what diameter pipe for for custom exhaust?

im building a custom exhaust for my 96 GSR. with all the recent talks about back pressure i am confused as to what diameter pipe i should use for my exhaust system. my car is N/A and with no plans for forced induction. only other current mod is short ram intake, with a header to be added later. any suggestions?
thanks

I suggest that you use 2 and a half inch piping. I've heard a lot about the backpressure stuff also, and from what I hear 2 and a half is the best size because it provides enough backpressure to keep the pressure inside the engine at optimum levels but enough opening to leave the engine clear of too much air pressure. My friend has an 03 Civic Ex and He got custom exhaust with 2 and a half inch piping with an AeroSpeed muffler. The guy he got it from told us what I just said at the beginning. Maybe it's, bigger is better:confused: but I just heard 2 and a half was the best.

i would only goto a 2-1/4" pipe, thats about as big as a NA motor will use correctly, before you start losing power. 2.5" and up are for turbo cars, or cars with Big Blocks in em.

:iagree:

civiclvr is probably right about that one now that I think about it....but if so, then i wonder why my friend was told that 2 and a half was the best and that it wasn't until 3 inches that it was for Engines using Forced Induction?? I'm not the smartest when it comes to Exhaust Systems. I know a little bit but he knows more..:twak:

does any one know what diameter the stock exhaust is on a GSR? i have no idea... i thought that it was 2.25in but i could be wrong.
thanks