HEAT'N'COOL

Hey guys and gals. I wanted to get some clutch advice... Yesterday while taking a drive i was getting on the freeway and got into full boost and noticed my clutch slipping. Grabs when not in boost then the GT35R kicks in and slippage... I was wondering what you all thought would be the best solution for my setup.. I will be doing some DE/Auto X events and of course some spirited driving! Car currently has 501whp and 488wtq. I have read a lot about KEP clutches on here.. sounds like a great product.. Yes i searched.. and read...

Please give me recommendations of what you think is the best and WHY?

Thanks in advance,
Chris

speednme

Chris do you have an afr gauge? The reason I ask is that what sometimes seems like clutch slippage is actually detention due to leaning out...

HEAT'N'COOL

I do not. It is actually running rich right. I throw flames all over the place when off gas. I am familiar with running lean. This is definitely the clutch! I am however going to run it easy until I get it re tuned by Chris German because it was running rich.

MUSSBERGER

Not sure of the reason for the 993 clutch but it is not even close to being correct for the horsepower that car is producing. The right KEP is certainly an answer but going too far with clamping force can make drivability a bit of a pain. I think the key to any high performance clutch is finding the right balance of grab and ease of engagement.

HEAT'N'COOL

I agree with you.... I am either going to go with the stage 1 or 2. Not going to go with the Racing clutch.. I am leaning towards the stage 2... who knows i may want to re tune for more power in the future..

Mark Houghton

Similar thing happened to me many moons ago when I started adding bolt on power. The clutch definitely slipped when hitting the torque curve on boost, not to be confused with lean detonation. I went with KEP stage 1 and it is more than sufficient for street use. No issues whatsoever.

Menmojo

I installed a KEP stage 2 last summer.
So far it's great. The pedal is firm and I do get some chatter starting in first gear once the car is warmed up. It's very manageable and not a big deal.
The stage 1 is rated for 550 ft lbs of torque, stage 2 650 ft lbs.
My car has a lot of torque.....on the Dyno it peaked at 655 ft lbs.
This is why I chose the stage 2.
Now that I'm running less boost my peak is probably closer to 600 ft lbs.
I haven't put enough miles/time to give it a rave review but so far I'm very happy with it.

HEAT'N'COOL

Menmojo,

Thanks for the feedback. I am going with a stage 2. I have room with my build if I want more power so just in case i get the itch the clutch wont fail like it is starting to do. Excited to get it installed so i can take the beast back out for spirited drives !! Right now I cant put the car in full boost....

Mondragon

Hi I have a Spec Clutch Stage 3+, it is a pig to get off the line and it is supposed to be the "Flag Ship" product. when i received the clutch it is clearly a rebadged Sachs clutch plate with a Spec disc. not impressed.

it chatters so much off the line that i will be replacing it wit a KEP as soon as i can. i have given it the break-in period that they recommend and its not improving. i would not buy a Spec clutch again...

When you are on the move it behaves like a normal clutch. the grip is fine as im running 525hp at the wheels. taking off on a slope = tyre smoke. stop start traffic is a nightmare.

dont buy one....

HEAT'N'COOL

Thanks Mondragon! I am getting a KEP stage two installed this Wednesday at Chris Germans.! I have read great things about KEP and will let you know what I experience. While in there I may get a few other things done to the car... Cheers

HEAT'N'COOL

So my car went into Chris German's Garage for a new clutch... went with The KEP stage 2...

Then I decided while it is out i would reinforce the rear strut tops with Elephant Racing Tops because the previous owner never did when he put in the RSR coilovers... and put 750lb springs to help with the squat...

Then I decided while the Transmission is out I might as well get the 2nd and 3rd gear syncros addressed and new 3rd and 4th gears... thanks Speednme !! pretty much have the same setup you did with you 915 on those gears...

Then i decided well while it is there i will get the rear deck re covered with new leather.. shrinkage over the years....

Then I decided to get the windshield replaced because the original was quite pitted...

And... I got 993 Aero Mirrors, painted and having them wired...

Well then i decided to get my Fiske's powder coated satin black...

Gosh dang I love this slippery slope!!! I CAN'T WAIT to get my beast back.

Merry Christmas to me!!

speednme

May I suggest adding Rear Monoball Cartridges and 935 Spring Plates(really makes a difference)...that will keep your vehicle from shaking that **** during acceleration. One note is I would change out those 750# for either 650 or 550 for street driving. You can either purchase from Elephant Racing or Rebel Racing.

HEAT'N'COOL

Thanks for your input. I researched both those products and think they would be a great addition for what I am going for. For the springs, I had 550# on before and boy the rear end would squat when hard on the gas. I have sent Chris Powell an email about the ride quality on the street. Thanks for bringing that up!