well i have the rb header and presilecer with stock piping with rb mufflers...if i get the piping custom..into a y pipe...maybe like 2 in a quarter inch how much h.p. do you think i could get? Thats just with the piping...thats all i need to make a full exhaust...

 

IF you mean your increasing the pipe after the y-pipe to 2 1/4" back to the mufflers then no, you won't gain any HP. Unless your engine is ported pretty good then you might gain a few. Stick with 2" after the Y and match it the the outlet of the presilencer which I believe is 2.5". Or you could by the Racing Beat Y-pipe since everything else is already RB.

 

why would i by the rb y pipe id i get no h.p?

 

the exhaust tubing used should match the size used in the header if ur going with the long primary system. otherwise, from header to single pipe, it's whatever the math is to figure the I.D. for the tubing after the header. i think the header is 2" I.D. so that into a single pipe to yield the same volume would probably be no larger than 2.5" I.D.

 

so from the presilencer make the piping 2.5" for positive power gains?