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Puck type clutch disk?

I'm barely a 1000 miles into my EFI conversion and my new Centerforce clutch has given up at 400ft-lb torque at the wheels. I'm hoping I can get away with just changing the clutch disk. Anyone have recommendations for a puck type disk. How about spring centered or solid? I've driven a solid disk race car but never a street car with one. I heard one recommendation to soak the new disk with WD40 and then bake it to season it. They said this would cut down on the clutch chatter from using a racing disk on the street.
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Old 07-14-2007, 06:47 AM
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A fellow 930 owner tried the puck style for street and hated the chatter. To stop the chatter, he slipped the clutch on starts and ended up burning it up. I have a kevlar compound, solid, center spring disk with a stage II KEP pressure plate and stock flywheel. Besides being a bit heavy, its as smooth as any of them controlling +520RWHP. Good luck.
Old 07-14-2007, 07:01 AM
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Quote:
Originally posted by DonE
A fellow 930 owner tried the puck style for street and hated the chatter. To stop the chatter, he slipped the clutch on starts and ended up burning it up. I have a kevlar compound, solid, center spring disk with a stage II KEP pressure plate and stock flywheel. Besides being a bit heavy, its as smooth as any of them controlling +520RWHP. Good luck.
DonE, did you get the kevlar plate from KEP as well?
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Old 07-14-2007, 07:17 AM
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i have a kep and a 6 puck clutch(sorry i dont know what brand it is).i like how graby it is.it sometimes does chatter abit.i would think it depends on the person if you like that or not(i like it).and i would make sure it has the spring center.think it would be hard on the tranny without it.
Old 07-14-2007, 09:41 AM
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oh and this is probably obvious but make sure you have the correct free play in your clutch arm
Old 07-14-2007, 02:54 PM
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Quote:
Originally posted by spuggy
DonE, did you get the kevlar plate from KEP as well?
No, but they might be able to get one for it. I think I got it from Turbo Performance in MD - good guys.
Old 07-14-2007, 05:10 PM
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David,

Had you considered trying a stock 3.0 disk? They can take a surprising amount of torque with the right pressure plate. I had one with a Sachs PP that easily withstood 423 ft-lb at the rear wheels, and I've heard of them working on engines that have well over 500 ft-lb at the rear wheels. I have a SPEC disk ("ferramic" all-metal, spring centered, full circumference) coupled with a beefed up Sachs sporting clutch. It's crisp and capable, takes modest pedal effort, and relatively inexpensive, but it's heavy and there is some chatter when starting. It's supposedly bulletproof and good for 650 ft-lb (at the crank). I sort of wish I'd tried the stock disk, and I still may, just to increase the friendliness factor, especially given that I have an inordinately tall first gear. But it's a pain to experiment with different clutches, so I'm okay living with a little chatter for now.

Also, not knowing more, I wouldn't necessarily dismiss your problem as a disk-only issue. Any chance the pressure plate was not up to snuff? What were the symptoms of your clutch failure? It might be good to send the whole thing to Kennedy, Centerforce, SPEC, or some other clutch specialist for an evaluation.
Old 07-20-2007, 12:00 PM
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One more thing; I think most puck-type clutches are almost unmanageably hard to use on the street. I'd be interested to know if you find one where the claim is otherwise. Seems to me you should have plenty of more streetable options.

Last edited by Rob 930; 07-20-2007 at 12:13 PM..
Old 07-20-2007, 12:07 PM
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OK, I have to come clean... I had the clutch adjusted too tight

It seems to be holding pretty good now, but with the never ending rain we've had, I haven't had a good hard drive since last week.

There's a PCA dyno day next weekend, so hopefully I can get out there and get a good pull without the clutch slipping.
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Old 07-20-2007, 04:05 PM
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my stock one made all of 2 months now it slips whenever the boost kicks in. I still dont have even everything dialed in yet. I ordered a spec stage 3 with a 6 puck plate from lindsey racing . I'll see how it goes. the reason i chose that was if it's too stiff i can stick a hybrid disc in and if I go the dark side with efi it will still be strong enough to take it. they told me the stage 4 is chattery and rough but the 3 is supposed to be ok I'll let every body know in a couple weeks.
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Old 07-25-2007, 01:22 AM
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I'm sending my clutch out to Fort Wayne Clutch for the Kevlar upgrade .

Price isn't too bad either .

Although our shop has a flywheel grinder I'm also sending the flywheel to them for machining . They're a full service shop .

SxS
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Old 07-26-2007, 08:31 PM
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Hello!

You are an engineer, right?

Puck-type disc will usually not hold for more torque. Actually, it's pucks usually have less mu, less friction than organic stuff on ordinary clutch. Only difference is that they will hold for more heat w/o going up in smoke (chewing away your flywheel in the progress).

W/o words, you could remove organic material from your ordinary disc and install pucks. The less pucks you have the greater pressure per square inch you get, but the less surface also.

With other words, only thing pucs do is to raise contact pressure per square inch, but total friction stays the same due to less surface.

Only reliable way of increasing the torque specs is fitting stronger pressure plate. In case you don't do track-only, I recomend keeping the stockish disc and increasing the pressure plate force. It will still give somewhat normal slipping characteristics opposed to pucked disc and hold for torque.

Then there is a issue of aftermaket puck-discs usually not having dampening springs in the middle. Tose springs are there to even out power-pulses going into the gearbox. Not having them increases wear and tear as inpuut shaft will be banged by micro-bursts.

So all in all, stay clear of undamped pucks unless you emptied other solutions: stronger pressure plate is the first to try.
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Old 07-31-2007, 02:00 AM
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