The P.O. of my z28 cut off the stock muffler and put in its place an ordinary Flowmaster 40 series muffler with a single tailpipe coming out of it. It looks like crap. The rest of the exhaust is stock. I'm wondering though if this is giving me worse performance than a stock muffler w/ 2 outlets. It sounds all raspy and like crap when I shift. Maybe its too much backpressure?

 

Any ideas?

 

As I understand it, most people who run a flowmaster muffler do so strictly for the sound. Magnaflow, Corsa, SLP, etc. are all pretty much regarded to be better flowing and thus produce more power.

 

i doubt that its hurting any kind of performance. it probably flows better than the stock crossflow muffler.

 

ya, it flows better than stock, but not much. Flowmasters are for sound. I saw a picture where a guy blew the thing up on his car because it was so restrictive, shot the guts right out the bottom. I dont think his car was much more than stock. -Michael

 

My friends mustang made 590 rwhp with dual 40 series flowmasters, so if your car is near stock or with headers, I'd say you aren't loosing too much. Granted, its a horrible sound, but thats subjective.