UPDATE: Re: SLP Flywheel / SPEC II clutch and vibes...>>

[Jay 95 T/A M6]

OK..here is the update, things are better but still not perfect. I had the U-Joint rotated 180 degrees on the rear axle..took the car for drive, and the noise is reduced (almost to a livable level)...I took the car for its first highway drive and I have a "body" viration around 90-100mph..I've had this problem before, and it turned out to be my carrier bearings in the rear end were shot. Anyways, to see if its the clutch, I put it into nuetral (at 90mph) and let the engine idle...VIBRATION is still there. So I guess this means its not the clutch setup, but something else, and the only thing I can think of is the rear U-Joint. Its the only other part that was removed from the car. Is it possible that the u-joint was not bolted up perfectly, and is causing the vibes? I have a new one on order and will have it installed tomorrow.

Any other takes on this?

Jason.

[Jay 95 T/A M6]

FIXED...finally, SLP lightweight Spec II vibe problem...FYI for others>>

First off, thanks for all the reply's to my recent weeks problems...here is what ultimately fixed my vibe problem after Spec II / SLP flywheel install.

1/ After install, had vibration/rattle problem under low RPM load. Replaces U-Joint (rear) and had Alum driveshaft balanced. That fixed the 90mph vibration problem.

2/ gave up on the rattle. After conversations with SLP and SPEC (they each blame the others product...thanks for the help) the only advice was to switch to synthetic fluid. I did not do this yet.

3/ After about two weeks, I'm cruising down the highway, and get a SES light. 65mph 6th gear...just cruising, no noticable problem..just a light. I stop the car, shut it off restart and no light. ok.

4/ Next day, same problem..same speed, 6th gear..etc. (The entire ignition system was replaced last fall..NEW everything.) hmmm.

So..I'm searching everywhere on the net, and come across a site (can't remember what it was) but it discussed harmonics and engine balancing etc. They went on to say that an LT1 motor(neutrally balanced) sometimes suffered from a misfiring #8 cylinder. This would cause problems.

So..tonight, I let the car cool down, dig down to have a pick at #8..low and behold the plug was loose. I could spin it out with my hand. This was the only plug that was loose (reachable ones) and it was quite white on the tip. So I replace it, tighten it down go for a ride and rattle / vibes totally gone. hmmmm...

It appears that the problem may have been there for a while, but with the stock Iron flywheel, the rotating mass compensated for it, changing the rattle frequency to something other than what I was experiencing...with the lighter clutch setup, the noise attenuated to a RPM that was much more noticable. 1500-1800..

Anyways, thought I'd pass along my findings. Thanks again for everyp) the only advice was to switch to synthetic fluid. I did not do this yet.

3/ After about two weeks, I'm cruising down the highway, and get a SES light. 65mph 6th gear...just cruising, no noticable problem..just a light. I stop the car, shut it off restart and no light. ok.

4/ Next day, same problem..same speed, 6th gear..etc. (The entire ignition system was replaced last fall..NEW everything.) hmmm.

So..I'm searching everywhere on the net, and come across a site (can't remember what it was) but it discussed harmonics and engine balancing etc. They went on to say that an LT1 motor(neutrally balanced) sometimes suffered from a misfiring #8 cylinder. This would cause problems.

So..tonight, I let the car cool down, dig down to have a pick at #8..low and behold the plug was loose. I could spin it out with my hand. This was the only plug that was loose (reachable ones) and it was quite white on the tip. So I replace it, tighten it down go for a ride and rattle / vibes totally gone. hmmmm...

It appears that the problem may have been there for a while, but with the stock Iron flywheel, the rotating mass compensated for it, changing the rattle frequency to something other than what I was experiencing...with the lighter clutch setup, the noise attenuated to a RPM that was much more noticable. 1500-1800..

Anyways, thought I'd pass along my findings. Thanks again for everyones help..i've been paying attention here for years, however only speak out occasionally.

Jason.

[M3EATER - GG '00 WS6 T/A]

Hmmm.....
Good work tracking that down, Jason!