I currently have a honda 62mm throttle body going to a victor x manifold. It is going to be used on a turbo'd car with 2.5" piping. Are the gains really that noticeable to spend $300-$450 on a bigger throttle body? My goals are 700whp. built 83mm gsr w/bw s366. Thanks H-T.

 

You should be able to get a larger TB for $100-$150.

 

I've always sized the TB to the intercooler piping. If the throttle body is smaller than the piping there is some airflow and power to be had by matching it or going slightly larger but really anything beyond the pipe size is overkill and typically will not flow any more air or make any more power than the rest of the inlet system can support. In your situation a 62mm throttle body would be a good match and should support as much air as the 2.5" pipe can flow aside from some minute flow losses associated with the throttle blade.

Bo

 

Eh I would get 3in piping on the cold side your goals are fairly high after all, and go as big as you can on the T/B for as few $$$ as possible.

 

If I upgrade to 3" piping I will definitely go to a bigger TB, because it would be like putting a restrictor in betweening the piping and the intake manifold. Would it make a difference to upgrade to bigger piping (3")?

 

fwiw, i too have a bored stock b16 throttlebody, with 2.5 piping and a a vic x. i made 710whp. 83mm gsr t3t67ho.

 

I made 800hp on my car yesterday, stock honda throttle body with a victor x manifold. I've made over 850hp on a stock honda throttle body in the past.. Would I see a decent gain with a larger throttle body? I doubt it, and I'd rather not be worrying about the screws falling out of the throttle plate on the aftermarket throttle bodies anyway..

 

I guess I will put my money on something that will give me more gains.