Just wondered if the 3800 */C engine has a heated throttle body, as the K engine does. Doing some thinking.

Description of the 2000 SC engine'* throttle body.

The throttle body uses a throttle plate to control the amount of air delivered to the engine. The TP sensor, the MAF sensor, and the Idle Air Control (IAC) valve are also mounted on the throttle body.

Vacuum ports located behind the throttle plate provide the vacuum signals needed by various components. The engine coolant is directed through a coolant cavity in the throttle body in order to warm the throttle valve and prevent icing.

So...yes.

whatcha thinkin' about?

Whether heating the throttle body is necessary at all.

Got a used LIM from Mark (Vital49) today and was checking it out. A few years ago Ron 350 mentioned to me by PM that one way to stop UIM failure would be simply to thread and pipe plug the coolant passage holes in the LIM, thus cutting off coolant to the UIM and throttle body.

I've got a sleeved UIM in my car, but I noted when swapping it out that the throttle body is only a few inches above an exhaust pipe loop and the EGR tubing.

See where I'm going with this?


Hmmm.

ahhhh very interesting...
definately like to see where you go with this

A few people drilled and tapped the LIM on CGP. I'd say since your in Cali you con't have to worry about warming up the TB.

Bob you sure you want to do something that drastic?


The owner of this L36 has no complaints although he needs a reduced stovepipe.

Ron, almost certainly not. But I got the spare LIM, was giving it a look, and was thinking it over.

I'm doing some redesign work on my sleeved UIMs, and will use Bill Buttermore'* reduced diameter stovepipes as part of the kit. I got some thinner wall stainless tubing, now .805 ID versus .775, so the air gap is now .090 or so.

We've been lucky enough not to have any sleeved UIM failures yet, but the increased air gap sure isn't going to hurt anything.

The biggest problem I have right now is UIM cores. I gotta solve that somehow.

Hey, what did you do to that LIM, weld it up and machine it down, or is that epoxy?

If you look at my latest engine bay pic at http://bc.atcx.com/cotm/2006/03/s_performance.jpg , you'll see I have little temp strips all over? I have 8 on the top end now. Trying to see if the coolant flow actually helps COOL the SC and TB at higher boost levels after long hot runs. The coolant obviously heats it after starting, particularly with a drilled thermostat, but what is the net effect when the SC is creating heat itself?

I'm figuring out all aspects of your question as we speak. I will not be using a 'permanent' method of plugging the holes in the lIM if I go that way. I'll be plugging it with either a threaded plug that can be removed later or with a freeze-plug type device. But first, I have to know what high-rpm, high boost run does in the heat of summer.

In attending a car meet. There was a Regal with a TB spacer/block off plate. In talking with the guy, he mentioned it helps greatly because of not having the heated coolant pass through it.

I would look more toward blocking off the LIM than I would the TB. If you block off the TB...the UIM still has pressure and coolant in it to fill the UIM if failure occurs.