# Grand National Turbo



## OverTake (Feb 7, 2006)

What size is the grand national turbo, i have one and i know its a garrett, but i dont know what kind!


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## wes (Apr 30, 2002)

Probably a T3 with a .63 exhaust housing and a 60 trim compressor wheel. At least thats my best guess. Not all of the GN's had the same turbo AFAIK. I believe the GNX had a different turbo. If you want more details probably best to be researching this on a turbo Buick forum than here on NF.


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## OverTake (Feb 7, 2006)

Im need a T3 turbo for my manifold,


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## wes (Apr 30, 2002)

OverTake said:


> Im need a T3 turbo for my manifold,


HUH? The GN turbo is a T3. If you have the manifold and a turbo, do they not line up? MANY OEM turbo's use proprietary flanges....


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## Petrovich (May 13, 2005)

wes said:


> HUH? The GN turbo is a T3. If you have the manifold and a turbo, do they not line up? MANY OEM turbo's use proprietary flanges....


Yup. Actually, Buick Grand National turbocharger is a popular upgrade for high-power 931's, not least because it has a 3-bolt turbine inlet, just like my stock KKK unit. One thing it WILL do is it will bolt up to GA16 and maybe SR20 stock non-turbo manifold (causes clearance issues, though). However, it's not compatible to Nissan 4-bolt turbo flanges.


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## OverTake (Feb 7, 2006)

wes said:


> Probably a T3 with a .63 exhaust housing and a 60 trim compressor wheel. At least thats my best guess. Not all of the GN's had the same turbo AFAIK. I believe the GNX had a different turbo. If you want more details probably best to be researching this on a turbo Buick forum than here on NF.



O if it is im good to go. Im wasent sure, expecially when you said ''Probably''. Thanks Guys


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## wes (Apr 30, 2002)

OverTake said:


> O if it is im good to go. Im wasent sure, expecially when you said ''Probably''. Thanks Guys


Like I said you need to check. It sounds as if the GNs use a 3 bolt flange. If they do then it will not bolt on to your regular 4 bolt T3 flange. I am not sure why this is so hard though. Regular T3 series turbo's are a dime a dozen.


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## OverTake (Feb 7, 2006)

The Gn turbo has a 4 bolt flange, And yes it mounted on the t3 manifold. Your opinion wes, Is the Gn T3 turbo a good ideal to use for the ga16de motor?


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## wes (Apr 30, 2002)

OverTake said:


> The Gn turbo has a 4 bolt flange, And yes it mounted on the t3 manifold. Your opinion wes, Is the Gn T3 turbo a good ideal to use for the ga16de motor?


Ideal, no. Will it work, yes.


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## OverTake (Feb 7, 2006)

Why dont you think the gn turbo is not a gool choice for the ga?


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## wes (Apr 30, 2002)

OverTake said:


> Why dont you think the gn turbo is not a gool choice for the ga?


Arrgh, well I believe it is an OK choice. There are better choices that have already been proven to work very well. These options pretty much range to all budgets, so if those work the best, why would you not use one of them? If your going to re-invent the wheel just do it and see how it works out.


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## pimpride (Mar 28, 2005)

Isn't the T3 rather big for the GA16?


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## OverTake (Feb 7, 2006)

Yeah, your right, I did a little research, so im sticking with the tdo4


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