Required hardware
You will need new Genuine BMW crankshaft bolts (SKU: 11227805885). The Genuine BMW throwout bearing is a highly recommended part while in there (SKU: 21517548396).
Required modification
The inlet guide tube needs to be modified for the 420G to accommodate the twin disc clutch design. Instructions are provided by TTV.
The 420G found in the E46 M3 and E39 M5 are finicky transmissions that are relatively intolerant to lightweight flywheels for street use.
They're loud, rattly, and are often coupled with a heavily sprung single clutch to compensate.
A twin disc should give us more power holding capacity, while dividing the required left foot strength between 2 discs.
In this Special Series, I document the Clubsport kit and the GrandAm flywheel.
Enjoy,
- Matt
Been there, done that.