AP2 David

rev match!!! ftw!!

smurf2k

+ on Nate and Apollo
- on mikegarrison

Apollo

Let's clarify this once again, rev-matching (by the generally accepted definition) does nothing. It's the exact same thing as if you hadn't rev-matched to begin with. You are doing the exact same thing as those Woodwork points out in terms of load on the synchros.

Double de-clutching is the correct term and method for skip downshifts. It is the method that lessens the work done by the synchros. Read previous posts to understand the differences in terms of mechanics.

It may sound like semantics, but they are completely different techniques with one lessening the synchro load (double ) and the other doing absolutely nothing for the synchros (rev-match). While we all may have our theories on it, this jumbling of terms will only confuse people searching for true technical answers.

shotgunjimmy

one thing id like to ad is what rev-matching is good for. rev-matching when downsifting uses the accelerator to speed the engine up to the rpm for the desired gear/speed. not rev-matching uses the friction of the clutch to speed the engine up, which will cause undo wear on the clutch.


thanks

james

mikegarrison

Wrong. Try downshifting in the middle of a corner without blipping the throttle, and find yourself spinning. Then try it while blipping the the throttle, and find that it works.

The rev matching avoids the engine-driveline speed mismatch and the resulting engine-braking effect.

It may do nothing for the synchros, but it does a lot for the dynamics of the car as a whole.

SIIK2NR

Wrong......

smurf2k

i think he may have thought it correctly but expressed it wrong.

correct: rev-matching is independent of synchronizers. does not ease/smoothen the shift (driveline vs tranny)

its purpose is to ease/smoothen the engagement of tranny and motor. (to reduce shock and maintain dynamic balance in corner, like you said)

Apollo

I was not referring to vehicle dynamics. In my post, I am referring purely to the load on the synchros. The OP is posting about skipping gears on downshifts. Skipping gears is something not recommended by Woodwork based on the synchros not being designed to handle that the larger load. I'm trying to clarify as to the distinction of what helps the synchros and what does absolutely nothing for them.

I agree with you on the dynamics, but my point of contention is it does absolutely nothing to help the issue of loads on synchros from skipping gears. Hence why it is not a suitable method for skipping gears. And why I wanted to differentiate rev-matching from double de-clutching. I'm just evidently not clear enough in my wording.

Quoting myself from post one as to what rev-matching does:
Rev-matching REQUIRES rowing the gears as the synchros were not designed for the heavy hits of taking the giant difference in rotation speeds from skipping gear. Rev-matching does nothing for the synchros; all it does is match engine to transmission for a smooth clutch out.
Rev-matching is not the same as a double de-clutch. The "feel" is the same when you clutch out, but the way the transmission internals move are different.
Post Two referring to the differentiation between what helps and/or does nothing for the synchronizers:
[I] Let's clarify this once again, rev-matching (by the generally accepted definition) does nothing. It's the exact same thing as if you hadn't rev-matched to begin with. You are doing the exact same thing as those Woodwork points out in terms of load on the synchros.

chuhsi

i never skip gears and always rev-match.

Apollo

How does rev-matching help my synchronizers? Please explain to me as I don't see it, unless you're referring to double de-clutching as "rev-matching" in your book.