Do mufflers rob horsepower?
Do mufflers rob horsepower? Someone told me yesterday that the flowmaster I just had installed is actually robbing horsepower. I thought the muffler was soposed to boost HP.
Flowmaster gets a bad rep b/c it isn't as free-flowing as most aftermarket mufflers (for ls1's). It WILL gain hp over the stock catback, and while it won't gain as much as other brands, it's more for improved sound than hp. The slp dual/dual is considered to be very free-slowing.
Hooker areo, Magna flow, Dynomax superturbo, Walker Dynomax, Corsa Slp daul daul are all the mufflers I've ran over the years Walker Dynomax is the quietest one an didn't rob hp if any.
I just hate the drone sound the DD have. 
