Mike Gurney,
if you were to look at 1 bar boost (2.0 pressure ratio) the turbo will go into the surge area as the car is processing approx 100 bhp
(has anyone got a dyno plot of a stg1 4x4 cos ?)
Nice of ya to add that after my reply Mike, even nicer of ya to leave it like that so i look a twat!!...
SO how do you figure we are in surge at 100bhp mate?