The S14 SR20DET's came with a 50mm throttle body. The Silvia SR20DE's on the other hand, had 60mm throttle bodies - just like the S13 SR20DET or SR20DE. To retain the cold start hardware of the S14, you can't put an S13 throttle body on the motor. (the S14's cold start is integrated into the throttle body) This swap will increase the size of the S14's throttle body by 20%.

Here is a comparitive shot of the NA on the left, and turbo on the right.

Here you can see the Automatic Transmission type throttle position sensor (TPS) with two connectors. The label on it says H7 (Heisei 7, or 1995) Then S14 and AT for auto tranny. We decided not to mess around with the auto TPS, and just swap on the manual tranny TPS we had handy from the old throttle body. However, the auto TPS should work fine, as many have said.

Before removing your throttle body, you should check the TPS voltage at idle while its connected to the car. This way, when you reinstall it, your voltage will be exactly the same and not require adjusting.

While you have the throttle body off the engine, this is a perfect opportunity to clean out your intake manifold as much as possible. We sprayed a lot of B12 Chemtool in there to get off all the carbon within sight. We also cleaned the throttle body before installing it, as it was filthy, too.

Here is a pic of the back side of the TPS. This tab must ride against the spinning part that comes out of the side of the throttle body.

When you put the TPS on, you will have to place it and then twist it to apply pressure on the TPS from the throttle plate opening. Be sure to test it and look for pressure there before bolting it all down to the car. (its a lot more difficult to work with once its on)

Connect it to the engine harness and turn the key on. Adjust the TPS until the desired voltage at idle is hit. Then check full throttle to make sure its working like it was on the old throttle body.

Now you're ready to bolt the throttle body back on there. Make sure the gasket is still intact and there are no leaks anywhere. Double check your vacuum lines to be sure.

Driving impression - Very responsive, more power on hand at any given time. No dyno sheets yet to prove the actual gain, but its faster for sure.