throttle body selection

[FMuscle]

I was just looking at universal TB for my build, how should I choose the size of it?
My pod filter is 3 inches/75mm, from there I have about 10 inches to the S/C 2.5"/60mm inlet, in which space I have to fit the TB and a bypass pipe, then once blown the air goes through the 2.5"/63mm FMIC, then to the corolla inlet which has a 2"/51mm opening.

My stock/current TB is 46mm in diameter. Already a restriction to the 51mm inlet. But since it's not going in the stock location, a 50mm throttle body is out. But should I get a 60mm to match the S/C inlet, or a 75mm to match the pod?


My theory to have the TB at 60mm fixed to the S/C and engine, with a silicone reducer to the pod. But I could be wrong.


Here's a highly detailed 3D model of my future setup.

[5e colin]

i sugest to use same size tb as your piping intercooler piping is you could use the stock 4efte 1 at 50mm

i would keep pipes as small as possible without restricting

[FMuscle]

It's 2.5 from the S/C to the IC. I have a reducer after the IC to 2.0 to match the rolla inlet. I guess I'm going with a 60mm TB.
Even if there's a bit of variation (60-63mm) 2.5in seems alright.

I think I'll need to add poly mounts to reduce movement on such a short pipe... pod to s/c

[Stu]

60-65mm is a good size. Ive had a few 4e's through with 75+mm units and they often have decel to idle stall issues especially with custom inlets with small plenums (these have had aftermarket ecu's by the way). You can tune a decent size idle bypass solenoid to avoid the issue though but takes some time.