With the Evo 8/9 throttle body it's pretty common to delete the coolant lines running to it in an attempt to keep intake air temps slightly cooler. Has anyone done this yet on the X? With the drive-by-wire throttle system I'm curious of the throttle plate motor needs coolant flowing through the system for cooling and/or lubrication.

 

I *thought* about it when I had my car apart but with the way the stock hoses are I decided to just put them back on the TB. On the evo8/9 you could cut one of the stock hoses short and it would fit perfect to circle back to the inlet/outlet. That trick didn't seem obvious on the X and I wasn't in the mood to mess around with it.

 

Not sure how removing the coolant lines is gonna keep it cooler.

Sure, you eliminate all that 200* coolant from going in, but at the same time you remove the best means of thermal egress from any heat on the intake charge.... external surface air cools a lot slower than internal water does.

 

The "coolant" lines are there not to cool but rather heat the housing in cold weather to abate ice formation. Put a wooden dowel in the input end and secure it in place with a hose calmp then re-attach.

 

200F coolant vs. near-ambient temp air...the coolant will heat the throttle body which will in turn slightly warm the intake air. Coolant is used to cool the engine and turbo (obviously), but used to heat the throttle body to prevent it from icing over in the cold.

 

the coolant lines are really only there for idle conditions. at WOT, the air is moving to fast to allow any (measurable) heat transfer from the millisecond it is in contact with the warm aluminum with no significant surface area for transfer.