Originally Posted by a12
Is the flapper valve opening small or something and this causes boost regulation problems?
So do the Hx35's also have different size turbine wheels or just different # housings?
both the flapper size and the fact that if the turbine housing is devided it only bypass the exhaust gases from one of the two canals.
You can basically get the turbo with what ever size wheels and housing you wish up to some degree. The super 40 is a "bit" overkill if the aim is something like 400whp.
A combo that is know to work is also HX35 with 56/82 compressor wheel and 58/68 turbine wheel. Housing #12 or #14 (the dimension after / is the wheels bigger diameter) With #14 housing will give 1bar <3000rpms. Even this is quit "big", but dont have so many examples to point from smaller holsets and saabs.