I have been having troubles with my clutch slipping on the dyno. I had a SPEC Stage III in the car (the old style-all carbon) last year. The clutch had ~15,000 miles on it and worked great, or so I thought at 350 rwhp. It was EXTREMELY grabby from a stop, and felt good all the way to redline. Well, I added 6 psi of boost to it, and when trying to tune the car, it would just rev really quickly and not get any power to the ground (most it has made with the blower is 350 to the tires). It is definitely a clutch issue of some sort. Ever since the car was stock the clutch wouldn't engage till all the way to the top of the pedal travel. So, I thought that the old SPEC had just gotten too warn out.

So I ordered a new stage III (the new style), along with a SPEC steel flywheel. The old one I took out had some wear, but didn't really have any hot spots on it like I expected, but I replaced it anyway. The new one is MUCH more streetabe, and I thought it was better than the last. It still engaged all the way at the top, but I didn't think twice about it since the car always has.

Got about 400 miles of easy, in-town break-in miles on it, and hit the dyno again....SAME THING! Exactly.

So we thought it just wasn't releasing all the way, so I shimmed the slave cylinder out (towards the back of the car) about .400". This made the pedal engage a little lower (not much), but it is still slipping.

Has anyone had this problem before??? I'm only expecting the car to make about 450 to the tire, so it's not like it's a really high powered set-up.

Please help!

 

Did you turn the flywheel?

If you did(good) but did you shim the back of it with the same measurement?

If not(that could be why, the new clutch should work better with a new clean surface

 

The old clutch had a stock turned flywheel with no shims. The new clutch as a brand new SPEC steel flywheel.

 

anybody?

 

Just to fill you guys in on what I found out......

Had the car back on the dyno today, to test my clutch to try and nail down what was happening. Pulled it on, then jacked it up and pulled the slave cylinder off. Started the car in gear, and ran it up into 4th without using the clutch pedal. Well, it slipped again!

At this point we explored a different thought-maybe, just maybe I'm spinning the tires on the rollers. I do have some 4 year old Bridgestone Potenza RE910's on the stock salad shooters, so I guess it COULD be?? Well, we pop the hatch and 2 of us lean over and lay in the back-guess what? It ran up like it was supposed to!!!

All this time it was spinning the tires on the dyno, and I thought it was the clutch.

They had a set of ET Streets there in the shop (on 16" SS wheels), so I threw them on to continue tuning the car. Still have a little bug that needs worked out, but I'm happy with the results!

462 hp
401 tq.

This is on 6 psi.

I'm all 's now!