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Old 04-16-2007, 07:44 PM   #1
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First post, be kind…

From what I have read people have differing experiences with a stock clutch and a greddy setup… I just want to clear up a few things in my mind.
According to Braineacks faq (great info) the stock clutch slips at 6psi… I think the clutch slips because it can’t hold the torque? (Correct me if a am wrong) and I know from the dyno graphs that toque increases with rpm.. So is it slipping at redline, or at 4000rpm? Or at both? I have never experienced a slipping clutch and I am a little confused, 1) does it only slip when you are letting the clutch out, say when your in first at 3000rpm, or 2) does it slip as you are driving, thus causing a loss of power?
I want to run my greddy at 5psi to start, it has a few mods and will be able to handle closer to 8, but I can’t afford to replace my clutch until the end of summer… So should I hold of on installing the kit until the end of summer and do the clutch at the same time, or install it now run it at 5psi and go easy on it.. ie no hard launches, keep revs under 6500rpm, and no dumping the clutch.

Also I do have the money to replace the clutch, and motor and anything else that might go wrong with the car, but I am budgeting myself for a bi-monthly budget (so I don’t go crazy), because of the greddy kit purchase my next allowance of money for the car wont come until the end of the summer. The car is also a daily driver, so messing it up would be back for getting to work. I live in Canada so a clutch job with parts will run about 800$, and no I don’t think I could do it myself yet.

Any input would be great, oh and this forum is great!
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Old 04-16-2007, 08:19 PM   #2
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Clutch slippage: rpm rizes but no increase in speed.

As shipping to my country is expensive i changed my clutch to a 1.8 (also need flywheel) Holding 8psi on a 1.8 , and 15 psi on the 1.6...But maybe just lucky...

Yep you are right if the clutch can't hold torque it slips...
Happened to my 1.6 clutch doing about 4000rpm @6psi.(greddy sweet spot)
Clutch was totally gone...(120.000miles)
If the clutch goes , it goes. Normally you can run a good clutch for about 20-50k miles (playing with turbo's youll need a better one.)
Be carefull of your rear diff, they break at oem powerlevels... Start ebay-ing
for 1.8 dif parts...=> 1 drive shaft , 2 half shafts, and the diff.
Prepare to pay 300 alone for a complete diff , axles are not so expensive, but these are a bit rare...Maybe you get lucky @ a local junkyard...(complete set 400-750 dollar)

1st things first...

Where are you now?? Just a basic greddy with ic??
Do you have a larger downpipe??
What are you going to do for engine management(fuel/timing)

With a base set 1st upgrade b4 anything mounted on the car must be the relieve cuts and grade 8 studs(mani/turbo/dp)

2nd upgrade would be adding an ic.
3th upgrade add larger exhaust (2.5"or bigger)
4th upgrade would be a bov.(recirculating, if no stand alone ecu)
5th engine management/ or begi regulator with walbro 190lph hp fuelpump and bipes timing control.
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Old 04-16-2007, 09:04 PM   #3
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Thanks for the reply greddymx5...

Quote:
1st things first...
Where are you now?? Just a basic greddy with ic??
Do you have a larger downpipe??
What are you going to do for engine management(fuel/timing)

With a base set 1st upgrade b4 anything mounted on the car must be the relieve cuts and grade 8 studs(mani/turbo/dp)

2nd upgrade would be adding an ic.
3th upgrade add larger exhaust (2.5"or bigger)
4th upgrade would be a bov.(recirculating, if no stand alone ecu)
5th engine management/ or begi regulator with walbro 190lph hp fuelpump and bipes timing control.
1) I have the stock downpipe
I have made the relieve cuts, and have 8.8 bolts all around, didnt not upgrade studs into the block
2) yes a have a fmic
3) stock exhaust for now
4) I have a hks recirc bov
5) I have msd timming box, and a fmu

With a larger fuel pump and bigger injectors i think i could see 8psi, but like i said i dont want to have to replace the clutch or rearend untill the end of summer... if you were slipping at 6psi, and i want to do 5psi (and redline it) maybe i should hold off on putting the turbo in... And this summer was looking like so much fun!!!

car just went over 150000km last week, i have had it for a year and a half, no idea when the clutch was last replaced.
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Old 04-16-2007, 09:09 PM   #4
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clutches start to slip because the pressure plate can't hold the clutch disc against the flywheel as the torque increases.

most aftermarket clutches acutally use the stock disc with a heavier pressure plate.

what will happen is, youll start to accelerate, build boost and the RPMs will skyrocket and the car won't accel. It's basically engine "wheelspin".


Install the kit now, get familar with it and the components, the worst thing you want to do is up the boost without understanding fuel/timing demands. The clutch should hold up with the boost off the shelf, start saving for the clutch swap and get it done when you can, in the meantime, keep reading and learning and peicing stuff together.
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Old 04-16-2007, 09:46 PM   #5
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My stock clutch held fine at 6 psi, which was apprx 160 rwhp / 150 rwtq. No hint of slipping after 6k or so boosted miles.

Shortly after a few upgrades and going to 9-10 psi and appx 200 rwhp / 180 rwtq, my clutch began to slip. It started by slipping in 4th/5th gear on the highway at/near WOT, and progressively grew worse. It got to the point where when hot, the clutch would slip with only moderate boost in pretty much any gear.

Had I not increased the boost, I'm sure the original clutch would have lasted much much longer.
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Old 04-18-2007, 06:16 PM   #6
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Thanks for the input guys!
Based on what you have said i will install it, run 4 or 5psi... and learn about fuel timming and deal with any problems that might come up, plus upgrade along the way.
I was going to install on this friday, sat, and sun, but i have not run a compression test or a leak-down test... the motor seems strong and i have never had any problems, should i hold off and run the test, or just go ahead and install.

Thanks for the help so far guys
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