BGTV8 needs a new clutch

chops

im guessing your clutch is fine. its just the clutch fluid boiling since the cable passes directly over the cats. flush with RBF600 or castrol SRF and add a stainless steel line. you'll be set

BGTV8

Nope, clutch is slipping. Boiled fluid means you cannot pressurise the clutch circuit and properly disengage the clutch to support shifting as the air-bubbles compress rather than the CSC pushing on the pressure plate fingers and disengaging the drive.

The dead-giveaway was the stink of the clutch which indicated that the flywheel was rotating faster than the clutch driven plate - engine speed was higher than it should be for the road speed.

I have experienced slipping clutches before and this is a classic case and the smell of burnt clutch driven plate facing material is a dead give-away.

Either the pressure plate fingers have lost tension (unlikely as they usually collapse entirely) or the facing material has worn which is the most likely.

Given that this was my first session at Sandown which has an (up-hill back straight) with the 4.08:1 final drive gears - which means I am pulling higher RPM for a given road speed/gear combination, I am actually putting a bit more torque thru the clutch at a given road-speed which may have contributed (remembering that the function of gearbox and diff is to
"multiply torque").

The other factor is that the car has covered ~ 120,000 kms and done a heap of track days - well over 50, many of which involve standing starts (our club-sprints are paired standing starts with the field gridded in practise time order and each pair starting 6-8 seconds apart for a 6-lap "dash").

These "super-sprints" do not qualify as a "race" because it is not a massed start with everyone stepping off the clutch when the lights go green, but the I still still launch the car in race mode, and the fact that the OEM clutch has survived the brutality is in its favour.