NICE hotair intake and intercooler pics!!
Looks like a lot of work done there, Looks good !, keep it up , A+ for home brew fabrication!
THE stage III wheel requires machine work on the turbine housing and is 56.90 MM for TO4E (TEE OH FOUR E) exducer Minor diameter exhaust wheel and just a little bigger exhaust discharge hole diameter in the turbine housing, about 2.25" I believe for stage III . I think stage III will have less exhaust back pressure than a smaller wheel, yes the smaller wheel will spool faster, but with a 2800 stall torque converter either one should spool lightning fast! THE stock T3 exhaust wheel has a 49.25MM exducer, and there is a 54MM exducer T3 wheel listed by garrett.
stock t3 exhaust wheel is 65.50MM inducer major diameter-- 49.25 MM minor exducer exhaust discharge outlet
largest t3 exhaust wheel 65.50MM inducer major------------54.00MM minor exducer, STAGE II ? This is the one Limit engineering put in my TA33C retrofit of stock T3 hotair turbo, IT cost me $750 about 5 years ago, do not know what one gets today to rework a stock hotair turbocharger into the TA33C?
TO4E exhaust wheel 72.90MM major inducer-----------56.90 MM minor exducer, back pressure is the enemy of turbo horspower, but you need enough to make the turbine run at all. THE hot air T3 exhaust housing is unique and has it's limitations on how much HP you can squeeze out of it. maybe 400+ hp, but not much more, the exhaust inlet is smaller than a barbie doll's you know what.
Best regards, TURBO E38