Howard

If you want to launch your car from a light, and I don't mean reving to 9 grand, which does more damage? Reving the car while braking and then dumping the clutch, or reving the car while feathering the cluth and then letting it out slowly as you start to move. I hope I have made this clear.

StewC625

If you're feathering at high revs, you are causing very fast clutch wear.

Dumping the clutch at high RPM does other damage - it shocks the hell out of the entire driveline - the axle "winds up" (it literally rotates in it's mounts around it's axis until the hard resistance of the bumps stops is met, and then snaps back - that causes axle hop) causing axle hop, the axle hop thrashes the hell out of the driveline, the universal joints, final drive seals, and rear end seals all get stressed, etc.

What kind of "launch" do you want? If it's a drag strip launch, then yup, 7500 RPM and dump the clutch. Beats hell out of the car, but you go fast.

For autocrossing, my one outing that I did, a 4000 RPM drop was enough.

Here's a rule - if you can smell the clutch, it was not good for the car ...

zevans

4000 revs or so seems to be the point of diminishing returns - which makes sense if you think of the torque curve on these anyway.

Don't dump it, but let it out quickly whilst increasing throttle - imagine there's a string between your feet so your right foot moves down whilst your left foot moves up. The idea is just as you have full bite you've just got to full throttle.

And go ALL the way to limiter in first - you get into 2nd much quicker and smoother that way. If you shift at 8500 in first you end up too far out of the power in 2nd. (A bit like being off-cam on a piston engine if you will.)

zevans

As an aside does the CF prop twist more or less than a steelie would?

Howard

[4000 revs or so seems to be the point of diminishing returns - which makes sense if you think of the torque curve on these anyway.

Don't dump it, but let it out quickly whilst increasing throttle - imagine there's a string between your feet so your right foot moves down whilst your left foot moves up. The idea is just as you have full bite you've just got to full throttle.

And go ALL the way to limiter in first - you get into 2nd much quicker and smoother that way. If you shift at 8500 in first you end up too far out of the power in 2nd. (A bit like being off-cam on a piston engine if you will.)]

Thanks, I believe this answers my question. I am already doing about what you are saying but need to refine it. Thanks for the tip on going all the way in first.

mtnpass

Well said, I have found that launching at 4000 rpm is a good compromise as well. Good luck Howard.

P.S. After repeated attempts at 4000rpm, may require neckbrace.....lol :D

zevans

Now try it in a Z with 350bhp and an RPS clutch :D