Hi;

I have recently built the block on my APS TT. I’m boosting 18-19psi and I should be close to 600whp now. I also have an ATS dual-carbon clutch (had it for ~40,000miles). I’ve had my clutch completely slip on me a few times: at full boost around 4700rpm, the RPM went to redline with the car not accelerating and I left white clouds behind. This happened about 5-6 times in the last several weeks. In itself, that is pretty serious, although it’s not happening all the time thankfully.

But I also suspect that it’s slipping a little bit most of the time under full boost. If I leave my traction control active, the TRAC light will flash in 4th and 5th gear at full boost. I’m pretty sure it’s not spinning the rear tires (305s r-coumpound). So my question is: when the clutch is slipping, does the TRAC light come on?

I’ll talk to Sharif at Forged Perf to get my clutch beefed up.

Thanks!

 

So, does anyone know?

If the VDC is active and the clutch slipping, does the SLIP light come on or not?

Thanks!

 

I have no clue but good luck.

 

Thanks! I'm just trying to figure out why the SLIP light would come on at WOT (full 18psi boost) in fourth and fifth gear. The rear tires can't possibly be spinning at that speed!

 

If you are leaving traction control or VDC on, I highly doubt your clutch is slipping. I only have traction control on my Z, but if left on, I can't go anything more than about 1/2 throttle before it starts kicking in...... but it never feels like a slipping clutch to me

my thought is your vdc or traction control is kicking and you are mistaking it for a slipping clutch. Your tires may not be spinning, but they are turning (accelerating) out of the parameters programmed into your vds or traction control system. Thus making them think your tires are spinning and the systems kicking in.

Try running with the VDC and traction control systems completely off and see what you have. If properly warmed up, I doubt your clutch is slipping.

No it does not come on due to a clutch slipping

 

Hummm... OK, thanks a lot. With VDC off, I can not normally feel the clutch slipping, but it did happen 6-7 times where the RPM went to redline suddenly with the car not accelerating anymore.

 

Paul, I think I'm having the same issue with my Exedy Twin. I realize you need to warm it up a little for WOT pulls but recently it's been slipping much more and I've been redlining as well in 3rd and 4th gear, with or without my VDC on. My clutch only has 10,000 miles on it and I've never tracked it.

 

I have a twin disc that will slip from time to time when it is not warm (3k rpm's to bouncing off the rev limiter in a split second).

With that said my car falls on its face with VDC is on if any boost is built. It will show slip and act an ***. If i leave it and and do this a few times, it will show a permanent slip until i restart the car.

 

My GTM Exedy Twin has around 8K miles on it. It has started slipping occassionally shifting into 3rd at WOT. It does not slip as bad as you describe in your post.

On my car, if the clutch is properly heated before WOT then I have never experienced a slip to date. When it has slipped the revs have not gone to redline. What happens is you feel a loss of power and torque and you can see the rpms going higher but never get above 5K rpm. On my car this heats the clutch and it grabs and thats the end of it. After it slips once, you cannot get it to do it again.

I'm at 511whp DD.

 

Mine will continue to slip like I mentioned for 3 or 4 WOT runs before it really grabs. I can't believe it could be failing already. I've never been on a DD, but I figure I would be around 450-475whp on that dyno.