ToxicWS6

So right now i have a MP76 with 4in inlet, 2.5in outlet .72 AR compressor side and t4 divided 3.5in vband with 1.0 ar exhaust/turbine side, theres 2 turbos ive basically narrowed it down to and right now its a descion based on a 70mm or 76mm and what ar.

One question i had, or what confirmed, would a 76mm with a t4 .81 exhaust spool close to or equal to a 70mm t4 turbo with a .96 exhaust ar (i know compssor side and other things come into account but for a basic understanding of this concept above)

That being said the 2 turbos im looking at are...

Cold Side
Compressor Wheel 61mm
.70 a/r
4” Inlet and 2.5” Compressor Outlet
Inducer- 70mm
Exducer- 99mm

Exhaust Side
Exhaust Housing T-4 Flange
.81 or .96 ar Exhaust Housing
3.0″ Vband outlet
Inducer- 74.5mm
Exducer- 65mm

Or

Cold side
Compressor Wheel 76mm
.80 a/r
4” Inlet and 2.5” Compressor Outlet
Inducer- 76.71mm
Exducer- 102.36mm

Exhaust Side
Exhaust Housing T-4 Flange
.81 or .96 AR
3.0″ Vband outlet
Inducer- 74.5mm
Exducer- 65mm

Engine is an lq4 bored .020 with turbo cam and 317s, t56 tranny and 9inch with 3.70 gears, on 12psi with current turbo, hit full boost around 3200-3400rpms

Goal is 600-650rwhp, or whatever 12psi nets me assuming turbo dosnt run out of steam, quicker the spool the better cause this is more a DD/autocross/road course car, im leaning towards the 70mm with .81ar for spool time but idk if it will max out, that being said would the 70mm with .96 be better or 76mm with .81ar be better if the 70mm with .81 be a choke point

Thanks!

Ps this was typed on phone so sorry if it seems jumbly

JoeNova

Those both look like On3 turbos.

Get the largest A/R possible. Those turbine wheels are small and usually chock up on a 6.0, especially one with a cam.

ToxicWS6

They are on3 turbos, ue to pricing, figure i could experiment with a $300 turbo better then a $1k turbo lol.

Ur suggestion would be the 76mm or thr 70mm with the .96 then?