Hi to all !! can a 3rd gen RX7 throttle body be used on the 20b UIM ? I know the bores are the same size 1x45 2x50 mm but does it bolt up?
Thanks

 

as far as i know it does, because i've seen people put 20b throttle bodies on 2 rotors before.

 

it does bolt up

 

It will bolt up but you will loose the IACV (idle air control valve). 20b TB has the IACV on the tb itself while the IACV is on the 3rd gens UIM.

 

There is also a slight difference in the bottom design of the 3rd gen TB and the 20B UIM and you'll need to get a gasket cut to prevent a leak. I have this combo (FD TB and 20 UIM) and found out about the difference and leak when I pressure tested the system. It was leaking like crazy and the prior shop that worked on the car had tried to use silicone to fix the design difference. Bad idea as chunks of it were coming out. The new shop cut a gasket to fit and no problems since then.

 

You also lose one set of butterflies with the FD TB.
The stock 20b elbow won't fit it however (2 studs on the bottom vs. 1), you'll have to resort to the FD Greddy elbow (or custom elbow), which is a good idea in the first place as it makes it easier to match up IC piping, and you can find them cheap used.

 

thank you very much for the responce to my question ,it's all clear now I will pick up the 3rd gen throttle body and make a gasket for it.