right now i got a dc sports 4-1 header, aem short ram, i was wondering what size of piping should i get running back to my fireball exhaust? also what kind of hi-flow cat i should get? thanks.

 

it would help if you decsribed what motor and mods you have. If you have a B series i would go 2.25 for more back pressure or 2.5 if you dont give a rip.

 

2.25 i'll say

 

Yeah, I'd stick with 2.25. With those mods, you won't need anything more than that. Anything more and you'd probably lose power and be loud and obnoxious.

 

my bad, i got 2000 civic si with b16a2. right now i got the 4-1 header, short ram intake, fireball exhaust. should i get a hi-flo cat? and stick with 2 1/4" piping. also soon to be installed skunk2 cam gears and aem pulleys.

 

yeah stick with 2 1/4 piping

 

should i get a hi-flo cat?

 

yeah if you have the money i would definitely get one. i just bought an OBX hi flow cat, which is basically a straight pipe for 50 bucks.

 

b16 i say 2"
b18-h22 2 1/4"
and a high flow cat