I currently have 3" piping before and after the intercooler. I'm getting a new throttle body that's 90mm with 4" inlet. My question is this. Is there any value in increasing my charge tube from the intercooler to the throttle body from 3" to 4" to match the TB opening? The car is not a drag car, and I value throttle response over the peak power. but if throttle response will not suffer by going to 4"... would love to hear your experiences/thoughts on pros/cons. thanks!

 

well put it this way, did you guys notice any power increase when switching to rotary works 90mm throttle body with the same intake charge tube? what's the point of just making the TB bigger and leaving the charge tube alone?

 

I was toying with a 90mm throttle body in the future maybe. Interested to see what you find. I would think if it is only a short length of pipe it shouldn't make much difference. I am working around a lag issue currently on my own car and wonder if my intercooler pipe run is causing it as it has a longer than usual route. I am only using 3" pipe though.
On a side note are you running a microtech ecu? All up and running. If so could you check my "AFR at idle" post and see if you can offer some graph screenshots to check mine against and get me in the right direction.
Thank you
Lee

 

Under the same conditions, your not gonna make more power just by installing a larger TB. You will however, will have to watch out for excessive throttle tip in with larger mechanical TB's (meaning more air enters the plenum at lower angles unless you set it up for progressive opening). Also the fast tip in effects the map sensor as the pressure differencial from vacuum to atmosphere will change more rapidly. For a street 20b, I wouldn't waste my time going that big unless your going big and matching the whole setup for max power (semi PP).

 

car made tons of power on regular TB and 2.75" piping, you may pick up a little high end