devins

I was curious if anyone knows about that coolant line that runs to the throttle body spacer and back down to the manifold. I've seen in some mags where it's disconnected. Seems like a good idea to not have hot coolant heating the intake charge. I know it's probably an emissions thing but can it be temporarily (until the next smog check...) removed?

91GT5.0

Yeah, but it doesn't do much of anything.

jeep45238

Actually (Chevy V8's have the same thing), it's to keep the butterfly valve from freezing shut in cold weather.



LS1's and LT1's have gained anywhere from 8-15 horses from bypassing it....

91GT5.0

I didn't notice anything by the SOTP dyno, but it coulda added some

devins

Somebody had told me that by disconnecting that line you run the risk of overheating the EGR portion of the throttle body. Does the coolant help keep that temp down or is the EGR completely separate? I've seen an EGR bypass plate available but not sure if that's necessary to remove the coolant line. My car is real sensitive to intake temp w/running 10lbs boost. The power difference from initial warm up to heat soaked is huge. Thanks for any help you can give me.

91GT5.0

I don't know, I've heard it helps keep the temp down, but I've also heard that it heats up the passing air for the ACT so the car gets better gas mileage. I really don't know what it's for.

lloydchristmas

Disconnect it and tie the two hoses together with a piece of brake line.

jeep45238

UH......dude, hotter air=BAD



Less O2 per unit of volume in the air.

91GT5.0

<blockquote>Quote: Originally posted by jeep45238 on 03 April 2003<hr>
UH......dude, hotter air=BAD



Less O2 per unit of volume in the air.



<hr></blockquote>



But that also keeps your gas mileage down. The ACT measures the air temp coming into the intake, and the computer reacts by adjusting the A/F ratio. Ever wonder why the car runs so rich while it warms up? Has to reach a certain temp before the comp goes into closed loop.

Less O2 per unit of air means that not as much gas needs to be added to get a stoichmetric A/F ratio, which helps gas mileage.

But like I said before, I don't really know what the coolant thru the EGR spacer is for.

jeep45238

Dude, that's not the reason the car runs so rich when it's warming up. The computer adjusts it to be rich when it's starting up to help kill detonation. On my car, well, actually, all Saturns, run rich as hell. How's 11:1 @ WOT sound<img border="0" src= smileys/smiley7.gif> ?



BUT, here's da thing. Once it's fired up and has been running for a couple seconds, engines generally lean out so they warm up faster. Lean=hot=engine warms up faster.



Besides......we're talkin about power here. Who cares about gas milage, especially when you're driving a 302 (face it, if you really cared you woulda bought a metro).