Clutch Smokes / Smells at High Speed
 

Hey guys,

Car: 1990 S5 TII; heavily modded (see sig).

Clutch: ACT Xtreme Pressure Plate, ACT Unsprung Performance Organic Street Disc. Got about 20,000 miles on it.

Flywheel is a racing beat aluminum. Throw-out bearing was replaced about 500 miles ago, tranny fluid at the same time. Clutch seemed fine at that point. Stock Tranny. New engine, still in break-in period (not boosting it at all, nor high rpm's).

Anyway, I've been driving my car around town with no real issues. Shifts fine, runs completely normal. Yesterday I was driving it and I noticed after about 20 minutes a very faint clutch smell. Today, for the first time in a few weeks, I hopped on the highway and immediately the clutch started smelling really strongly, and I had smoke coming out of the shift boot. This issue seems to be directly related to speed, or at least that's where the symptoms show strongest.

I'm thinking it's always slipping a tiny bit, but you can't tell on normal street driving; it's only at high speeds that you notice it. I'm a little rusty on my clutch knowledge; does this mean my disk is wearing out? Pressure plate? I talked to my mechanic and he said off the top of his head it could be a hydraulic issue with the slave cylinder.

What are your ideas?

Thanks for help in advance.