Hi Guys, I posted the following post in the Cayman/Boxster forum as well but I figured I might find some help here as well. Please let me know what you think.

So I am looking for some help on this because I can't really figure it out based on the symptoms, so hopefully you guys can help me with this.

I have a 987 Cayman and a 987 Boxster (with a TPC turbo). This weekend my brother (the boxster is his) hopped into my car and did a 4000 rpm launch (completely dumped the clutch). PSM was off. Lets just say it wasn't the best launch and as soon as the car was stopped the smell of clutch was apparent. I have Michelin Pilot Super Sports on the car that are less than a year old and havent seen track time yet so I would say they probably have about 90% of their life left on them, which probably did not help, because they stick real well. Now to the problem....

The clutch is (was?) in amazing condition. I have the car almost 4 years now (its an 08) and I do not do burnouts, launches with it. The clutch still grips at the exact same point it did before he launched the car, it does not grip any higher. It does not slip and the car shifts perfectly fine. If anything the grip point feels like it is longer, not higher, but longer, if that is possible? The car can still be rolled out without giving any revs and all works fine. The problem is when driving off from a stop, when giving some gas, the rear end of the car will shake where it feels like the top of the grip point on the clutch. I had thought maybe something loosened up on the rear axle, or maybe an engine mount etc but if you give more revs (not a lot lets say 1500, 1600 rpm vs say 1200) the rear end does not shake, which makes me think it is something with the clutch/flywheel? As I mentioned, transmission wise, the car is running perfectly fine outside of this problem. Any ideas?

 

Broken Motor Mount?

 

I was thinking that but it happens at the exact same spot of clutch engagement every time and wouldnt the rear shake under hard acceleration if it was a mount?

 

Is there any ambient temperature component to the shaking. Twenty years ago I had a 325i that did the same thing (except the front end shook) when engaging the clutch but engaging at higher RPM's resulted in no shaking. The odd thing was that it only acted this way at ambient temperature above 80 degrees. BMW never solved the problem and the car went on for another 95K miles with this quirk. Sorry not to be very helpful but at least you know it's not just Porsche that has had a similar issue.

 

My guess would be that the clutch friction has changed. The "grab" point begins at the same point (mechanical parts all working as designed), but lasts longer, and near the end has some minor vibrations ("shaking"). Your brother just changed your clutch life, and you can either live with the vibration, engage differently to avoid it, or go have the clutch replaced.

 

Here's my advice after you sort out the problem . . . . Keep your brother out of the driver's seat.

 

Nope it happens regardless of the temperature! The car idles perfectly fine and shifts normally (I havent really done any hard redline shifts from 1-2, 2-3 at redline feels normal).

 

I think this could be it too. I thought at first maybe the clutch glazed unevenly but this makes sense. And being that I know the grip point so well, if it has changed I could be releasing the clutch a little too fast at the end of the grip point causing the shaking. I havent noticed revs dropping however, I guess I'll have to take it out again and take a deeper look.

 

I agree!! I dont know what went through his mind, but my car was the guinea pig! He has a boxster w.a tpc turbo yet mine was the one being launched!

 

Sounds like clutch chatter. Maybe warped a pressure plate?

 

I'm thinking pressure plate or flywheel. The car is still under warranty, I know the clutch is a wear item and not covered, but if it is the flywheel is there any shot at it being covered? The car has 32000 miles on it.

 

So how did this story end?