My car has headers with 2.25" collectors, 2.25" test pipes, 2.25" to 2.5" Y-Pipe and a mandrel bent 2.5" exhaust with a 2.5" straight through magnaflow muffler where the stock midpipe went and a 3" magnaflow straight through race muffler at the end.

The car feels great but I'm, really not happy with the rasp. The sound level is perfect for me but I would like to remove the rasp without affecting flow...is this possible?

 

If your exhaust is dual at any part (although you have a y-pipe so I don't think so) you can try and weld a support piece between the two pipes to prevent some vibration, or you could add a resonator?

 

Sounds custom....your muffler shop couldn't figure this out?

 

which model race muffler. without knowing which atcual sized parts were used, its hard to make a suggestion

 

I didn't do it in a muffler shop. I had a friend help me weld up the exhaust. I came out great and was tig welded but the sound isn't what I expected. It has way too much rasp.

This is the mid muffler I'm using:
http://www.magnaflow.com/02product/s...e=main&id=7968

And this is the rear muffler:
http://www.magnaflow.com/02product/s...e=main&id=8181

I had this same exhaust ( minus the mid muffler ) with the stock manifolds and stock cats and it sounded great. I installed headers and test pipes and the sound was mind boggling loud so I added the mid muffler. Sound levels are great now but it has a lot of rasp.

I've read a lot of people having the same problem and I'm just wondering if the only solution is to add cats again.

 

People are using resonated X pipes to rid themselves of rasp on their duals. Not sure how you are going to handle this with your single.

Resonated Test pipes might be in order.

 

Go back to the stock catback. You'll be much happier. With everything you'll need to do to kill noise and rasp, you're really going to choke the exhaust. Consider adding some resonated exhaust tips. They will actually help clean up the rasp.

 

Dave. If this guy has headers, I think he's beyond the stock cat back IMHO. But that race muffler isn't doing him any favors.

Question is is the rasp coming from the front or back?

 

lol...correct...I live with the rasp before I go back to stock.

What do you mean by your question though?

 

resonated test pipes might work. If not, you might be limited to hi flow cats. IMHO, there's not much hp diff inbetween test pipes and hi flow cats anyway

 

How about when supercharging? I plan on supercharging my car and if there is a decent amount of power lost by HFC then I'll live with the rasp. Resonatied test pipes don't sound like a bad idea though.

 

You really haven't gained anything with your catback. The resonator and muffler really aren't that restrictive to begin with. If you want to tone down the rasp and volume, the stock catback is the way to go without compromising much power at all. A lot of your rasp is coming from that muffler, no resonator, and those TPs. They're all doing thier fair share. Go after the parts that don't effect power much at all, the catback.
Consider the HR y-pipe or MD XYZ pipe with the resonator as well.

 

I think MD is coming out with something new for test pipes that does a great job of eliminating rasp. PM Hydrazine.

 

Well, after driving the car some more a lot of the rasp has gone away. Do mufflers "break in"? Seams to sound much better now.

I'll look into those MD test pipes.