I've got true duals dumped on my car, 3 inch X pipe, magnaflow 4x9s. I huge the tailpipes of the mufflers with good exhaust hangers up to the rear seat belt holes. From ~1600-1900 rpms I get a "waaaaooooo" humming noise from what sounds like the rear passenger side of the car. Even though I have poly mounts I thought maybe the muffler was hitting the bottome of the passenger rear seat well, so I stuffed a rubber bumper type thing in there to see if that was the case. No dice. Anything else I should consider before I say "F' it" and go back to a catback? A couple people suggested that it might be something to do with the way the air hits the bottom of the car or something. Any ideas?

 

It might just be the car resonating in those rpms. Mine does it, and I love it.

 

Hmm, I'm probably going to run it out the back this winter but maybe putting some turndowns angled outwards 45* might help until then......(ordering them now...)

 

yeah mine are angled 45's and i dont not have this problem