=Overview=
Before air enters the throttle body it must first pass through a cast aluminum pipe which connects the intercooler exit hose to the throttle body. The problem occurs where this pipe meets up with the rubber connetion, there is a lip which poses a rather large restriction to the incoming air. This modification requires grinding and sanding to smooth out this transition to allow for smother airflow.
[[file:NG_900_Throttle_Body_Cast_Porting_1.jpg|thumbnail|none|Throttle Body Cast External]]
==Cost and Difficulty==
# I then wrapped the intercooler tubes, both the inlet (lower) tube and the outlet (upper) tube, with Thermo-Tec Thermo Shield high temperature reflective insulation (www.thermotec.com). A foil faced fiberglass duct or pipe insulation could also be used for this application. I cleaned the tubing first with lacquer thinner inside and out. Insulating the tubes will reduce the amount of heat the intake air absorbs from the turbocharger, exhaust manifold, and engine compartment. Insulating the intercooler tubes took about a 1-½ hours.
# You probably don’t want to use silicone grease on the rubber coupler or the ends of the intercooler tubing, as it might allow the tubing to slip out of the coupling when under pressure. If the fit is too tight, then a little soapy water on the ends of the intercooler tubes will help to slip them back into the rubber fittings. Be sure the tubing is properly seated and the clamps are tight, as the turbo pressure will be trying to blow the tubing out of the joints. If one does pop off, be very careful putting it back as the turbo and exhaust get very hot very quickly.
[[file:NG_900_Throttle_Body_Cast_Porting_2.gif|thumbnail|none|Throttle Body Cast Porting Before]]
[[file:NG_900_Throttle_Body_Cast_Porting_3.jpg|thumbnail|none|Throttle Body Cast Porting After ]]