BMW 330d :)
Ive noticed a resonance from what seems to be the centre section of the exhaust on my 172 cup. It only seems to happen when you hold the revs at 4k or above or back off the revs.
I was reading through the evo long term tests on their 172 cup and it seems like they had the same problem. Has anyone on here heard of this with their 172/182 or cup?
Cheers
Fraser