View Poll Results: How do you decelerate?
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How do you decelerate?
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Originally Posted by marks_lude,Apr 10 2008, 09:33 AM
dude... im gonna start this by saying... this was a huge habit of mine in my prelude, i dont do it in the S because the tranny is worth more if i **** up, and the shifting is notchy which makes it hard... so....
So in my prelude, i frequently drove, both up and down shifting... never using my clutch to shift. i would simply rev match and never had a problem doing it, and never grinded gears. i didnt care much because my friend had a lower milage tranny he said i could have at anytime if i wanted. so if your clutch is never pressed in, the plates never seperate, and there is no wear at all. the same thing happens when you rev match, except you press the clutch in anyways just in case your revmatch is off slightly.
i did this for thousands of miles and never had an issue. ill have to admit... i learned to do it on my old 88 ranger back when i was 16.. and i did grind the gears several time... but who cares about an 88 ranger.
So my point was... yes it is possible to do 0 wear rev matchin. its not easy.. because if you off my 200 rpm, or even 50 rpm.... there is still some very very very minimal wear, but there is nothing that makes it impossible to match perfectly.
So in my prelude, i frequently drove, both up and down shifting... never using my clutch to shift. i would simply rev match and never had a problem doing it, and never grinded gears. i didnt care much because my friend had a lower milage tranny he said i could have at anytime if i wanted. so if your clutch is never pressed in, the plates never seperate, and there is no wear at all. the same thing happens when you rev match, except you press the clutch in anyways just in case your revmatch is off slightly.
i did this for thousands of miles and never had an issue. ill have to admit... i learned to do it on my old 88 ranger back when i was 16.. and i did grind the gears several time... but who cares about an 88 ranger.
So my point was... yes it is possible to do 0 wear rev matchin. its not easy.. because if you off my 200 rpm, or even 50 rpm.... there is still some very very very minimal wear, but there is nothing that makes it impossible to match perfectly.
If a person shifts gears without cycling the clutch, the clutch plates will not suffer wear.
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From: Miami
i got tierd of reading, so idk if anyone else stops like this, its probably a killer for the clutch. I usually stop neutral then brake. But if I need a more immediate stop..Lets say im in 4th gear and im about to get the yellow light but I dont have enough time to pass it, I put the car in second, brake and release the clutch slowly at the same time.
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I (sometimes left foot to help get the feel for it as I'm teaching my left foot to feel the brake pedal) brake in gear (until I'm about to stop, then clutch in) and revmatch with each downshift. I also heel/toe downshift as often as possible as I'm trying to program myself to do it without thinking for auytox/track use.
Joined: Apr 2007
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From: Long Beach, MS
I've read here and elsewhere about how rev-matching on downshifts is benificial to the transmission in general and to the synchros specifically. But I can't see how this is possible.
The thing is, when the clutch is disengaged the engine and flywheel are no longer connected to any part of the transmission. So engine RPM can't have any effect on gear engagement going on inside the trannie.
The clutch is not re-engaged until shifting is complete and the newly selected gears are fully meshed.
I DO see how rev-matching will save wear and tear on the clutch disk and drive train. And I DO agree that rev matching is a good habit and absolutely necessary in high performance driving because it provides a smoother transition from neutral to engine braking, thus unsettling the car much less.
I think the idea that rev matching is less abusive to the transmission and/or synchros comes from two sources...clutchless shifting in certain racing applications (dog boxes used for rallying, true speed shifting in quarter-mile, etc). I think another source may be peoples experience with vehicles that have clutches that "drag"...ones that don't fully disengage, due to improper application, poor clutch design, improper stepping of the flywheel, warpage of the flywheel or clutch disk, etc.
Now this next is just my semi-informed opinion: I doubt using engine braking extends the life of your brake pads by an appreciable amount in an S2000. But I also doubt that engine braking significantly decreases the life of an S2000 engine and drive train, if good technique is used. But this may not be true for all applications. Take the guy who posted previously about his Camero going through brake pads a lot faster when he uses just the brakes to stop with no engine braking. There may be other applications where the wear and tear on the clutch is a lot more significant when the driver consistantly uses downshifting and engine braking. And not everybody can consistantly rev match accurately on downshifts. Like any skill, this one responds to a combination of practice and aptitude.
And to those who keep chiming in that brake pads are cheaper than a clutch I say this...
I AGREE that downshifting and using engine braking will increase clutch wear even with decent rev matching.
I AGREE that the this practice does, in fact, reduce brake wear.
I DO NOT AGREE that the tradeoff has any real world significance in an S2000. The amount of clutch wear caused by proper downshift/engine braking is minute compared to all the other factors (like launching from a stop) that wear out the clutch disk. Chances are you will trade in the car before you wear out the clutch in either case. Or if you keep the car long enough or abuse (in a good way, of course) the clutch enough you will have to replace it. But during the entire time you own the car I can't see this technique adding a single clutch replacement to your service history.
The thing is, when the clutch is disengaged the engine and flywheel are no longer connected to any part of the transmission. So engine RPM can't have any effect on gear engagement going on inside the trannie.
The clutch is not re-engaged until shifting is complete and the newly selected gears are fully meshed.
I DO see how rev-matching will save wear and tear on the clutch disk and drive train. And I DO agree that rev matching is a good habit and absolutely necessary in high performance driving because it provides a smoother transition from neutral to engine braking, thus unsettling the car much less.
I think the idea that rev matching is less abusive to the transmission and/or synchros comes from two sources...clutchless shifting in certain racing applications (dog boxes used for rallying, true speed shifting in quarter-mile, etc). I think another source may be peoples experience with vehicles that have clutches that "drag"...ones that don't fully disengage, due to improper application, poor clutch design, improper stepping of the flywheel, warpage of the flywheel or clutch disk, etc.
Now this next is just my semi-informed opinion: I doubt using engine braking extends the life of your brake pads by an appreciable amount in an S2000. But I also doubt that engine braking significantly decreases the life of an S2000 engine and drive train, if good technique is used. But this may not be true for all applications. Take the guy who posted previously about his Camero going through brake pads a lot faster when he uses just the brakes to stop with no engine braking. There may be other applications where the wear and tear on the clutch is a lot more significant when the driver consistantly uses downshifting and engine braking. And not everybody can consistantly rev match accurately on downshifts. Like any skill, this one responds to a combination of practice and aptitude.
And to those who keep chiming in that brake pads are cheaper than a clutch I say this...
I AGREE that downshifting and using engine braking will increase clutch wear even with decent rev matching.
I AGREE that the this practice does, in fact, reduce brake wear.
I DO NOT AGREE that the tradeoff has any real world significance in an S2000. The amount of clutch wear caused by proper downshift/engine braking is minute compared to all the other factors (like launching from a stop) that wear out the clutch disk. Chances are you will trade in the car before you wear out the clutch in either case. Or if you keep the car long enough or abuse (in a good way, of course) the clutch enough you will have to replace it. But during the entire time you own the car I can't see this technique adding a single clutch replacement to your service history.
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From: Dry Branch
At last! A post that leads to some intelligent discussion. 
I was seriously about to give up on this thread entirely Ruprecht, but then you had to turn the craziness back into a serious conversation, so I'll jump back in here for a bit, even if it's just to talk to you.
[QUOTE=Ruprecht,Apr 10 2008, 12:15 PM]The more times you use something, be it a clutch, a pencil, brakes, etc.
I was seriously about to give up on this thread entirely Ruprecht, but then you had to turn the craziness back into a serious conversation, so I'll jump back in here for a bit, even if it's just to talk to you.
[QUOTE=Ruprecht,Apr 10 2008, 12:15 PM]The more times you use something, be it a clutch, a pencil, brakes, etc.
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From: Dry Branch
Originally Posted by tof,Apr 10 2008, 01:55 PM
I've read here and elsewhere about how rev-matching on downshifts is benificial to the transmission in general and to the synchros specifically. But I can't see how this is possible.
Rev matching doens't do a thing to help the synchros. Anyone who tells you it does is talking smack. They are running off at the mouth without actually having a clue, and can rightly be put in the general classification of "moron." They're not morons becaues they fail to understand the difference between a rev match and a double clutch (we all had to learn this at one time or another), but they are morons for being so stupid as to shoot off their mouth when they haven't got a clue WTF they're talking about.You are wise to question the advice you get from morons.
AND, you are right in thinking that rev matching does absolutely nothing to save the synchros. Never take the word of people who don't have a sensible explination (using either physics or common sense). If it sounds wrong, it probably is wrong.
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From: Dry Branch
Originally Posted by CrankDatVtec,Apr 10 2008, 01:24 PM
i got tierd of reading, so idk if anyone else stops like this, its probably a killer for the clutch. I usually stop neutral then brake. But if I need a more immediate stop..Lets say im in 4th gear and im about to get the yellow light but I dont have enough time to pass it, I put the car in second, brake and release the clutch slowly at the same time.
It's pretty obvious that you got tired of reading before you learned anything, but don't feel bad. You're hardly the first.
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From: Dry Branch
Originally Posted by tof,Apr 10 2008, 01:55 PM
But during the entire time you own the car I can't see this technique adding a single clutch replacement to your service history.
I downshift habitually, for lots of reasons, many if not most of which I have explained elsewhere in this thread. The morons who STILL want to insist that this is causing excessive clutch wear need to explain why my clutches typically last for well over 100,000 miles. WELL OVER. Anyone who says it isn't so, after all this, is just a dumbass.
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From: Dry Branch
Originally Posted by EBinVA,Apr 10 2008, 01:43 PM
I (sometimes left foot to help get the feel for it as I'm teaching my left foot to feel the brake pedal) brake in gear (until I'm about to stop, then clutch in) and revmatch with each downshift. I also heel/toe downshift as often as possible as I'm trying to program myself to do it without thinking for auytox/track use.
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Ok...So, I'm a little confused as to how double clutching saves the synchros. I mean, I understand the basics, just not the complete operation of the transmission...
When I downshift from 6th to 3rd, the synchros engage the gear ring for 3rd gear to turn them up to match the speed of the output shaft, is this correct?
I've been told that I should pass through all the gates 6-5-4-3 before releasing the clutch to reduce wear on the 3rd gear synchro. That doesn't really make sense though. If the car is traveling at 45mph, the 3rd gear synchros better be able to spin the 3rd gear ring up to the appropriate speed, right? So why do I need to engage all the other synchros on the way to 3rd?
Does what I'm asking make sense?
When I downshift from 6th to 3rd, the synchros engage the gear ring for 3rd gear to turn them up to match the speed of the output shaft, is this correct?
I've been told that I should pass through all the gates 6-5-4-3 before releasing the clutch to reduce wear on the 3rd gear synchro. That doesn't really make sense though. If the car is traveling at 45mph, the 3rd gear synchros better be able to spin the 3rd gear ring up to the appropriate speed, right? So why do I need to engage all the other synchros on the way to 3rd?
Does what I'm asking make sense?