so yea i have an evo 8 with a 35r kit on it and most supporting mods. i have an upgraded uicp. stock fmic. and full 2.5 custom catless exhaust. i make 405whp @ 26psi. im shooting to make a little under 500 horse which is honestly only a tune away with how conservative my tune is. my question is should i move up to 3 inch intercooler piping and exhaust? am i being bottlenecked ? for the money i can spend on a full fmic kit and exhaust is it really worth it? can i get away with going with just a bigger fmic with 2.5 outlets? my buddy swears by 3 inch, but ive also heard it was overkill and that 2.5 is actually great until like 550-600 horse. what do you guys think

 

The 2.5 inch ic piping is fine but I'd go 3" on the exhaust, that's gonna bottleneck stuff before the ic piping does. I run 2.5 inch ic piping on my car and it made more than 600.

 

i do have an external waste gate dump so thats why i figured it really wasnt effecting it

 

OWG should work fine with it

 

A good flowing 3" exhaust and 2.5" I/C piping isn't a restriction until 700-750whp from the testing I've read over the years.

 

I've got to think a new IC will help quite a bit. I'd run whatever the turbo outlet size it (prob 2") on the hot side, and 2.5" on the cold. I've seen numerous 700+ cars running 2.5" ic piping. As for the exhaust, definitely go 3".

 

You would see Gains with a bigger fmic and 2.5 piping no need to go bigger then that for now.