Forced Induction Superchargers | Turbochargers | Intercoolers

Using 2 stock GN turbos...

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Old Sep 30, 2005 | 08:19 AM
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Default Using 2 stock GN turbos...

I have a 5.3 and am contemplating a twin turbo setup down the road using stock manifolds flipped over. The stock GN turbos are cheap as hell and I was just wondering if you think I'll be able to get 600 fwhp with two of them. I think they each can support 350 hp apiece, so I thought this might be possible. I was thinking about swapping out the heads to lower the comp. ratio. Do you think ~ 9.0 would be good?

Also, what do guys do when they have twins and run a large single intercooler? seems like it might be a problem since one side's piping will be longer than the other's. Should I run twin intercoolers?

thanks
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Old Sep 30, 2005 | 01:33 PM
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btw GN = Grand National turbo v6 turbos, i.e. twin T04B's.
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Old Oct 1, 2005 | 07:50 PM
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nobody?
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Old Oct 1, 2005 | 11:27 PM
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why would you run them into a y when you can just run them to each side of the intercooler. they make intercoolers that run into each side and discharge out the top. as far as 600 I'm not sure
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Old Oct 2, 2005 | 01:50 AM
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check turbomustangs.com. alot of people there run them. even though its mustangs, you can still get a idea on what to expect.
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Old Oct 2, 2005 | 12:08 PM
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Originally Posted by red90cobra
why would you run them into a y when you can just run them to each side of the intercooler. they make intercoolers that run into each side and discharge out the top. as far as 600 I'm not sure
ok, I wasn't sure that they made intercoolers like that.
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Old Oct 3, 2005 | 07:49 PM
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3500lb Buick GN's can go low 12's on the stock turbo with 20-22psi and high timing. That is around 400hp.

You can typically find them for $150-225 used in good working condition ready to install.

See the link in my sig for how fast I went with a stock turbo in a 2810lbs (with driver) GN powered RX-7. I dynoed at 330rwhp/360rwtq with an unlocked torque convertor running 91 octane/alchy and only 19psi with 2.5" downpipe. With 21psi (was having wastegate issues) I imagine it would've made 350-360rwhp unlocked.

.63 A/R on the turbine would yield instant spool. 750-800flywheel hp would probably be the limits.... with twin setup. The stock style wastegate with a larger WG puck will control boost sufficiently.

Last edited by gnx7; Oct 3, 2005 at 08:00 PM.
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Old Oct 3, 2005 | 07:49 PM
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The GN turbos can be used for low HP applications. The A/R and flange size aren't the best suited for a larger V8 engine.

Jose
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Old Oct 3, 2005 | 09:11 PM
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Originally Posted by JZ 97 SS 1500
The GN turbos can be used for low HP applications. The A/R and flange size aren't the best suited for a larger V8 engine.

Jose
Even with twins?
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Old Oct 3, 2005 | 09:13 PM
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Yeah even with twins. But you aren't looking for mega hp as well.

Jose
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Old Oct 3, 2005 | 09:16 PM
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Originally Posted by gnx7
3500lb Buick GN's can go low 12's on the stock turbo with 20-22psi and high timing. That is around 400hp.

You can typically find them for $150-225 used in good working condition ready to install.

See the link in my sig for how fast I went with a stock turbo in a 2810lbs (with driver) GN powered RX-7. I dynoed at 330rwhp/360rwtq with an unlocked torque convertor running 91 octane/alchy and only 19psi with 2.5" downpipe. With 21psi (was having wastegate issues) I imagine it would've made 350-360rwhp unlocked.

.63 A/R on the turbine would yield instant spool. 750-800flywheel hp would probably be the limits.... with twin setup. The stock style wastegate with a larger WG puck will control boost sufficiently.
I can get the turbos for insanely cheap, and can weld my own hot parts and charge tubes so this could end up being a very cheap setup...relatively speaking.

What exactly are the stock 86-87 GN turbos? T04B's with what a/r inlet and outlet? I can't seem to find this info. So do they have internal wastegates? Do you think I would be ok going with dual GN intercoolers too?

thanks
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Old Oct 3, 2005 | 09:19 PM
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Originally Posted by JZ 97 SS 1500
Yeah even with twins. But you aren't looking for mega hp as well.

Jose
Yeah I dont think I'd want more than 550-600 fwhp. This is going in a 2600 lb Rx7.
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Old Oct 3, 2005 | 09:27 PM
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Ahh very nice power to weight. That thing should be stupid fast......
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