Hey guys, had Kleeman headers installed and a buzzing/kazoo sound is coming from the tail of the car. Thinking it was the muffler, I changed to an aftermarket muffler but there annoying metallic sound continues. Had several mechanics indicate this is normal due to the higher airflow, albeit the metallic sound. I even stood under my car while mechanic revved engine and the metallic sound occurred from muffler. I repeat- I thought it was the muffler but I replaced the muffler and sound still occurs. Could the high airflow really cause this metallic sound?? Note there are no leaks and no loose heat shields!

So frustrating!

 

Is there a resonator? You sure there's no leaks?
There's some video for a bmw 'rasp elimintor' ,
check it out and see if that approximates what you
are experiencing.
I put a resonator on after installing header to reduce that rasp.
See my sig.

Alas the header and the AR20 are gone now.
AR20 cracked and I had it removed, and header removed for smog.

 

Did the reasonator help a lot? What reasonator model did you use? My guy at Midas suggested the same thing, but I worry about increasing back pressure