hey all ive done a fair bit of searching but havent found any answers so was wondering if you guys could help me out.

my friend bought a skyline gts4 with an rb20 in it, it has a fmic and a larger turbo (unsure what size, rb25 most likley)

and running 9psi, the problem is that it is still running extreamly slow, something holding it back, it gets beaten by a stock vs commadore with ease, so any suggestons as to what might be holding back the power would be much appreciated

cheers eddie.

Have you taken if to a workshop for an inspection and a dyno run to see where things are at?

You might aswell start there as it could honestly be anything dude as you havent provided much information.

Just because it "feels" slow doesnt mean the car is behaving badly. Depends on what state its in.