408 with tc78 #'s??
408 with tc78 #'s?? Before i get flamed for not getting a bigger turbo this is a full street car and I want instant boost. And its what I have and out of money soo. Motor is a tsp 408 with a 9.5cr, car is in the shop getting motor and a new turbo setup put on. Just curious if anyone has used such a small turbo on a bigger cubed ls motor and if so what kind of #'s did it make? Car has a performabuilt lvl3 with a vig3200 and fueling this thing will be no problem. Also running stock casting 317's with upgraded springs etc and custom turbo cam.
TECH Enthusiast
Joined: Jan 2004
Posts: 608
Likes: 0
From: New Zealand
If its a rear mount turbo setup should be ok.
If a front mount get the biggest AR exhaust housing you can.
I have one on a 383 front mount, with a .96 ar housing it choked badly at the top end, power would fall over from 5000 rpm
Have since gone to a 1.32 ar housing and it pulls much better at the top end (haven't had it back on dyno yet though)
If a front mount get the biggest AR exhaust housing you can.
I have one on a 383 front mount, with a .96 ar housing it choked badly at the top end, power would fall over from 5000 rpm
Have since gone to a 1.32 ar housing and it pulls much better at the top end (haven't had it back on dyno yet though)
just an update. As told the car makes really good power up to 5800rpms then falls on its face like I hit the brakes. Turbo is mounted under the hood and I had no room to go any bigger. My only option is to get a smaller motor and I already had the motor so it will stay for now.
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Verdad Gallardo TECH Enthusiast
Joined: Jan 2004
Posts: 608
Likes: 0
From: New Zealand
what ar exhaust housing did you end up going with ?
I have just built a bigger manifold for the turbo side and gone to a 3 1/2" downpipe, which has helped top end and spools even faster.
I thought the turbo was done at 17 psi , could crank the boost controller up and not make any more boost.
Decided to fit a bigger intercooler gone from 24x12x3" to 4" has improved cooling heeps and picked up 3psi at the manifold.
will get it back on the dyno soon and see where its at.
You would def make more power with a bigger turbo, but the TC78 is great for a 90% street driven M6 car, spools super quick, no lag between shifts and makes enough power to break traction at 100+mph in 4th gear !!
I have just built a bigger manifold for the turbo side and gone to a 3 1/2" downpipe, which has helped top end and spools even faster.
I thought the turbo was done at 17 psi , could crank the boost controller up and not make any more boost.
Decided to fit a bigger intercooler gone from 24x12x3" to 4" has improved cooling heeps and picked up 3psi at the manifold.
will get it back on the dyno soon and see where its at.
You would def make more power with a bigger turbo, but the TC78 is great for a 90% street driven M6 car, spools super quick, no lag between shifts and makes enough power to break traction at 100+mph in 4th gear !!
If its a rear mount turbo setup should be ok.
If a front mount get the biggest AR exhaust housing you can.
I have one on a 383 front mount, with a .96 ar housing it choked badly at the top end, power would fall over from 5000 rpm
Have since gone to a 1.32 ar housing and it pulls much better at the top end (haven't had it back on dyno yet though)
If a front mount get the biggest AR exhaust housing you can.
I have one on a 383 front mount, with a .96 ar housing it choked badly at the top end, power would fall over from 5000 rpm
Have since gone to a 1.32 ar housing and it pulls much better at the top end (haven't had it back on dyno yet though)
the problem you going to have is the TC series of turbos already have a smaller 60 series compressor housing. So compared to other 76's or 78's your already at a disadvantage.
Way too small. I'm running a tc78 and a 402. Car makes good power but I have over 40 psi exhaust back pressure. The exhaust pushes the wastage opened at 15 psi boost. And I'm running 25 psi of spring. U need a t6 sized turbo 88 mm and up for a 400+" motor.
how much power at 15psi?
well I just ordered a precision custom 78mm billet turbo with a 80mm compressor wheel and a 84mm turbine wheel. ar stayed a .96 tho. I might have to change my down pipe to an oval shaped pipe to fit 3.75 for better flow after the turbo but ould make waymore power and spool up like a ****.
Last edited by jonathan8751; Nov 3, 2010 at 10:07 PM.
