Grn92LX said:Its fine, once you have good 'breathing' mods, match your TB to your inlet opening. An internet myth is that you need "lots of boost" or "a big stroker" or a "high rpm car", but the truth is that couldn't be anymore Wrong!!
the intake pipe is (will be soon) a 3" PVC pipe, i assume 3" is the inner diameter, but it may be the outer ... i'll check at lunch.eades5.0 said:What size is the opening when the TB mates up to the intake (or elbow)? I know most aftermarkets are 70mm, anything biggger is a waste...unless you port it.
that settles it, i'm going with a 75mm unit! now i just have to find one ...TMC said:I used the 75mm TB with stock E7 heads and the car ran well. I used that same TB when I had TF heads and the car still ran well. IMO you should use the larger TB’s and work other things to get what you want. The way I see it more restriction on either side of the engine is a bad idea. Open the intake and exhaust up (within reason) and you will have the ability to make more power.
When I raced NMRA Factory Stock we were limited to a 70mm TB but had we the option to us a 75mm unit I would have. That motor had unported Explorer heads and intake with a stock cam and I still feel that the larger TB would have been a benefit.
The idea that boosted engines need a larger TB is also kind of weird to me. Why does an engine that is being force fed air need a larger opening than an N/A engine that is depending on natural air pressure to push air into the motor? Without doubt you can make more power with a larger TB on force fed engines…but I feel that the same is true with N/A motors.
Black96VertGT said:that settles it, i'm going with a 75mm unit! now i just have to find one ...
i am 80 mm at the mass air, 76.2 mm (3" interior diameter PVC) at the intake pipe. i think a 75 mm throttle body matches.GTJake said:Jesse's right, if the elbow/upper plenum has only a 70mm opening then the 75mm WILL HURT YOU. If everthing matches then your fine.