# 85mm throttle body



## Papa Rad (Apr 30, 2012)

Looking at ordering DNA 80MM Throttle Body Pontiac GTO 4.6L 98-02 99 00 01 I have never messed with a throttle body before, only putting on the intake. From the sounds of it it would a be pretty much direct swap but what all is involved for that?


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## svede1212 (Nov 1, 2005)

That has to be a Chinese unit. A 4.6L GTO? I'd prefer a BBK 85mm going that route. They pretty much bolt on although tuning would be needed to be done for idle and such. They use an adapter plate to neck the 80mm or whatever down to the 75mm manifold opening so the benefit is muted. It is possible to grind out the neck of the manifold to about 80mm to get more. You'd gain about the same amount dumping the Flowmasters.


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## jpalamar (Jul 22, 2008)

I'd save your money. Without a matching intake, TB, and intake mani I don't see what you could possibly game from just a TB other then maybe some throttle response.


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## Papa Rad (Apr 30, 2012)

The reason for posting that one was the price. I'm defiantly finding more BBK being the way to go instead of buying a cheapo. I know the gain from it would be minimal without other mods (which will get done eventually) but I had a guy wanting my stock one so I figured i'd look into just getting it done now.


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## svede1212 (Nov 1, 2005)

What i did when I had a BBK 80mm was take the mainifold off (really easy unbolt), bolt the adapter plate onto the manifold and then took a die grinder with a stone and carefully ground the adapter and manifold neck out at the same time. I stopped frequently and checked my work. You can take the neck out to 80mm without grinding into the manifold TB O ring groove. 5mm increase to the size 75mm size is significant. 

I tune my own car. Changing TBs significantly changed my idle tune so be prepared for that. I had a BBK 80mm and also a Nick Williams 102mm. Getting and learning the basics of a tuning suite not only increases enjoyment of the car but gives real benefit whenever you change a part or diagnose a problem.


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