Why is the Throttle Body Water Cooled?

[JSM]

Searched but didn't find anything?

 

What exactly does it cool and why? Is it necessary for turboing?

[cygnusx1]

I think Nissan water "heated" the throttle body to keep it from freezing open/closed in the winter. Mine is no longer "watered".

[spork]

Most people disconnect it eventually. My daily driver has it hooked up while the race car doesn't...of course, I'm not using a stock TB on the race car and I saw no reason to waste the time to install it.

[JSM]

So I'm assuming Orlando, FL driving it is unecessary?

[JSM]

You mean to tell that a mechanical device that opens and closes w/ sensore needs to be warmed? Sounds a little strange, but then again, i've always lived in the warm.

[slownrusty]

Strangely enough many company do not water cool the throttle body...BMW for instance.

 

Yasin

[jp 280]

Another way if thinking of it. Warming the throttle body with collant will in effect bring it up to say 90deg. Id think of this as also stabilising the intake temps, for a consitant power in any outside running conditions. Of corse none of us want that. I love cool outside temps

[zcarnut]

It's not to "cool" the throttle body, it's for heating it...

 

I asked an automotive engineer (he worked for Ford) this same question a few years ago and he said it is only done to reduce the carbon build up on the throttle blade. It had nothing to due with emissions or driveability. Apparently carbon is less likely to collect on a heated surface. Such deposits can result in throttle sticking and claims of “unintended accelerationâ€.

[alexideways]

Well, that is good to know I'll go to bed a bit smarter tonight, I am a mechanic and I allways tought that it was to prevent iceing like for a carb. setup.

 

Thanks.

[Tony D]

Yeah, in an EFI car with heavy PVC possibilities the hot area will slough off carbon and reduce throttle sticking.

On a carburetted vehicle it was solely due to the JT-Effect whereby air rapidly expanding at high velocity (cracked throttle plate to high vacuum) tends to chill to freezing temperatures. Thanks to some gasoline added to the mix, and it's vaporizing somewhat, it gets even colder. Any moisture in the airstream can condense at that point (at best), and in some cases stick to the intake or carburettor body where it had been supercooled byt the air and flash-freeze to make an ice buildup. This icebuildup can hold the plate open, with disasterous effects!

 

My VW Bus with a Zenith 32NDIX could make a HUGE ice-ball under the carb on humid days back in Michigan. I'm talking ice built up like at a cryogenic valve, sometimes over 1/4 thick. On the inside, who knows? But externaly it built up like crazy and caused drivability problems (another reason on CARBBED cars).

 

But on EFI vehicles it depends on where the PCV is admitted and managed. I'll lay money BMW's schematic for the PCV system doesn't allow a lot of contaminants into the intake system upstream of the throttle body like the Datsun did. Trace out a few cars, and you will find that is usually the case, PCV ducting will determine if the EFI T/B is heated or not. Unlike claims to the contrary, engines are engines, and engineering is similar no matter who builds it!

[johnc]

The TB is cooled because blipping the throttle can overheat the throttle plate...

[JSM]

So with all this banter back and forth do I use it or not?

[BRAAP]

If you are building a performance engine, then don’t use it. There is no need to HEAT the throttle valve above ambient air temp, (colder air into the engine means more power right?). If you live in Alaska or there abouts, then keep it.

 

The purpose of running 195 degree water across the throttle valve is to keep the intake air temp as consentient as possible, i.e. easier to keep a predetermined AFR for emissions reasons, (you did catch that I mentioned the word Emissions right?)

 

It is my NOT so humble opinion that to retain the water line going to the throttle valve is ONLY because you plan to routinely drive your sports car in a climate indicative to Alaska or northern Canada.

[Tony D]

The purpose of running 195 degree water across the throttle valve is to keep the intake air temp as consentient as possible, i.e. easier to keep a predetermined AFR for emissions reasons, (you did catch that I mentioned the word Emissions right?).

 

 

I would have to humbly disagree on that point. There is not enough surface area to do much of anything to the incoming air temperature due to the JT effect at partial throttle, and at WOT it doesn't stand a snowball's chance in hell of affecting temperatures. If it was that kind of setup, like on stationary engines, or F1 Honda engines, it would havea thermostatic velve tied to intake plenum temperature.

 

The true reason was as above, to keep carbon from heavy PCV sloughing off and pliable while driving, and to let it move into the floor of the plenum where accumulation can be tolerated instead of at the throttle plate.

 

Datalog with a standalone EMS system and you will see the effect on intake plenum temperatures are almost totally dependent on vehicle speed and underhood temperature. Disconnect or pinch off those lines and do the same test and you will see nil temperature changes. The wonderful world of Megasquirt opened my eyes on that 'warms the air" myth straightaway! It heats the metal, in both EFI and Carburetted Applications. In both cases it's to prevent a buildup of contaminants on the metal portion of the body to prevent throttle plate interference/binding/sticking.

[BRAAP]

I apologize. Tony is absolutely correct. In my readings about that water passage on EFI Throttle valves, I interpreted the water passage to be emissions related for temp consistency and as such I have always struggled with that theory for the same reasons Tony mentioned, i.e. there really isn’t squat for contact area for water to transfer its heat into the throttle valve to be effective in that capacity.

 

Any how, thanks for setting me straight on that.

[MrFancypants]

The TB warmer is a perfect dedicated parallel circuit in the engine cooling system for use in your custom turbo application

 

Otherwise, unless you plan on driving your baby in cold climates, there's no need for the TB warmer.

 

 

 

- Greg -

[JSM]

Thanks guys. That is what I thought, dont use it.

[naviathan]

Ummm, I don't think that was the intended point. So by not using it you'll allow cabon to build up on the throttle plate eventually leading to throttle sticking. Are you sure you don't want to use it? Is this a daily driver car? I would use it given the above statements.

[cygnusx1]

Carbon build up happens so slowly that the butterfly would wipe it away faster than it could accumulate. However, the areas that are not wiped by the throttle plate would thicken with carbon and eventually cause a poor idle and stalling. I can't imagine it would ever cause throttle plate sticking because the throttle plate constantly wipes its own path. Ice however, can build up really quickly if cruising down the highway at a steady throttle angle. This could cause a big surprise when it was time to slow down and the butterly was frozen in place. Planes have carb heat for ice prevention.

[wreckedj30]

Also if the car is a turbo, the turbo it self should heat up the throttle body, more than enough to disapate carbon build up. Correct or na.