2001 Boxster, 2.7l manual 119k miles.
The exhaust system is all from TopSpeedAuto, with the headers, midpipes, and muffler.
*Protip* Never change the headers on your Boxster. Trust me, not worth the hassle. If I had a time machine I would stop myself from doing this. But I'm past that point now.
Anyways, so I recently "finished" (i.e. spent too much time and energy) my exhaust by installing TopSpeedAuto headers. The system has no cats. Feel free to bash me for ruining the environment.
The system is probably 5% louder than I would like but whatever, I'm stuck with it now but honestly its fun and rowdy when driving in the higher RPMs.
My only gripe is a new noise that I can best describe as a "clattering" or chugging almost at low RPM's from the drivers side header. Or that's where I think it's coming from atleast.
https://youtu.be/GsKi9Rp5-lw
The noise goes away over about 2.5k RPMs while driving. You can faintly hear it when accelerating from about the 2k and up range when driving. And the noise can't be heard (or is faint enough it blends into the ehxaust noise) when the car is on a lift and running.
It's most prominent when going from a stop -> first gear. First and reverse are both the same volume level for the noise.
My first thought was an exhaust leak, but on 2 different occasions we've had the car up on the lift listening and feeling for an exhaust leak and we can't find anything. The header bolts have been retorqued to factory spec twice now. We've removed and reinstalled each exhaust clamp, and I even installed the Torca Easyseal clamps to replace the factory midpipe clamps. The O2 sensors are tight as well. I also installed Car Chemistry baffles to reduce some of the raspy sound, and those are clamped where the Torca easyseals are located. After a good 2 hours of revving and listening with two other people helping, we couldn't find a leak anywhere. And again, the noise isn't present when the car is on the lift and revving.
I'm stumped, any insight on what's causing the noise?