draztik

Hey i got a question.. supposivly the IHI RHB5 will be stock actuated at 8 psi.. what if i run a 2 1/4 inch downpipe (kinda smaller) how much will that lower boost? also then technically i can up the boost correct? or will i have too much of a boost spike if i go with a smaller DP? help will be much appreciated

Reddy

a smaller exhaust will not cause you to have less boost, it'll just have slow as ---- spool time. Regulate boost with the wastegate or boost controller and make your downpipe as big as possible

draztik

won't that be kind good for the IHI considering i've heard it reaches full boost at ~3000rpm

draztik

also i'm using the stock o2 housing and then bolting on a downpipe, is that good enough? i'll make it like 2 1/4 or 2 1/2 we'll see.