S52 vs M52 flywheels

[snaponbob]

They are quite different, even though they WILL interchange between engines. Not sure what is different about the clutches, maybe stack height. Anyway ... PICS !!!!!!!!!!!!!

[Butters Stoch]

I knew it.

[snaponbob]

But SOME did NOT.

[sjpgoalie]

Idk why, but I have a feeling that this is why guys with stock flywheels and clutches with e36 Ms complain of resistance when they put the trans into 1st, but 328 owners do not. I figure there are a few differences beyond friction plate.

[snaponbob]

So, after posting the pictures and before installing the ZF in a 96 M3, I took a good look at the 328 and M3 pressure plates. I had to get the box in the car, so only took a quick look at them laying on my work bench. I think the M3 unit is "thicker", and that would make sense after seeing how the two flywheels are built. It may be a stack height thing. Anyway, I will never mix/match ANY of the parts (even though the clutch plates look and measure the same.

[dano670]

How are the weight differences between the two?

[snaponbob]

Did not weigh them. A friend was with me at the time. After I picked up both of them (one is each hand) I noticed the difference in weight. I said nothing to him except to take them from me. "Holy crap!!!!" was the response. There really is a great deal less metal on the M3 flywheel, and it is taken away from where it really counts - the perimeter. I am guessing at LEAST 3-4 lbs. While it may not be apparent when you just drive around a 328 with an M3 flywheel/clutch retrofit, it would matter on a drag strip or race course as the flywheel would certainly take less power to spin up. PHYSICS !!!!!!!!!