So I just did a b-series swap. (B20)
It's hooked up to my 1.5 inch civic exhaust (92 VX hatch).
Just wondering, if I went to a 2.5 inch exhaust would the gains be more than just a couple of whp. (i can get a custom 2.5 inch catback with apexi n1 muffler for 150)
I'm hoping 10whp.. cause 1.5 is really restrictive.

You guys have any dyno graphs of stock civic exhausts vs. aftermarket? I searched but couldn't find anything.

 

If you dont have a header then you might see 2whp gain.

 

running a stock LS header to the 1.5 inch civic piping.

 

Might as well keep the exhaust then. Or if you dont plan on upping the header a 2.25 will be better then stock. But you wont see 10whp.

 

alright, I just got a DC 4-2-1 stainless steel header and GSR midsection with no muffler and put it on... there's a small difference, but I guess a big enough of a difference that my clutch slips from 1-2 shift.
best thing about it all is I got the header for $50 used, and GSR mid for $10.. lol.