tconn

My stock clutch is no match for the Vitesse stage 2 kit. It's starting to slip in 1st
and 2nd gears when I really get on it.
I've had a local Porsche mech tell me a new stock would be fine and I've had
Paragon tell me that their sport clutch (cup clutch I think) would be fine.
The Spec clutch is a good price but I don't really want a clutch that chatters.
Will the Cup clutch handle 400rwhp?

Thanks

special tool

NO STOCK CLUTH WILL HANDLE THIS POWER AT MAXIMUM BOOST. Anyone who tells you different, has never driven a fast 951. It takes a special clutch to handle the torque rise on your car.
You can get away with a stock pressure plate if you use a copper/ceramic 6 puc (with springs if you like) disk. This compound has a much higher coefficient of friction and is much better resistant to slipping and oil contamination.

Anyone who mentions kevlar for a 951 streetcar, is an idiot.

David Floyd

I think Cup is what John has in his race car.

I would go with a KEP PP and cup or 930 disc.

"jwl" is using the KEP and 930 disc, says no chatter.

You have been in my car and know the 6 puck does chatter.

The stock disc and KEP is rated at something like 600 ft lbs

special tool

David - I suggested to Ted that he try only the copper disk and stock PP on his stage 2, and it seems to be holding well at 24 psi. Even though I have the KEP and copper disk, I think the copper disk will be enough for a guy on a budget, now that I have seen the results from both. If I was doing it again, I might just use the disk alone.

SoloRacer

Tool: Why would recommending a Kevlar clutch make one an idiot? I got a Kevlar clutch from Markus at Blaszak Precision and it's holding up well to my Vitesse Stage 3. It cost the same or even less than the stock clutch and isn't hard to drive at all. I agree with the Kennedy pressure plate. Kennedy Engineering makes some nice stuff and Hobart Kennedy himself is a stand up guy.

tconn

Thanks for the info. I knew the mech was full of it but was not sure if the cup
car kit had a beefier pressure plate or not.
David has your clutch smoothed out any ?
Who has the best prices on the KEP pressure plates?

Thanks

special tool

Solo - your KEP is doing ALL the work. If you used a stock PP, it would slip at 350 RWHP, maybe less. On the other hand, I have seen that the copper can stand alone on a high HP 951 - like yours.

SoloRacer

Tool: I'm using the stock pressure plate. I have bought stuff from Kennedy Engineering for my project 914 and know Rage uses a Kennedy pressure plate on his high H.P. 951. My clutch hasn't slipped due to the kevlar disc that I know of so far. A friend of mine is using a Kevlar disk on a 600 hp RX7 and it doesn't slip. What are you basing your assumptions on?

tconn

Will a stock PP and copper disk chatter?

special tool

Yes - even with springs.

SoloRacer

A friend of mine ran a 6 puck unsprung copper disk on his RX7 and after 1.5 years of service it ate away enough of his flywheel and pressure plate that they had to be replaced. Are you guys seeing any wear of your pressure plates and flywheels with the copper disk?

special tool

Solo - kevlar and the stock disk??? Oh boy. Have you dynoed your car?
The stock PP can hold enough to make the slippage very linear and almost unnoticeable - even on the dyno, it was hard for me to diagnose as clutch slippage. I tried a few other things first.
You are going to have serious trouble with that setup. If you hit a wall at around 375 on the dyno - look at the clutch. Experience, not bull****.

And ask Marcus for his 951 dyno sheets with that clutch setup.

jturbo

tconn,

I have a Center Force Dual Friction Clutch in my 951. Not sure what the pressure plate was made of, but it is very smooth and shifts great. The only complaint that I have is that I SOMETIMES? get a little vibration when I engage the clutch when starting from a dead stop. This could be the motor mounts need replacing, but I'm not sure. My car has 400HP at the flywheel and I have not had any problems with the clutch not being able to handle the power.

SoloRacer

Tool: I guess I will find out when I go to the dyno later this month. If I have problems with this set up I'm definitely going to be talking to Kennedy Engineering for their full kit. So for Marcus has treated me very good and hasn't given me any bad advice. I'll keep running what I got and see how it holds up.

WesM951

Ok, side question but still peratins.

The cup clutch kit, is that a stock PP?