90mm throttlebody

[rag231]

Why is the 90mm throttle body the "benchmark" for stage 2 performance? This part is used on every single hp level of a stage 2 motor. The reason I am asking is my wife's LS motor has a FAST intake on it, we are waiting for the 102mm throttle body to get here to fire it up ( had an ls6 intake before) Has there been any experimenting going on to say, yep the 90mm is better than the 105mm. I have seen maybe 2 cars that have bigger. I am getting ready to get my intake worked on and will be in the throttle body market soon. I want one with the black anodized Wiggins clamp on it.

 

[Mike E]

Bigger might be better for flow, but there is a point of diminishing returns. The problem with a big throttle body is that there is very little low throttle angle resolution for street driving. 10% open on a 102mm throttle body is a whole lot more air then 10% on a 70mm.

Bigger is more of a benefit for an n/a motor where intake restriction hurts a lot. On a turbo motor, your blowing air through it an it's less of an issue. Chris Lyons went low 8's with a 70mm Buick style throttle body.

 

[Dusty Bradford]

The n/a car will benefit from a larger TB like the 102mm if it has some engine mods. It's trying to suck air vs our cars which are blowing through the TB. A 90mm will support well over 2500hp in a turbo combo so your not going to gain power on a Buick when going from a 90mm to anything larger. I still run a 90mm TB on my turbo big block.


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[Mike E]

I think 90mm kinda became the standard becuase a 4" tube is pretty much the same size, so no weird adapters are needed to hook up charge tubes. A 102 or 105 are going to take a weird sized silicone reducer. 70 and 75 work really well for 3" tube.

 

[rag231]

This info feeds into my cylinder head and intake theories as well, velocity and volume....hmmmm.

 

[karolko]

I think 90mm kinda became the standard becuase a 4" tube is pretty much the same size, so no weird adapters are needed to hook up charge tubes. A 102 or 105 are going to take a weird sized silicone reducer. 70 and 75 work really well for 3" tube.

FYI 90mm = 3.5"

 

[Mike E]

Yes, but the OD of the throttle body where the silicone coupler clamps on is 4".

 

[karolko]

mike are you running 4" tube? I am running 3.5" and it is tight around the turbo and charge pipe. a 4" would never fit...

 

[Mike E]

I'm using 3" and a 70mm ford style accufab throttlebody.