Hey guys, I have an 04 RX-8 AT with MS CAI and GReddy exhaust.

I've noticed in the last month or so the exhaust no longer produces the sound it used to in the higher RPMs. At lower RPM's it is still quite loud, but before this I could usually hear when the 3rd and 4th ports open in the engine, as the sound intensity increase was pretty obvious.

Any ideas on what the issue is?

 

My exhaust was really loud when I first put it on, and after driving for awhile they start to tone down from the carbon. I don't think you should really worry unless your car is acting funny.