so i just bumped a thread about this, but doubt anyone is going to read the whole thing and see my post at the bottom of it..

anyways, last night my exhaust started making a nasty resonating noise around 3 or 4k rpm.. it almost sounds like a straight piped civic, all rattly and gross sounding..

i could sware it is coming from BEFORE my rb tip, and not out of the actual tip itself. hopefully it is just a leak, but i kinda doubt it.

i'm hoping my motor isnt taking a **** on me. it is rebuilt with around 30k on it.. i should probably add that it is straight piped(SDJ header, custom pipe all the way back to RB tip) and it has always had a kind of rattly noise around these rpms, but not it is WAY louder, and very frustrating..

 

is your exhaust clamped up to the car correctly?
There are 2 shields by the gas tank,one on each side that can break loose and make a clatter.

 

you mean like the hangers? all the hangers are hooked up correctly.. it almost sounds like theres a rock in the muffler vibrating somewhere.. i'm hoping it's just a leak, but if it was a leak, wouldn't the sounds be consistent and not only from 3-8k rpm?

 

it seriously almost sounds like this

http://www.youtube.com/watch?v=bSJBCS430c4

 

have you even gotten under the car yet?

 

muffler baffles could be blown out. heat shields could be rattling. you really need to get under the car.

 

Getting under the car was the first thing I did..

I checked for leaks.. my exhaust is only 3 pieces.. header, straight pipe, tip.. so it didn't take long to find that there was no leaks.

I'm just hoping it isn't anything inside the motor, and I can't really see what it could possibly be. But I am a pessimist and I'm going to assume the worst

 

Listen to the car while it's running, do you hear any sounds coming particularly from any of your possible leak areas? If not, then listen to where the sound is coming from. It should only be the exhaust tip, and then the motor itself right?

Beware, cheap or loose exhaust pieces inside an RX-7 can be destroyed causing all sorts of crap to happen...

 

Before you fire the car up crawl under the rear of the car and bang the muffler with your fist. You should hear the rattling quite easy. Pin pointing it will be the fun part!