they aren't the same, but they are interchangable.

 

The NT is 4mm larger but it doesn't have the right structure to put on the throttle body elbow.

 

Not correct. The n/a throttle body is the same exact bore size as the turbo. It is 4mm bigger on the inlet, but necks down to 64mm i believe at the plate. I use one currently on my car, It is working excellent. the inlet inside diameter is almost perfect match for 2.5in piping, so it gives it a better transition. I purchased a 45 deg bend hose and it is working excellent. It is bigger and less dramatic of a bend than a 2g elbow. Hope that helps. Nate

 

You are correct, the NT T/B is 64mm, I was under the impression that the turbo one is 60mm.... I've heard bad stories that the NT T/B seals leak under boost. That might be causing my problems.

 

You can get new seals cheap, and they are very simple to install. Thats what i did right when i got my n/a tb. Nate

 

Thanks for the info. A buddy of mine has a couple of the n/a motors lying around. He said I can have the tb off one if I want it. I'm gonna go ahead and get one to try out I think.