The throttle body on my 302 has a passage for coolant to pass through it. To me, this seems like a dumb idea...but then again I am not an engineer.

Why does the TB have coolant passing through it?

 

so it doesn't ice up.

many manufacturers do this.

 

Hes right.

Older carburators would freeze up, as dumb as it sounds.

By passing coolant through it, it keeps it from freezeing, then condensateing and haveing water get in the engine.

 

in california i usually disconnect it.

in ohio i leave it hooked up.

some say you can feel an improvement in power in the summer but i did not.

 

The coolant acts as a radiator to heat the air as it passes through the Throttle body due to the air mixture is "more efficent" its all art of the emissions BS.
Or so I was told.

 

This "freezing up" thing does not make sence to me. I had a old carburated rig that would freeze up on me. When I would go to start up, I had to hold the motor at or above roughly 1500rpm untill the motor was at operating temp, in which case I could let off the throttle and bring the motor down to an idle and go about my driving. If I were to let off the throttle too soon, the motor would die. Meaning, that the "freezing up" thing was a problem only when the enging is cold. The coolant flows through the throttle body once the t-stat opens up. That means that coolant only flows through the TB once operating temp is acheived.

Freezing up is a problem before operating temp is met.

Coolant starts to flow through the TB after operating temp is met.

Something isn't adding up or there is something that I am missing.

 

You have never driven a carburated car through a snow storm I see. The coolant flows through the TB spacer at all times, and prevents freezing of the throttle blades in winter conditions. At HWY speeds in extreme cold or when it's snowing is a partcular problem, there's just enough heat in the intake to melt snow, but it doesn't vaporize it builds up as ice.
I had the dubious pleasure of riding in an old Chev that had an aftermarket intake on it with a small filter on top of the carb and no heat riser. After about 30 minutes driving through snow we tried to stop but couldn't.. the throttle was stuck. We killed the motor and pulled over and quickly discovered the throttle frozen partially open. The carb throat and whole outside surface of the carb was coated in ice.

 

How come my 4.9L intake doesn't need a coolant passage around it??
My 87 Stang 302 had it, but my 92 F150 doesn't.

 

From the 1992 Ford Shop Manual in the 4.9L section.

The throttle body assembly controls airflow to the engine through a double butterfly-type valve. The throttle position is controlled by multiple-link, progressive opening, throttle linkage. The body is a single-piece die casting made of aluminum. It has a dual bore with an air bypass channel around the throttle plate. This bypass channel controls both cold and warm engine idle control as regulated by an air bypass valve assembly mounted directly to the throttle body. The valve assembly is an electro-mechanical device controlled by the EEC-IV computer. It incorporates a linear actuator which positions a variable area metering valve. Engine coolant is diverted through the throttle body mounting pad to improve cold weather operation.

 

also they usethe EGR systome to worm the air.

 

what does make sense? buying a hundai?

part of the reason is for feezing up, part is for emissions.

the government frowns upon bringing the engine to 1500 until warm.

the ozone is not too happy either.

if it really bothers you disconnect it.

 

This is an interesting question --why does Ford heat the throttle body on these V8s--but doesnt on their other non pushrod fuel injected engines? My 4.6 doesnt have this heated throttle body--nor does my 4.0 Jeeps. I can't remember any other vehicle with a coolant heated throttlebody.

I wonder if the relatively large area of a these dual throttlebodies dont have something to do with the necessity of heating the incoming air. But increasing the area of the throttlebody would slow the speed of the air and lessen the chances of icing--wouldnt it?? (I also thought that the area of these truck's throttlebody were larger than usual on these size engines displacements and RPM range--and the only reason for these large throttlebodies are to offset the restriction of the extremely long intake tubes.)

Why would Ford go to the expense of ducting cold air from the cold outside of the truck and then heat it as it passes thur the throttlebody?? If it was to prevent icing of the throttlebody--why isn't this heated throttlebody on all EFI vehicles?? I suspect that it is a "bandaid" type of engineering--to increase driveability/ control emissions--somewhat like the 25 pound weight placed in the front fender of Mustang convertibles to dampen vibration and resonance.

These manufacturers are not above using "bandaid" engineering to correct problems. A classical case of such engineering was back in 1975--Honda had problems with their CB360 motorcycles destroying cam lobs when idling on the sidestand. Honda's "bandaid" engineering was to lengthen the sidestand--so the bike would be more upright when on the sidestand--and save the lobs of the camshifts!! Unfortunately--the bikes started falling over in the wind with these longer sidestands--but that wasn't an warranty issue!!

 

chevy 305/350 engines in corvette and camaro with tuned port injection has them.

 

i

But it isnt the norm on EFI engines--is it?---and Chevy may not be above "bandaid" engineering.

I remember many cabureted Computer controlled engines back in the eighties--had coolant heated caburetors. But that most or many anyport injected engines dont have coolant heated throttlebodies. And if icing was the reason for the heating of TB--why dont all engines have their TB heated?? Just like all have outside air intakes??

 

i am not an expert on coolant heated t-bodies.

maybe if you do a search on google you can find the answer.