rev matching - over/under - which is worse?

[BlahBlahYouToo]

i always rev match when shifting but sometimes i won't get it right. i'll over shoot or under shoot it by a couple hundred rpm, and it will jerk the car.

is one worse than the other, or are they both equally bad?

 

[jhu]

you should let up on the clutch pedal a little bit slower if a few 100 rpm is jerking the car.

 

[The Boston Dangler]

only a couple hundred rpm? i would think being a little smoother with the clutch would fix that.

 

[Arkaign]

A couple hundred RPM jerks the car? What are you driving? I would imagine that undershooting is a little worse, but that both aren't too bad. It sounds like you're letting the clutch out too fast.

There is one thing I do know :

The clutch is pretty much the cheapest thing in your drivetrain as far as serious parts. Sounds like you just need to let the clutch slip more so that the flywheel can sync up and you can ease into gears more smoothly. Hopefully I'm understanding/communicating that correctly. ZV will have the concrete story. But I do know that replacing a clutch is *fairly* cheap, and if you only have to do it every 100k-150k miles, it's a lot cheaper than rebuilding a tranny for broken gears/synchros, etc.

 

[JDub02]

Originally posted by: Arkaign
A couple hundred RPM jerks the car? What are you driving? I would imagine that undershooting is a little worse, but that both aren't too bad. It sounds like you're letting the clutch out too fast.

There is one thing I do know :

The clutch is pretty much the cheapest thing in your drivetrain as far as serious parts. Sounds like you just need to let the clutch slip more so that the flywheel can sync up and you can ease into gears more smoothly. Hopefully I'm understanding/communicating that correctly. ZV will have the concrete story. But I do know that replacing a clutch is *fairly* cheap, and if you only have to do it every 100k-150k miles, it's a lot cheaper than rebuilding a tranny for broken gears/synchros, etc.

The clutch is cheap. The job can run well over a grand. Still cheaper than a new transmission.

 

[Howard]

This thread sure makes me feel better about my technique. Engaging the clutch when the revs are off by as little as 100RPM is definitely noticeable in my car.

 

[BlahBlahYouToo]

ok, maybe i underestimated.
i say the worst case is when i bang the shifter in between gates. by the time i get it in gear, the RPMs have dropped to idle so i'll have to bring it to 2-2.5k. sometimes i undershoot and only blip it to about 1500.

 

[spidey07]

Just keep practicing and let the clutch do it's job. After a while you won't even have to think about it. You could say both are equally as "bad", but that's what the clutch is for.

Also if your revs are dropping to idle, get quicker at shifting...they shouldn't drop a whole bunch.

 

[Zenmervolt]

If you're sidestepping the clutch, that's bad, hard on everything from the clutch center to the differential, but unlikely to be catastrophic. If you're just talking about a little bit of unsettling, then that for all practical purposes that's nothing to worry about. A good upshift will always be a little firm. Downshifts you want to modulate a little more, especially if it's mid-corner, but I doubt you're pushing it hard enough to worry about that.

As far as over/under, I don't see a reason why it would make much difference overall. If you're still applying power and it's over, I can see that wearing the clutch slightly more (since the engine is giving even more than usual resistance to changing RPM due to the extra throttle you're applying), but I doubt that's the case.

Honestly, you're probably over-thinking it. I always shift best if I'm just not giving it conscious thought.

ZV

 

[alkemyst]

just practice more. Don't focus on the over or under...just do it right.

 

[JulesMaximus]

Originally posted by: Howard
This thread sure makes me feel better about my technique. Engaging the clutch when the revs are off by as little as 100RPM is definitely noticeable in my car.

Try it on a motorcycle. Easing it out smoothly is definitely key...especially on a machine that will rev to 11,000rpms in about 1.5 seconds while propelling you to over 40mph in that time.