Resonance in aftermarket clutch.
I have an 2002 S54 in my E36M3 with the E46M3 manual trans. It is used almost exclusively for time trials at the track. I'm running less than stock power levels to make class. The OEM clutch failed after two years of track use. Several BMW enthusiast in my area have had good luck with the FX stage 2 clutch kit off ebay. It has a lightweight steel flywheel and was reasonably priced. Once the unit came in, the clutch itself was a Luk and looked to be good quality. The flywheel and pressure plate looked to be very good quality. I did not used the supplied throw-out and pilot bearings, we they appeared to be cheapo units so I ordered new OEM for that. After installation, the clutch works well with good action. I did notice vibration over part of the RPM range that I was originally attributing to chatter, but after driving it a while I realized it is indeed a vibration. The vibration is from 5000-5500 RPM. Smooth above that and below that. It happens just sitting still in neutral with the clutch in or out. Same results driving, under load, coasting, whatever. This in indicative of a resonance being caused by the flywheel, clutch, or both. It is pronounced enough to give me concern that prolonged use would mean shortened engine life.
A friend, who is a good BMW wrench, has the exact same clutch in the exact same engine and does not have this problem. I think it is probably a defect in the flywheel or pressure plate I have.
As it is such a PITA to change the clutch, I only want to do it one more time. I do like the light weight flywheel as I'm not worried about chatter. I am worried about resonance and vibration severe enough to create other problems which I feel this is. I was thinking about buying an JB racing flywheel /OEM clutch assembly from ECS. The car did run good with all OEM, so that is probably the safer option.
Thoughts?
Last edited by rvsixdriver; 03-26-2018 at 03:06 PM.
RVSIXDRIVER, '11' 128i 6MT, '96'M3/S54, '88'M3/S52 sold
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