automatic car
11-17-2006 | 01:11 PM
#31
Guest
Posts: n/a
Re: automatic car
jim beam wrote:
> John Horner wrote:
>> Philip Tang wrote:
>>> I drive a honda accord (automatic), and a friend of mine advised me that
>>> when I am driving downhill, I should shift the gear to 3rd gear from
>>> D. If
>>> I do it everyday, 5-6 times daily, will it lower the performance of
>>> the car
>>> (gearbox) ? Or am I simply doing the right thing as anyone should be
>>> doing?
>>>
>>> Philip
>>>
>>>
>>>
>>
>> I have never understood the recommendation to use engine/transmission
>> braking instead of the regular brakes to slow a car down. I would
>> much rather change brake pads than I would repair internal clutch
>> packs in an automatic transmission.
>
Every extra shift is extra wear.
Engine braking also puts load on the bearings and rings for no
productive purpose. Heck, it even puts strain on the throttle butterfly
bushings.
> using the engine is "free" braking. using the brakes is not. once the
> pads get hot, efficiency decreases, and in extreme cases, fade to almost
> nothing. needless to say, you don't want that. [ask any truck driver
> that's used the emergency run-off ramps on grapevine in southern
> california - i drive through once or twice a month, and every time
> there's a truck either in, just towed off, or the evidence of a fresh
> brake failure on those ramps.]
>
For ultra heavy trucks this is of course an entirely different discussion.
For passenger cars in normal use, not trailering and now packed to the
gills, the extra shifting is to no benefit.
John
> John Horner wrote:
>> Philip Tang wrote:
>>> I drive a honda accord (automatic), and a friend of mine advised me that
>>> when I am driving downhill, I should shift the gear to 3rd gear from
>>> D. If
>>> I do it everyday, 5-6 times daily, will it lower the performance of
>>> the car
>>> (gearbox) ? Or am I simply doing the right thing as anyone should be
>>> doing?
>>>
>>> Philip
>>>
>>>
>>>
>>
>> I have never understood the recommendation to use engine/transmission
>> braking instead of the regular brakes to slow a car down. I would
>> much rather change brake pads than I would repair internal clutch
>> packs in an automatic transmission.
>
Every extra shift is extra wear.
Engine braking also puts load on the bearings and rings for no
productive purpose. Heck, it even puts strain on the throttle butterfly
bushings.
> using the engine is "free" braking. using the brakes is not. once the
> pads get hot, efficiency decreases, and in extreme cases, fade to almost
> nothing. needless to say, you don't want that. [ask any truck driver
> that's used the emergency run-off ramps on grapevine in southern
> california - i drive through once or twice a month, and every time
> there's a truck either in, just towed off, or the evidence of a fresh
> brake failure on those ramps.]
>
For ultra heavy trucks this is of course an entirely different discussion.
For passenger cars in normal use, not trailering and now packed to the
gills, the extra shifting is to no benefit.
John
11-18-2006 | 09:28 PM
#32
Guest
Posts: n/a
Re: automatic car
On Thu, 16 Nov 2006 16:52:18 +0800, "Philip Tang"
<philtang1001@netvigator.com> wrote:
>I drive a honda accord (automatic), and a friend of mine advised me that
>when I am driving downhill, I should shift the gear to 3rd gear from D. If
>I do it everyday, 5-6 times daily, will it lower the performance of the car
>(gearbox) ? Or am I simply doing the right thing as anyone should be doing?
Recent Accords have "hill logic", or something like that, which has
both uphill and downhill features, including some engine braking, as I
understand it.
I agree with John, in any case you'd much rather use up some brake
pads then ask your aluminum-block engine to rev hard and slow you
down. If your car is less than five years old, I'd leave it in drive.
For that matter, if your car is older than five years, I'd still leave
it in drive!
J.
<philtang1001@netvigator.com> wrote:
>I drive a honda accord (automatic), and a friend of mine advised me that
>when I am driving downhill, I should shift the gear to 3rd gear from D. If
>I do it everyday, 5-6 times daily, will it lower the performance of the car
>(gearbox) ? Or am I simply doing the right thing as anyone should be doing?
Recent Accords have "hill logic", or something like that, which has
both uphill and downhill features, including some engine braking, as I
understand it.
I agree with John, in any case you'd much rather use up some brake
pads then ask your aluminum-block engine to rev hard and slow you
down. If your car is less than five years old, I'd leave it in drive.
For that matter, if your car is older than five years, I'd still leave
it in drive!
J.
11-18-2006 | 09:28 PM
#33
Guest
Posts: n/a
Re: automatic car
On Thu, 16 Nov 2006 16:52:18 +0800, "Philip Tang"
<philtang1001@netvigator.com> wrote:
>I drive a honda accord (automatic), and a friend of mine advised me that
>when I am driving downhill, I should shift the gear to 3rd gear from D. If
>I do it everyday, 5-6 times daily, will it lower the performance of the car
>(gearbox) ? Or am I simply doing the right thing as anyone should be doing?
Recent Accords have "hill logic", or something like that, which has
both uphill and downhill features, including some engine braking, as I
understand it.
I agree with John, in any case you'd much rather use up some brake
pads then ask your aluminum-block engine to rev hard and slow you
down. If your car is less than five years old, I'd leave it in drive.
For that matter, if your car is older than five years, I'd still leave
it in drive!
J.
<philtang1001@netvigator.com> wrote:
>I drive a honda accord (automatic), and a friend of mine advised me that
>when I am driving downhill, I should shift the gear to 3rd gear from D. If
>I do it everyday, 5-6 times daily, will it lower the performance of the car
>(gearbox) ? Or am I simply doing the right thing as anyone should be doing?
Recent Accords have "hill logic", or something like that, which has
both uphill and downhill features, including some engine braking, as I
understand it.
I agree with John, in any case you'd much rather use up some brake
pads then ask your aluminum-block engine to rev hard and slow you
down. If your car is less than five years old, I'd leave it in drive.
For that matter, if your car is older than five years, I'd still leave
it in drive!
J.
11-18-2006 | 09:28 PM
#34
Guest
Posts: n/a
Re: automatic car
On Thu, 16 Nov 2006 16:52:18 +0800, "Philip Tang"
<philtang1001@netvigator.com> wrote:
>I drive a honda accord (automatic), and a friend of mine advised me that
>when I am driving downhill, I should shift the gear to 3rd gear from D. If
>I do it everyday, 5-6 times daily, will it lower the performance of the car
>(gearbox) ? Or am I simply doing the right thing as anyone should be doing?
Recent Accords have "hill logic", or something like that, which has
both uphill and downhill features, including some engine braking, as I
understand it.
I agree with John, in any case you'd much rather use up some brake
pads then ask your aluminum-block engine to rev hard and slow you
down. If your car is less than five years old, I'd leave it in drive.
For that matter, if your car is older than five years, I'd still leave
it in drive!
J.
<philtang1001@netvigator.com> wrote:
>I drive a honda accord (automatic), and a friend of mine advised me that
>when I am driving downhill, I should shift the gear to 3rd gear from D. If
>I do it everyday, 5-6 times daily, will it lower the performance of the car
>(gearbox) ? Or am I simply doing the right thing as anyone should be doing?
Recent Accords have "hill logic", or something like that, which has
both uphill and downhill features, including some engine braking, as I
understand it.
I agree with John, in any case you'd much rather use up some brake
pads then ask your aluminum-block engine to rev hard and slow you
down. If your car is less than five years old, I'd leave it in drive.
For that matter, if your car is older than five years, I'd still leave
it in drive!
J.
11-18-2006 | 09:57 PM
#38
Guest
Posts: n/a
Re: automatic car
Robert wrote:
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
that is about the worst thing you can do.
in order of darwin award qualification:
1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.
again, you are NOT saving gas in neutral - in fact, just the opposite.
fuel injected systems do not inject gas if coasting *above* a given rpm,
[say 1,500], so you coasting and allowing the revs to drop below that
limit ensures the engine has to keep having fuel injected.
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
that is about the worst thing you can do.
in order of darwin award qualification:
1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.
again, you are NOT saving gas in neutral - in fact, just the opposite.
fuel injected systems do not inject gas if coasting *above* a given rpm,
[say 1,500], so you coasting and allowing the revs to drop below that
limit ensures the engine has to keep having fuel injected.
11-18-2006 | 09:57 PM
#39
Guest
Posts: n/a
Re: automatic car
Robert wrote:
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
that is about the worst thing you can do.
in order of darwin award qualification:
1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.
again, you are NOT saving gas in neutral - in fact, just the opposite.
fuel injected systems do not inject gas if coasting *above* a given rpm,
[say 1,500], so you coasting and allowing the revs to drop below that
limit ensures the engine has to keep having fuel injected.
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
that is about the worst thing you can do.
in order of darwin award qualification:
1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.
again, you are NOT saving gas in neutral - in fact, just the opposite.
fuel injected systems do not inject gas if coasting *above* a given rpm,
[say 1,500], so you coasting and allowing the revs to drop below that
limit ensures the engine has to keep having fuel injected.
11-18-2006 | 09:57 PM
#40
Guest
Posts: n/a
Re: automatic car
Robert wrote:
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
that is about the worst thing you can do.
in order of darwin award qualification:
1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.
again, you are NOT saving gas in neutral - in fact, just the opposite.
fuel injected systems do not inject gas if coasting *above* a given rpm,
[say 1,500], so you coasting and allowing the revs to drop below that
limit ensures the engine has to keep having fuel injected.
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
that is about the worst thing you can do.
in order of darwin award qualification:
1. your brakes are much hotter than they need to be.
2. you don't have the engine engaged in case you need it.
3. you're burning more gas than coasting in gear.
4. in some states, coasting in neutral is illegal.
again, you are NOT saving gas in neutral - in fact, just the opposite.
fuel injected systems do not inject gas if coasting *above* a given rpm,
[say 1,500], so you coasting and allowing the revs to drop below that
limit ensures the engine has to keep having fuel injected.
11-18-2006 | 10:16 PM
#41
Guest
Posts: n/a
Re: automatic car
jim beam wrote:
>
> Robert wrote:
> > Looking at it from another standpoint (saving gas), I put my car in
> > neutral down long hills and just use the brakes. Never had a problem.
> >
> that is about the worst thing you can do.
>
> in order of darwin award qualification:
> 1. your brakes are much hotter than they need to be.
> 2. you don't have the engine engaged in case you need it.
> 3. you're burning more gas than coasting in gear.
> 4. in some states, coasting in neutral is illegal.
>
> again, you are NOT saving gas in neutral - in fact, just the opposite.
> fuel injected systems do not inject gas if coasting *above* a given rpm,
> [say 1,500], so you coasting and allowing the revs to drop below that
> limit ensures the engine has to keep having fuel injected.
Heh... Maybe he rides the clutch to compensate...
<G>
JT
11-18-2006 | 10:16 PM
#42
Guest
Posts: n/a
Re: automatic car
jim beam wrote:
>
> Robert wrote:
> > Looking at it from another standpoint (saving gas), I put my car in
> > neutral down long hills and just use the brakes. Never had a problem.
> >
> that is about the worst thing you can do.
>
> in order of darwin award qualification:
> 1. your brakes are much hotter than they need to be.
> 2. you don't have the engine engaged in case you need it.
> 3. you're burning more gas than coasting in gear.
> 4. in some states, coasting in neutral is illegal.
>
> again, you are NOT saving gas in neutral - in fact, just the opposite.
> fuel injected systems do not inject gas if coasting *above* a given rpm,
> [say 1,500], so you coasting and allowing the revs to drop below that
> limit ensures the engine has to keep having fuel injected.
Heh... Maybe he rides the clutch to compensate...
<G>
JT
11-18-2006 | 10:16 PM
#43
Guest
Posts: n/a
Re: automatic car
jim beam wrote:
>
> Robert wrote:
> > Looking at it from another standpoint (saving gas), I put my car in
> > neutral down long hills and just use the brakes. Never had a problem.
> >
> that is about the worst thing you can do.
>
> in order of darwin award qualification:
> 1. your brakes are much hotter than they need to be.
> 2. you don't have the engine engaged in case you need it.
> 3. you're burning more gas than coasting in gear.
> 4. in some states, coasting in neutral is illegal.
>
> again, you are NOT saving gas in neutral - in fact, just the opposite.
> fuel injected systems do not inject gas if coasting *above* a given rpm,
> [say 1,500], so you coasting and allowing the revs to drop below that
> limit ensures the engine has to keep having fuel injected.
Heh... Maybe he rides the clutch to compensate...
<G>
JT
11-19-2006 | 12:00 AM
#44
Guest
Posts: n/a
Re: automatic car
"Robert" <kraft.fhs@gmail.com> wrote in message
news:1163904215.591388.163320@h48g2000cwc.googlegr oups.com...
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
With disc brakes it isn't as big a problem, but I remember driving our
family '67 Chevy with 4-wheel drums down a long descent somewhere near Bonny
Doon, CA. I had the two-speed automatic in low gear (top speed about 55 mph)
and within a few minutes I had both feet braced hard on the brake pedal
continuously. I was lucky to find a flat spot where could I pull off. I
tried to let the brakes cool, but after 15 minutes they still had no
significant effect. I got rolling slowly and they cooled enough to keep my
speed under 40 mph. It was pretty scary.
Mike
news:1163904215.591388.163320@h48g2000cwc.googlegr oups.com...
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
With disc brakes it isn't as big a problem, but I remember driving our
family '67 Chevy with 4-wheel drums down a long descent somewhere near Bonny
Doon, CA. I had the two-speed automatic in low gear (top speed about 55 mph)
and within a few minutes I had both feet braced hard on the brake pedal
continuously. I was lucky to find a flat spot where could I pull off. I
tried to let the brakes cool, but after 15 minutes they still had no
significant effect. I got rolling slowly and they cooled enough to keep my
speed under 40 mph. It was pretty scary.
Mike
11-19-2006 | 12:00 AM
#45
Guest
Posts: n/a
Re: automatic car
"Robert" <kraft.fhs@gmail.com> wrote in message
news:1163904215.591388.163320@h48g2000cwc.googlegr oups.com...
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
With disc brakes it isn't as big a problem, but I remember driving our
family '67 Chevy with 4-wheel drums down a long descent somewhere near Bonny
Doon, CA. I had the two-speed automatic in low gear (top speed about 55 mph)
and within a few minutes I had both feet braced hard on the brake pedal
continuously. I was lucky to find a flat spot where could I pull off. I
tried to let the brakes cool, but after 15 minutes they still had no
significant effect. I got rolling slowly and they cooled enough to keep my
speed under 40 mph. It was pretty scary.
Mike
news:1163904215.591388.163320@h48g2000cwc.googlegr oups.com...
> Looking at it from another standpoint (saving gas), I put my car in
> neutral down long hills and just use the brakes. Never had a problem.
>
With disc brakes it isn't as big a problem, but I remember driving our
family '67 Chevy with 4-wheel drums down a long descent somewhere near Bonny
Doon, CA. I had the two-speed automatic in low gear (top speed about 55 mph)
and within a few minutes I had both feet braced hard on the brake pedal
continuously. I was lucky to find a flat spot where could I pull off. I
tried to let the brakes cool, but after 15 minutes they still had no
significant effect. I got rolling slowly and they cooled enough to keep my
speed under 40 mph. It was pretty scary.
Mike