Hey i wasnt sure where to post this, so ill through it in here. My friend was telling me about the removal of a coolant line that actually runs to the throttle body. Im guessung that it keeps the throttle body warm on a cold engine. Probably some sort of emissions thing. Anyways, he said removing it was good some extra power and it makes sense. So has anyone else heard of this. Any input? Well let me know thanks alot guys...............

 

I think your buddy is pulling your leg.

 

I have heard of this on a Silerado Pick-Up. I think that the purpose of this is to help out with fuel milage. Although I don't think that the 4G63 has the coolent ran through the throttle body.

 

we have coolant lines through both throttle bodies (on the SVX) and yes, removing them will pick up a couple hp by cooling the intake a couple degrees. It is a minor mod, kinda like grounding kits and high quality oils. Not necessary, but is another little bit of performance you can get out of an engine

 

can anybody post a "how to"

 

This is a common WRX/STi mod... go to NASIOC and you
ll find it...

 

TB Bypass How- To:

Materials: Brass Male to Male connector, zipties

Find the lines under or around your TB that hold fluid (SVX are under the middle of thr TBs) Disconnect the inlet and return. Simply use brass connector to loop the fluid, zip tie tubing. Close hood, don't try this if you live above Virginia-Kentucky line as the TB will stick in freezing weather.

 

Very easy mod. I live in the cold midwest and have had the mod for over two years with no problems. The thinking behind the design is to warm the throttle body faster in cold climates and "to keep throttle plate from becoming frozen." Obviously a lot of Evo owners live in warm winter areas and in general, winter is a season (a couple of months) so the modification is making car more effecient while keeping more of the coolent circulating in the engine. As far as HP- neglidgable at best.

 

This modification disables the FIAV (Fast Idle Air Valve) present in the throttle body. When the throttle body is cold a "plug" shrinks down opening up extra air passages in the throttle body alowing more air into the intake manifold for a fast idle on cold start up. As the coolant warms up the "plug" expands due to the heat blocking off the extra air passages so that your idle drops back down to normal.

The regular idle air valve can compensate some if you bypass the coolant lines, but you may need to make "seasonal" changes in your BISS (Bass Idle Set Screw) rather than having cold weather automaticly compensated for by the FIAV.

Keith