I was wondering if I could get some opinions on what I have so far vs. what I want to do. I am making my own cat-back system for my 2.0 S/C and I have a Flowmaster 60 series delta flow import muffler, which sounds great btw. I am ordering 2.5" mandrel bends to go over the rear but what I am needing is some recommendations on a new resonator. Right now with the stock resonator on it it gets a little raspy and a little bit of a buzz when I get on the accelerator hard and when I get into high rpms. Also, the 2.75" pipe out of the back side of the cat and into the resonator should I keep it 2.75 or make everything cat-back 2.5"?

 

as long as your transisitions from the 2.75 to the 2.5 are smooth (nice reducer) i would think you should be fine leaving the 2.75.

but................ if you are replacing the resinator anyways you might as well just make it all one size. (Thats what i would do anyways.)

 

well I was thinking of redoing most of everything in 2.5, I don't know if opening up the pipe a little bit more will help get rid of some of that buzz or not so thats why i'm looking at a other than stock resonator. I read a few different articles that said something to the effect of opening everything up past 2.5 would actually kill some performance. I have access to oval pipe if I wanted to open it up more in the tighter space.

 

to get rid of the buzz i switching to a better resonator should help some.

on a side note some of the noise might be comming from flowmaster muffler. thats probably not a straight through muffler anyways. on my supercharged 94 gt i picked up 18 whp just from switching from a flowmaster to an slp loudmouth straight through exhaust system.