Clutch slips under boost... but only in 1st gear

[XpL0d3r]

Had this problem before, but it was with an OE clutch. Went out and got a Competition Stg 2 clutch. OEM flywheel (yes, it has hotspots).

Clutch seems to slip under boost in 1st gear. Drives fine until I get on it, and once the turbo spools, the RPM's fly up like I'm just revving in neutral, and I go nowhere. It's a JDM B18B, ~9.5psi on a 50 trim.

Clutch is only ~ a year old, so it should be good. I'm not sure if it has to do with the hot spots on the OE flywheel, or if there's anything else it could be.

Under boost in any other gear, the clutch seems to hold fine.

Any thoughts? Thankss y0.

 

[got traction]

without hearing it happen, i cant give a definate answer. But, i think you already know whats up. It could be that the spring fingers dont have enough clamping force on the initial hit. Is there a way you could data log it and post it up? or if you have s300 you can email me the file and i can take a look.

 

[got traction]

what did the torque curve look like on the dyno? does it only happen when cold or when the clutch is already hot? does it happen at WOT in 2nd or 3rd gear?

another thing to look at would be whether or not your in that zone where it doesnt make enough torque to spin the tires and is just simply overpowering the clutch springs

 

[XpL0d3r]

I'm actually running Neptune, and don't know too much about it or tuning in general haha (meaning I have NO idea how to datalog...). But, here's an old dyno graph... note that this was with a very dirty fuel injector, and I have had it retuned since, though I don't have the new graph (it's probably pretty similar?)

Someone had also told me this:

The stg. 2 disc is only rated to slightly over 200lbft of torque. You are probably exceeding this rapidly in first gear acceleration. The longer following gears likely are not shocking the clutch due to the more linear delivery of the torque.

And another friend said it could simply just be tire fire (I doubt this....), or just because the flywheel wasn't resurfaced when I installed the new clutch...

It doesn't happen WOT in 2nd or 3rd though. I'll verify this in about an hour though
I'm about 90% sure though because last week I got romped on by a g37s from a light, but killed it from a 30mph roll

 

[RonJ]

...the flywheel wasn't resurfaced when I installed the new clutch...

It's hard to ignore this^

 

[obracer12]

the flywheel not being resurfaced hurts the lifespan of the clutch... any NAPA machine shop will do it for 20 bucks...

you're probably peaking more torque than that from a stop and it's breaking the clutch loose.

These 2 things combined = a dead clutch shortly.

 

[got traction]

we've used the 1.5 comp clutch on cars that make well in excess of 200ft lbs of torque without slipping. I think your issue is a combination of weakened pressure plate springs and the flywheel surface being glazed from the previous clutch. You could pull it apart and resurface the flywheel and take a scotchbright pad to the pressure plate. Put it back together and so what happens.

 

[XpL0d3r]

Hmm alright I can do that eventually and see if that works.

Thanks!

 

[DarkCreep]

Why didnt you resurface the flywheel? Best $20 ever spent lol.