Picked up a new 2008 Z06 a little over a month ago. Noticed a tinny (as in the metal not "small")vibration coming from the rear (maybe passenger's side rear) the second day I drove it. It does not usually happen until the car is warmed up. It picks up at about 2800 RPM and continues through around 3500 RPM in 1st, 2nd, 3rd, and 4th. It doesn't usually happen on hard acceleration but with light to moderate accelerartion it occurs pretty regularly. If I had to guess, I would say heat shield, exhaust line rubbing,or internal muffler vibration. I took it by the local Chevy dealer a few days after I noticed it (not the same dealer I bought it from). They heard it too and were guessing the same thing. On the lift, they could find no rubbing/loose parts. I told them I would drive the car til about 1000 miles and see if it went away after a few heat up/cool down cycles. It's still doing it with 1100 miles.
Does this sound familiar to anyone else? With the few moving parts in the muffler, I was wondering if they should just replace the mufflers or go for the entire exhaust line. I'll just have to take it back to the local dealer or the one I purchased it from and see what they're willing to do. I just thought I would get some opinions first.
Thanks,
James

 

With 1100 miles on it, someone determined ought to be able to see the rubbing spot if they really search for it from underneath the car.

Have it put on a lift that keeps the suspension compressed (the type the car drives up on and is lifted via the tires, not the type that lifts on the lifting pucks) this will keep the clearances as the are when you are driving. If it were me, since this happens under gentle acceleration, I'd put an 80 lb bag of sand in the trunk, too, to simulate the slight rearward weight bias you get under those conditions, even though I suspect the acceleration-related issue is not due to rear suspension squat but to the engine torqueing over during acceleration and twisting the exhaust slightly.

Good luck.

 

Thanks for the help. It was a drive up lift that they put it on last time but they did not load the rear suspension. It's too bad that they don't make a dyno/lift combo, though it would get a little more dangerous. I'll just have to let them try what they can and go through whatever steps they need to.
Thanks,
James