i want know what size piping is good for stock GSR engine. iam not plan to upgrade cams or anything, just plan stock b18c1 with intake. so is it 2.38 makes good power than 2.5 inch?
please dont guess, i also heard 2.5' on stock b18c1 will loose torque?? and flow mess?? if someone know about this please share.

header<car<exhaust match up size.

or 2.5<2.5<2.38

 

power per dollar - stick with a stock itr catback. also, the cops will not harass you.. and since you're sticking stock you won't see much power difference between the itr exhaust and a custom 2.5

custom - 2.5 mandrel bent owns.


edit: you won't lose torque at all, you'll gain. i went to a 2.5 collector on my edelbrock header and gained midrange/torque like a muhfuccer.. so i don't see how 2.5 piping can hurt you at all.

 

the reason i said 2.5 on stock motor will hurt HP=TQ. there is something about that bigger pipe on engine that dont need bigger pipe will loose toque. so someone should clear this up.