Hi guys, what boost do you run for a health 400bhp on a cossie yb? I'm trying to figure out weither I have selected a suitable turbo for my project but cannot figure out the pressure ratio needed for the compressor map.

I know I need 40-42Lbs of flow but @ what pressure is the thing I cannot figure out....I think this might be unique to each engine...as a few psi on one engine is more of a gain that on another etc....

I have a ported head (inlet side mainly) I think theyre 2-3mm over std when I measured them a while back if that makes a difference to boost required (I read so many times that boost is a measure of restriction not flow )

Cheers
Dan