setup is as follows:

b18a1 engine. std size itr pistons, p&p head also with 3-angle valve job, kms springs and retainers, 4-2-1 header, hondata style gasket, msd ss blaster coil, cap and spark plug wires. ecu chipped by j.w. racing. bisimoto cam gears, +2 in, -1 ex on oem cams.

now for the question. i'm slowly piecing together a exhaust upgrade. i'm thinking on going 2.5" diameter. but i don't know if it's too big of a diameter, and i should stick to a 2.25" diameter.


please discuss.

go with 2.5.

^^x2 The only time you really need to worry about loosing velocity (going too big) is in the header tubes and the collector. Those are the only places where keeping velocity really counts. After the collector you can go "2.5.

you honestly could go even a lil bigger to like 2 3/4" i have seen really good results with skunk2 MegapowerR exhaust (2.75") on all motor cars