Everyone I'm baffled, and so is Westchester Mini's service dept. On highways here in NYC I'll drop my 2006 JCW 6sp hardtop into 3rd and accellerate to pass and from approx 4,800 or so right up to redline I here this strange resonance/vibration coming from the rear of my Cooper. I do not hear it upon deceleration in these rev limitis, just acceleration. I don't know if this is a JCW exhaust issue or what, but they couldn't find it and I hear it a lot considering I have to drive aggressively to pass some people here on the highways. ANY ideas are appreciated and thank you in advance for your time and wisdom.

 

Check the exhaust and the cover under the rear( forget what it is called) I had the same issue and it was just loose bolts.

 

Thanks I'll give it a shot and update what's up.

 

if stock exhaust, check the tip's bolt. might be loose.

 

When the JCW kit was put on my car, I noticed a buzzing sound comping from the back at unpredictable times. When I jacked up the car to inspect things, I found that parts of the heat shield were very close to the exhaust system. Evidently, as the exhaust system heated up and expanded/moved, the heat shield was contacting it.

The heat shield in maleable and easy to adjust for proper clearance. And, as Febmoon1 said, check the bolts while you're under there.

Theo