -
just like you'd do yourself. really, it's a good system.

>
>
>>>>>>> When you
>>>>>>> shift into 3 does it effectively double clutch?
>>>>>> pointless exercise on an automatic. but even then, on the modern autos,
>>>>>> in conjunction with electronic throttle, yes, the engine revs /are/
>>>>>> meshed to the gear on shift.
>>>>> That is what I mean. I figured they had fixed that aspect which is
>>>>> the worst part of the older ATs.
>>>>>
>>>>>>>>> Also, I
>>>>>>>>> don't particularly care for the slippage of the torque converter.
>>>>>>>> eh? what "slippage" is that? how does its mechanical function differ
>>>>>>> >from a clutch [other than it has a much better efficiency range and is
>>>>>>>> much smoother of course]?
>>>>>>> Well, as you point out, I don't have any experience with modern high
>>>>>>> end luxury cars, but I note that at least more modest cars generally
>>>>>>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>>>>>>> they now mostly have five gears, I would assume that means they are
>>>>>>> slipping.
>>>>>> there's no slipping unless the lock-up clutch is released. see below.
>>>>>>
>>>>>>> Actually, the slipping is partly by design, the so-called
>>>>>>> torque multiplier effect.
>>>>>> yes, that's what a torque converter does.
>>>>>>
>>>>>>> Basically, if you are cruising along and
>>>>>>> you give it a little gas, but not enough to force a downshift, you
>>>>>>> will see the rpms jump up immediately.
>>>>>> that's because the lockup clutch is released to allow more torque. more
>>>>>> flexibility than a stick where you'd have to shift.
>>>>> But that is the slippage. The engine speeds up races up ahead of any
>>>>> change in vehicle speed.
>>>> but i don't understand the problem - what's wrong with it? engines are
>>>> not perfect across all rev ranges - why not let a computer manage the
>>>> efficiency curves - for that's what's happening.
>>> It is just a personal preference. I like the engine to be positively
>>> coupled to the wheels.
>> that's what the lockup clutch in the torque converter is for.
>
> But it isn't engaged all the time. When it disengages, that is when
> it "slips" and I do not find that satisfying as a driver.

you'd hate cvt. as i said before, there's zero relation between engine
speed and vehicle speed - if you drive on engine revs, and it sounds
like you do, you'll be suffering total loss of feedback.

> Like I said
> a the outside, it is a preference for MT. I like to drive cars and
> the MT is more enjoyable than the ATs I have driven. I don't like it
> shifting when I don't want it to and I don't like the slippy feel of
> the torque converter. The fact that the MT is usually faster and more
> fuel efficient is a bonus.

check the modern civics in that department.

>
>
>>>>> It is like a slipping clutch. As for more
>>>>> torque (horsepower really) a lot of that is eaten up by the
>>>>> inefficiency of the torque converter.
>>>> how is a slipping clutch more efficient? [it's not.]
>>> No, I understand that (unlike a slipping clutch) there is a benefit to
>>> the slip designed into the AT. I just don't like the feel of it and
>>> the benefit is more than eaten up by the inefficiencies that come with
>>> it.
>> you'd hate cvt. there's no "relationship" between revs and engine speed
>> at all.
>
> I think you are probably right. That is why I mentioned the fact that
> the CVT isn't very popular in the US (if anywhere) and I think it is
> because lots of people hate it. Why else would Honda sell a 7-speed
> CVT?

because they rely on dealer feedback, and dealers are morons? cvt was
pretty popular in europe iirc. volvo sold them as well as daf, and they
did quite well.

>
> OTOH, it probably appeals to - or at least doesn't repulse - the
> hybrid buyer because it befits the unconventional nature of the car. I
> realize there are technical benefits to the combination of hybrid and
> CVT, but I am saying that the unconventional nature of the CVT is less
> of a negative when you are already committed to buying an
> unconventional vehicle. If you are attracted to the hybrid because it
> is unconventional, the CVT is a plus.

nah, it's a pure engineering logic decision. cvt allows extremely good
engine efficiency. if you don't want that, you don't want a hybrid.

>
>>>>> On cars where you can get a MT
>>>>> or AT with the same engine, the MT is almost always faster and gets
>>>>> better mileage.
>>>> not so with the modern autos. and that's one of the big things about
>>>> honda autos - it's basically a standard transmission with clutch packs
>>>> instead of synchros. inherently more efficient than planetary gears.
>>> Looking at the differences between the ATs in the econo cars tested by
>>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>> you're looking at fuel economy, right?
>
> Fuel economy was significantly better for the MTs but the biggest
> difference was acceleration. The MTs blew the doors off the ATs. In
> terms of 0 - 60 time differences, the Yaris AT was the best - "only"
> 2.1 seconds slower than the MT version. Even the slowest MT car, the
> Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
> was 1.4 seconds slower than the Versa CVT.

dude, compare like with like - not different car to different car if
you're trying to compare trnasmissions, i.e. yaris with cvt, yaris with
stick, etc. yaris stick to versa cvt doesn't work.

>
>>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>>> that's different - it's not a torque multiplier.
>>>>> Neither is the conventional AT, it just has a clever design to let the
>>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>>> basically like a limited range CVT.
>>>> no dude, they're totally different. "torque multiplier" is something a
>>>> torque converter can do - hence its name. everything else is ratio
>>>> control, be it continuously variable or discrete.
>>> OK, explain it to me. My understanding is that it is just a trick to
>>> get the engine running at a slightly higher rpm to produce more power.
>>> Kind of like a mini downshift. All car transmissions are torque
>>> multipliers.
>> ok, yes, but we're talking about different things. torque converters
>> can increase torque output from a little to a lot in a very limited rev
>> range. ratio change is something different and that's what the gears
>> are for.
>
> You understand that the ATs torque output at a certain rpm (i.e. power
> transmitted) is higher when the torque multiplication is active. There
> are only two way this can happen. The first is to increase the
> efficiency of the transmission. I think we can dismiss that. The
> other way is to increase the power input.

no, it depends on input/output speed differential. within certain rev
ranges, torque transmission is very high, even with a rev differential.
if it gets outside of that band, it drops right off.

> The only way to do that is
> to increase the throttle opening or increase the rpm. The throttle
> opening is determined by your foot (and it wouldn't be much of a trick
> for the torque multiplier to be just an extra jerk on the throttle and
> it wouldn't do much good if the throttle were already wide open.)
> However, rpm is largely controlled by the transmission. The
> transmission allows the engine to run a little faster and therefore
> produce more power which is transmitted to the wheels. This is what I
> meant by a mini downshift.

that's the lockup clutch releasing.

>
>>> They take high rpm/low torque and turn it into low rpm
>>> high torque. If it were perfectly efficient, the power output would
>>> be equal to input but of course it is always less. No way to get more
>>> power out unless you put more power in, i.e. run the engine at higher
>>> rpm.
>> see above.
>>
>>>>>> if is however a great
>>>>>> way of achieving absolute optimum gear for all conditions.
>>>>> I agree that it has a big theoretical advantage, especially compared
>>>>> to a conventional AT.
>>>> compared to /any/ transmission. there are mechanical efficiency issues
>>>> with the friction interface, but that is more than outweighed by ratio
>>>> flexibility and ability to keep the engine at its most efficient.
>>> The why doesn't the Versa with a CVT get better mileage or accelerate
>>> faster than the Versa with an MT? Unfortunately, there are few cars
>>> which allow you to directly compare CVT vs. MT.
>> civic hx was significantly more fuel efficient than the stick.
>
> I gather that was the CVT-equipped model. They don't sell it anymore.
> I guess people hated it more than high fuel costs.

my money's on dealer prejudice, not consumer. by the same token, the
hatchback has been all but dropped in the u.s. afaikt, that's more to
do with vehicles with the same utility selling for $30k rather than $15k
for a hatch, not consumer demand. try buying a used hatchback civic
here in the bay area - good luck! people just keep them - they never
sell.

>
>>>>>>> A lot of people don't like
>>>>>>> them at all, but others say they get used to it. (The perception
>>>>>>> problem is so bad that some manufacturers program virtual gears into
>>>>>>> them thereby defeating the chief advantage of the CVT.)
>>>>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>>>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>>>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>>>>> quite fun! this particular model had 2 independent drives too, so not
>>>>>> only did you have optimum gearing, you had limited slip diff benefits in
>>>>>> snow & ice too.
>>>>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>>>> That was the original CVT. Do you remember who offered the first CVT
>>>>> in the US. (I don't think they ever sold the Daffodil here.)
>>>> subaru?
>>> That is what I recall. The car was called the Justy.
>>>
>>>>>>> I only rode
>>>>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>>>>> that application. He drove it fairly aggressively too - we hit almost
>>>>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>>>>> know if I would like it or not.
>>>>>> if you're not used to traditional automatics, the transition is easy.
>>>>>> if you're used to traditional autos, its weird for a few minutes because
>>>>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>>>> Again though, I am not sure they are any faster or more efficient than
>>>>> a good MT.
>>>> well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
>>> I think the Honda 600 would have blown its petals off. ;-)
>>>
>>>>> Consumer Reports tested the Versa with MT and with CVT.
>>>>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>>>>> CR panned that MT.) They also tested MT and (conventional) AT
>>>>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>>>>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>>>>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>>>> that depends on the management system. the modern cvt's "simulate" gear
>>>> shifts which is the dumbest damned thing since it's not utilizing the
>>>> inherent benefit of the system! on that basis, i'm not surprised.
>>> Does the Versa do that? CR didn't mention it.
>> don't know. given "consumer demand", i expect so.
>
> Like I said, they hate it just like you think I would. (Actually I
> would love to try one, I do think it is a neat idea and it would be
> fun for a while at least. Only after the novelty wore off could I
> tell you if I like it or hate it. I actually suspect that I would
> like it more than a conventional AT.)
>
> Here is an interesting review I found. (It indicates that the Versa
> CVT does not have "gears," so the fact that it was slower and less
> fuel efficient than the "clunky" MT is significant.) I made one
> editorial comment in brackets.
>
> --quote--
> But the CVT is the one that shines. Its proprietary design, benefiting
> from Nissan's global cooperation with French carmaker Renault, is
> uncanny in the way it maintains optimal engine rpm within the most
> fuel-efficient torque range. It senses, for example, when the Versa is
> proceeding downhill and glides effortlessly into a lower gear range to
> slow the car with engine braking. [What if you don't want engine
> braking? It is wasting kinetic energy = fuel.

not correct. when engine braking, fuel delivery is completely stopped.

> What it needs in a
> powerful computer with optical sensors to look ahead, evaluate the
> situation and decide whether engine braking is advantageous

why? i don't want my car making /that/ kind of decision. seriously,
auto engine braking only happens when you're foot braking - just like on
a stick. you can't criticize what you've not used dude.

>.]
> Conversely, under pedal-to-the-floor acceleration, the CVT instantly
> launches the engine to its max-torque rpm, then keeps it there
> unchanged until a desired highway speed is reached.
>
> This goes against every traditional sensation of driving, wherein gear
> changes trigger a momentary drop in rpm as the higher gear ratio is
> engaged. There's a lot of mechanical inefficiency in that traditional
> gear-change syncopation; and Versa's CVT eliminates it. When first
> experiencing the CVT's behavior, it feels wrong, sounds noisy. In
> truth, however, it's mostly the lack of noticeable gear changes that's
> merely thwarting a driver's subconscious expectation of rising-falling
> rpms as gears change.
> --end quote--
>
> http://www.carlist.com/newcars/2007/ncr1116.html
>
>
>>>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>>>> of them seem to be on hybrids in fact.
>>>> that's consumer and mechanic inertia - nothing to do with benefits or
>>>> reliability. trust me on that one - i've driven the daf for an extended
>>>> period and it's a great system.
>>> Maybe. I would gladly trade the AT in my Ody for one if it was proven
>>> reliable. Not all are. The on in the Saturn Vue was a disaster, but
>>> I guess you have to expect that from GM. The Japanese units don't
>>> seem to have any problems.
>> i've never heard of problems with the civic hx.
>
> Neither have I, but then there aren't a lot out there.

/all/ the 96-2000 hx autos are cvt.