Water circulation through throttle body??

[1albagtp]

Hello I am sorting out a 92 that has had quite a few hands in it apparently.

While replacing all the coolant hoses I realized that the water through the lower side of the throttle body had been eliminated/ bypassed. Is there any other reason than related to cold weather running that water is circulated through the throttle body???
Thanks for your help, Bryan.

 

[Daedalus]

It has less to do with weather and more to do with proper engine running temps. The coolant helps to regulate idle speed by closing the fast idle valve. When the engine is cold the valve remains open to allow more air in, which raises RPMs and gets the engine warmed up quicker. When the coolant is sufficiently warm, it melts the wax in the FIV, which closes the valve. Bypassing the throttle body will cause the engine to idle high for longer than it needs to. Probably not harmful, but wasteful.

 

[MANIACura]

Some folks believe that bypassing the coolant away from the throttle body will lower the intake temperature and thus increase the horsepower of your car. This is probably what the previous owner was trying to accomplish.

 

[Larry Bastanza]

Some folks believe that bypassing the coolant away from the throttle body will lower the intake temperature and thus increase the horsepower of your car. This is probably what the previous owner was trying to accomplish.

I think this is theroetical, and more likely on FI setups. The idea is to prewarm the intake air. It is in the service manual. "The throttle valve is heated" is the comment.

JMO, no real facts here

Regards,
LarryB

 

[RON98]

done this before.

no issues.

 

[KooLaid]

I've read it helps to keep the carb from icing over in cold climates, lol carb. Well you know what I mean. I don't plan on messing with it in my car, but I was gonna remove it from my scooter

 

[LJSB]

I've read it helps to keep the carb from icing over in cold climates, lol carb. Well you know what I mean. I don't plan on messing with it in my car, but I was gonna remove it from my scooter

Freeze? What is going to freeze? :biggrin:

 

[KooLaid]

In California, nothing :biggrin: Well unless you live in mountainous parts but hardly anyone lives there lol.

 

[Daedalus]

The rough math would suggest any temp change of the incoming air from the coolant in the throttle body is really negligible. I did a rough calc, and I assumed the entire throttle body was kept at a constant 180*F. At 7000RPM this worked out to a temp change of .6*F. In reality only a much smaller area of the throttle body would be found to be anywhere near coolant temp. Under FI, in which the mass flow of air is greater than NA, the temp change is even less. I'm sure the intake chamber, which has more surface area and which is heated via conduction and convection from the heads, would have a larger impact on intake temps.

 

[Tanto2]

Got to be the lone disenter here. Any self respecting performance engine builder would not leave this on if HP was the prime directive. The it's too small to bother with sounds like a Pelosi comment. Of course the slow warmup is probably enough reason for 99% of street folks to keep it. I am a minimalist fanatic FWIW. If I don't need it, it gets removed, especially if it makes power, even a hundredth of a HP. FWIW same goes for the cooler thermostats when tuning with an aftermarket ECU. Cooler thermostats make quite a bit of real HP on pushrod V8's.

 

[1albagtp]

Thank you all for your comments. I assumed it was similar to the water routed adjacent to the crankcase vent pipe, again in order to allow positive operation in cold ambient temperature running. Thanks again for the input, Bryan.

 

[nsxotic911]

...The it's too small to bother with sounds like a Pelosi comment. ....QUOTE]

Nice