Not ls related please read description
Thread Starter
Teching In
Joined: Dec 2025
Posts: 2
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Not ls related please read description Hello everybody, I’m not new to forums but new to this one and I know I should be posting in the commodore forum but most people on that forum aren’t the best at giving the good feedback so yeah hopefully you people can help me out with honest genuine feedback, currently own a 1999 holden commodore with a n/a 9.4 comp 3.8l l36 engine and need some advice from the wise men and women on here. Now I’m planning my first ever turbo build with twin rear mount t3t4 hybrid turbos with a potential rev range of 3000/3500 to a 6500rpm limiter
specs for the turbos \/
COLD SIDE
gt35 61/82 billet comp wheels
gt35 .70 a/r 4” inlet 2.5” outlet
HOTSIDE… now this is where I’m stuck in choosing what turbine wheels I should keep as a set & forget for a broad hp range from low (stock motor) 400whp to high (built motor) 700whp
Standard turbine wheels
Turbine Inducer: 64.8mm
Turbine Exducer: 55.8mm
or
stage 3 turbine wheels
Inducer diameter: 65.0mm
Exducer diameter: 56.59mm
Turbine housings .63 or .82? what ever I end keeping will be t3 3” vband outlet turbine housings
motor will have stock cam with 1.98 rockers (custom) with 130# valve spring, stock heads or mildly ported heads (budget dependent) and stock or mildly ported intake manifold (budget dependent) with 3” y pipe to ether 3” or 3 1/2” single exhaust to the back bumper
what do you guys think?
specs for the turbos \/
COLD SIDE
gt35 61/82 billet comp wheels
gt35 .70 a/r 4” inlet 2.5” outlet
HOTSIDE… now this is where I’m stuck in choosing what turbine wheels I should keep as a set & forget for a broad hp range from low (stock motor) 400whp to high (built motor) 700whp
Standard turbine wheels
Turbine Inducer: 64.8mm
Turbine Exducer: 55.8mm
or
stage 3 turbine wheels
Inducer diameter: 65.0mm
Exducer diameter: 56.59mm
Turbine housings .63 or .82? what ever I end keeping will be t3 3” vband outlet turbine housings
motor will have stock cam with 1.98 rockers (custom) with 130# valve spring, stock heads or mildly ported heads (budget dependent) and stock or mildly ported intake manifold (budget dependent) with 3” y pipe to ether 3” or 3 1/2” single exhaust to the back bumper
what do you guys think?
Last edited by 3.8v6man; Jan 1, 2026 at 12:08 AM.
Thread Starter
Teching In
Joined: Dec 2025
Posts: 2
Likes: 0
It’s not gonna be right at the back of the car as it’s gonna be a metre after the front subframe right after the transmission oil pan of my 4l60e so I guess I should have initially said it’s mid mounted, I’m planning on using the .63 housing where the standard wheel, reckon that’ll work better with my rpm range or still too far?
Last edited by 3.8v6man; Jan 2, 2026 at 12:24 AM.
That 4l60e isn’t gonna live longer than a few dyno pulls at 700whp lol. I agree those are way too big and won’t spool at all even with the smaller housing. Why not a single or a blower?
