Hi Everyone! I really want to know if rev-matching when downshifting can inadvertently bend valves such as if you let the clutch out too fast and feel a jolt because of a mismatch in engine and transmission speed. I don't actually rev-match at high rpms but I have always been curious if it can affect components in the valvetrain. If not, can rev-matching wear down the differential? I apologize ahead of time if this question sounds confusing or dumb. Thanks guys!

 

Rev match matches the speed of your car and the speed of your engine. Its to make a smoother transition. Unless you rev match like shit no

 

In a perfect downshift you should be able to 'drop the clutch'. As in, your engine speed is at the right speed to match the road speed of the gear. Sure, you can do damage to your diff if you dont give enough gas since you can lock up your rears.

 

If you feel a "jolt", then you're not rev-matching. You're rev-unmatching. Proper rev-matching makes for a smooth transitions into the next gear and does absolutely no harm to any of the drivetrain components.

 

this

 

Your valves have no idea why they are being sped up, or slowed down. They won't know weather you are pumping the throttle in neutral, to impress yourself, or passers by, or are going back a gear or 2, into a hairpin.

Asking them to speed up a bit by the odd mismatched gear change, or blipping in neutral will have no detrimental effect on them.

They won't even be able to tell your mechanic of your poor driving, as you won't have caused a problem.

Your diff & clutch, on the other hand won't like it too much. Minor miss matching they will take in their stride. If however, like acquaintance of mine, you do fast take-offs by moving your clutch foot sideways, off the clutch pedal, at high revs, they will soon be telling your mechanic of your driving habits, as he replaces them.

 

Yah, the reasons for rev-matching on a downshift are to prevent beating the crap out of drivetrain components like the clutch, u-joints, and diff. And so that you make smooth transitions while braking for a corner when the suspension and tires are already loaded near their traction limits. Bad things happen with sudden herky-jerky inputs under these conditions. Done properly, gear changes are smooth as glass. And you're only blipping engine speed less than 1,000 rpm for a one gear drop in most cars.

On the other hand, if you are a jackass running at redline in 5th trying to jam a skipshift down to 3rd.........some engines can't take the overspeed condition and yes, you can break shiit in the engine. You need to be aware of your rpm overhead when downshifting.

 

x2

 

In the case track driving (or even street driving), an S2000 isn't like "most" cars. If you're approaching a corner, you've likely backed off on the gas already and the engine rpm is decreasing rapidly (track). You wait till it's safe to downshift. Safe, meaning the rpm will be low enough so that after the downshift, your rpm won't go beyond redline. In an AP1, for example, you could be blipping the throttle as much as 2500 rpm or more (eg. 3rd to 2nd shift could take your rpm from 6500 rpm to 9000 rpm). If you're just goofing around on the street, you could be blipping thousands of rpm to achieve a proper rev-match. (As we've seen more often than not, "goofs" or "jackasses" rarely really know how to drive on the street and they tend to do things that are unconventional and dangerous for both the car and humans for the sake of drawing attention to themselves.)

As an after-thought, I'm starting to think the Topic Starter may not actually understand what "rev-matching" is because when the "revs are matched" on a shift (and it doesn't matter if it's an UP-shift or a DOWN-shift), there will never be any "jolt". If he's "jolting", he's just shifting "willy nilly". There is no clutch/throttle/shift synchronization going on.

 

i rev match anytime i downshift...its just something ive embedded in me so most of the time its just second nature...never once has the car "jolted" on me...ever