I have a (some what mild)full bridge series 4 TII motor and would like to get 400+ @10-12 PSI on pump gas... is it possible and what turbo should i be looking at. I am thinking the Garrett GT40

 

GT42 can do it but you got some lag there.. just use the GT35R and have some more fun on the street

 

I have 410 at 13/14 psi, on a "medium" sized 63-1 Turbo. What's the big deal about running 10-12 psi?

 

I personally haven't seen a dyno making that much power at that boost, but I think it would be possible @ 12 PSI if you rev it high enough and somehow manage to keep the airflow very high. Not too many people have a lot of full bridge (or even half bridge) experience on here I don't think. That includes me

In order to get the engine to flow 400 rwhp worth of air, it better be really moving some air! This means low restriction exhaust turbine... high rpm... etc.

As others have said, what's the hangup on only 10-12 PSI? 14 is VERY safe on the street if you properly tune.

 

actually there is no reason for the 10-12 psi i just figured if i said 1 bar... then people would say why the 1 bar max .... I am willing to go to 1 bar. I figured i could get 420ish at 14 psi with the right turbo.

I am also looking at this from a cost basis and for the time being the ball bearing turbos are a bit expensive... but if i have to then i will fork out the extra cost

 

9.7:1 compression rotors

 

I made 403 rwhp at 14.2 psi with stock ports on pump gas. Im pretty sure with a good street port you could make 400 at 11psi. But again 14 on stock ports is enough for 400 and plenty safe so who cares..