Hello! With a question...
 

Hey guys, glad to be joining the community here and will be sticking around for sure. Posts on here have guided me (I believe) in the correct direction and I've just purchased an 03 Boxster with a fresh engine rebuild, IMS bearing done, bores clean, no debris or sparkles in the oil after the first change. I love the thing, it's an amazing piece of machinery.

I do have a question though, it seems like the exhaust is making an absolutely stellar racket even when I'm driving around, sounds like popcorn popping south of the first set of cats. Car cleared emissions with no problems, no CEL, motor doesn't hesitate or run rough ever, exhaust heat shielding is all intact and solid, but my god does the thing ever make a boatload of noise coming out from the exhaust, both while running/driving and for about 10 minutes after I turn the motor off.

My thoughts are maybe the muffler baffles have gone through so many heat cycles that some of the material in there is starting to seperate and as it heats and cools maybe some broken welds in there are cranked against each other. The noise isn't in time with the motor, but does speed up as revs increase, which makes me think maybe theres some bits floating around in the muffler, possibly from the rearmost cats.

Is this normal for these Boxsters to make such a racket? Has anyone else experienced something similar to this?

No...............

I'll be a little more clear - it's the sound I expect to hear coming from an exhaust after I turn any given car off, but it's more frequent and can be heard while at low RPM and driving slowly, like in first gear through a neighborhood or driving past a car in a parking lot. It's not a major concern per se (I'm a GM mechanic and am familiar with plenty of scary engine noises) but it's annoying as hell. I'm just trying to figure if anyone else has some thoughts on it.

Still no...

Alrighty. Diag time.