TGiuliante

Hey guys My clutch is slipping in my C6 corvette race car. It is a road race car. it is an LS2 motor that make approx 500-525 at wheels. Will live in 5000-6000 rpm range I currently have a 7.25'" quartermaser triple disc clutch. Clutch is slipping. I am contemplating replacing disks in clutch BUT if I go to a different clutch I will want a normal clutch with better manners. Not an on off switch. I understand the benefits of a race application but am thinking about a easier mannerism clutch with an aluminum flywheel.

What would you recommend for this application?

Thanks
Tom

RX-Ben

New discs.

J.R.

Tom,

I would look at switching over from metallic triple disc setup, which I believe uses an approx. .105 disc to a dual disc quartermaster setup using rally discs, which uses an approx. .250 disc. I think when you add up total measurement that the 3 disc metallic and the dual disc rally are the same measurement. The rally disc will give you a smoother release and longevity.

Call Quartermaster to verify above.

I think Danny Popp is using this setup on his C5.



J.R.

sperkins

The SPEC all aluminum option worked well for me for nearly 3 years. I have 2 for sale if you're interested.
One is a stage 1 and the other a stage 3. Both include alum pressure plate and alum flywheel.

crimlwC6

Stage 3 Spec w/ aluminum flywheel has worked for last 2 years on 350 hp C5 race car.

redtopz

+1. What JR said also sounds really good and I might look into that. I'm surprised this clutch is slipping unless a) you have a LOT of miles on it, b) you slipped it too much around the paddock or in/out of trailer etc. and it's prematurely worn down the discs or c) something was out of tolerance in the installation and the TO bearing is not fully releasing.

I agree this clutch is a pita in 1st gear around the paddock, but it is awesome on the track and the on/off feature is what makes it last so long and prevent slipping.

waddisme

Spec 3+ here for me for past 6 years with 500rwhp C5Z. About at the end of my second one now. Tolerable on the street as I do dd it. Wife doesn't like it as it is too hard and stiff for her.

JerryTX

How many race weekends on the clutch? Mine has 10+ race weekends and is out of the car because I blew the engine. All the discs measure between .101-.103, new is .105, worn is.095. I abuse the heck out of it and love it on track but for sure it sucks getting on the trailer or in the pits.. Wish I had better than 3.42 rear gears!

I did have to take the drivetrain apart for a slipping clutch on the second weekend after install. I had a shop install items probably done right. Regardless of install or wearing in, the throw out bearing sleeve was riding on the clutch fingers so I had to measure the proper gap and as it turns out machine a bit off the sleeve. When done it was dead nuts .200 clearance (.180-.220 is spec, I was at .185). While ..185 should have still been fine it was not in my case. I also insulated the headers as well as insulated the slave bleed and feed line to master cylinder. Between excess heat causing a crap pedal, and the fine tuning of the free play, the clutch issues were solved. This was without replacing discs, and even after some horrible clutch burn "incense".. New discs are about $525 to your door, factor that in when you consider swapping to an all new clutch.

RX-Ben

Usually you machine a bit off the legs on the TOB. My understanding is that proper TOB to pressure plate clearance is .140-.180". I think I am on the upper end of that and pedal position is perfect. A bit will need to come off the legs, and a little more so if you are using a thicker SFI flywheel.

JerryTX

I'm going off memory on my numbers I may be off. I talked with Danny Popp when it happened and went through the numbers and we agreed maching the sleeve about .015 was not a bad idea. Never heard of machining the legs but I'm sure that could work too! Learn something every day!

JDIllon

Just installed a RPS BC2 carbon with the aluminum flywheel. Love it!! Car runs great with it and it is streeable for loading the car. 24#s complete, I have several friends running it with 625+ for road course stuff. They have had it for 2 years and no problems. I have only run about 6 track days. You can call me if you have any questions. 772 335 8318 Jim Dillon

RX-Ben

That RPS is a great compromise clutch. 100% streetable and pretty light for having a flywheel. Ideal if you tug a tire trailer.

RX-Ben

Mantic 7000 and 9000 are excellent as well.

redvetracr

Quartermaster pro series 5.5" you should be able to take your (cleaned) QMI clutch parts to a QMI dealer and get the discs, floaters and cover measured and tested. heat and slipping them is what kills a multi plate mini clutch.

msracing

i am running a triple disc 7,25 and its working great ,, c6 ls2 holinger sequential 6sp

i would replace the disc and plates it will be fine and fast

NemesisC5

Had a Spec 2+ w/aluminum pressure plate and flywheel on my 02 C5z (397 rwhp) with a Mcleod adjustable master and was flawless on track and street. High rpm shifts no problem, around town light pedal pressure no chatter,,,friendly as stock.

SouthernSon

Same here, with very similar numbers. I went to the Qmaster but may go back to the spec 2+ later. I did keep it along with my tick M/C which is needed with the spec.

Chevy Nick

My wife likes it hard and stiff

NemesisC5

The clutch came with the car that I purchased used and the car "crept" in 1st gear with pedal depressed. I speculate not being shimmed properly which also caused resistance during high rpm shifts. Added the adjustable MC and all issues cleared and the system worked to perfection. The entire assembly of Spec 2+ with the aluminum PP and FW weighed 36 lbs. They now offer a smaller diameter 10.5" version of the Spec 2 (+) and Spec 3 (+) with aluminum PP and FW that reduces weight and inertia but sacrifices holding power. For application of 400-425 rwhp I think the 10.5" 2+ would be a good value of light weight, low cost and more holding power than stock LS6 / LS2 clutches.

Painrace

I hope you are not driving the car on a trailer. It kills the clutch with no low end torque!

Jim