custom exhaust, need some help Options

[94gtcelica]

i was thinking about getting my own custom exhaust, buy just buying a muffler and having some body shop put on some pipping, but i wasnt sure how thick the piping should be?? any idea??

what would the best piping be for my car for the most permance?? 5s-fe

[Mynzeyes]

QUOTE (K2_Celica @ Jan 5 2003, 10:11 AM)

?? the greddys catback piping is 2.25". i think the tip may be a full 3"... anyways 2.25 is plenty, if you are going into moderate modifications under the hood on your 5s you should probably go 2.50" and get a highflow cat or replace it with a testpipe. 3"+ and youll run into backflow problems. my friend got i think 3.5" piping on his eclipse and he has major backflow problems, his car is considerably slower than it was before the exhaust system. he has no worrys though because hes going to turbo it this year. all im saying is without FI youll have problems going 3" or bigger...

yep. 2.25" is as big as you need on a non-turbo engine.
-John-