I don't think my GTA had a thermostat when I bought it. Will this adversely effect the computer/drivability?

 

This is a very bad thing. The car will never be able to warn up when driving. You will never be able to get into closed loop operation.

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1989 Iroc-Z 5.7 350, Blue, T-Tops

Lightly Moded:
Edelbrock Headers, Rebuilt B&M 700R-4 Tranny, Higher Stall Torque Converter, Airfoil, K&N's, Ported Plenum
-- Blue LED Bakelite Dash & Climate Control
"Just some 17 Year old spending every dollar I make on my car."

 

i've heard all kinds of things. from over cooling to overheating. with no thermostat a car will warm up. it will take forever tho. and i have heard from a more reliable source that it will overheat. the thermostat is a restriction in the coolant flow. it can't flow thru the radiator too fast. if it does, it won't have the time to cool off in the radiator, and be put into the engine still hot. this would cause an overheating problem. i don't know for sure what it would do, but it is not right. i would put a 180degree stat in and forget about it


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86 IROC
43,000 miles
305/700R4/3.23 gears
maroon, gold stickers, black interior, T-Tops.

current mods.
shift kit
headers
cat back exhaust

mods planned for this winter
cam
3.73 gears
subframe connecters

 

it will just run cooler. wont hurt anything, just take longer to warm up. alot of drag racers use this as a trick to keep their engine cooler at the track. your engine will still eventually heat up.

 

I agree with UR about it just runnning cooler. The agrument that it will overheat is non-sense. It defies all laws of physics.

Whether it is okay to run without one or not really depends on the ambient air temperature. With very high ambient air temperatures, the car would most likely attain closed loope (around 115*F), but if the temperature was say under 80*F, there is a very good chance that the engine will attain a coolant temperature less than 115*F causing the engine to go into open loop. Also, the TC (if you have an automatic) may cease to lock-up. On SD cars, it is a separate paramater, but it too is set around the same temp as closed loop.

What is most likely to happen in hot air temps, is the engine will attain closed loop but will much cooler than even 160*F. This will cause the ECM to think it is in "start up" mode and cause you to run too rich, thus needlessly burning gas and possibly hurting performance.

 

So what's a good thermostat to put in that won't make it run too hot but will still make it run properly through a nice cold NY winter and hot summer?

 

Someone called Pat Goss with this question last weekend. He said the only problem would be that the engine would run much cooler and you would have oil sludge build up since the contaminants wouldn't be burned off.

 

1ve heard the stock chip tells the computer that the car is warm at 160, so ive heard the best temp is somewhere between 170-180.

i bought a 180 for my camaro, now i just gotta drop the engine in.

jon

 

Yeah, all the dealerships in the area say it will run rich w/o a 'stat. So I spent the 4 bucks and got a 180 for the Trans Am, I'll put it in tonite.

 

Does anyone have a good arguement as to why the car would not overheat without a thermostat? I am inclined to think that it would.

Is the amount of heat being transferred to the coolant from the internal cooling passages of the engine block per unit of time is (hopefully) less than the total heat dissapation capacity of a copper/brass radiator cooling fins while standing still? No it is not. This is why we use fans to increase the amount of air flowing across the radiator cooling fins.

There is also a maximum quantity of air that will flow through the radiator at any speed, a speed which, I'm guessing is relatively low maybe 35 mph. That is to say, the radiator has a fixed maximum cooling capacity. A vehicle travelling at this speed, with an engine with no thermostat producing less heat than the total cooling capacity of the radiator, will cool the engine down to ambient temperature as time approache infinity. The converse is also true. A car producing greater then the radiator's cooling capacity travelling for an infinite amount of time will approach an infinite temperature.

So how is this controlled. On the bottom of the spectrum we use a thermostat to modulate the engine temperature. On the upper part of the spectrum we use the concept of turbulent flow.

Turbulent flow is created by adding restriction to the coolant passages. Did you ever wonder why nobody polishes up their coolant passages? The creation of turbulent flow relies heavily upon the concept that energy is an instantaneous quantity that can only be transfered as a function of time. The more time coolant spends in the coolant passages, the more energy it can absorb. But in the radiator, the surfaces are smooth. Because the transfer of energy must occur over a period of time, a stream of hot water moving at an infinite rate of speed through a radiator will not cool down. As the speed of coolant through a radiator approaches zero, the coolant temperature approaches ambient temperatures. But we can't stop coolant flow all together, or the engine would overheat. Enter the thermostat. A modulated restriction to coolant flow. Back me up here.

 

just to add some noise to this conversation...

when i bought my GTA, temperature was steady 160 when i was driving. i thought it's the thermostat, but the the truth is, the thermostat was stucked open.

my guess is, if you're driving around without thermostat it will hurt just your wallet by increased gas comsumption since engine/ECM wont reach the normal operating temperature.


-P

 

yeah ive got a good arguement to why it wouldnt overheat if there was no thermostat. mainly because the coolant passes through the block and heads first before it ever has a chance to run back to the radiator. mainly that and my car doesnt have a thermostat in it since last week when i was at the track. it just takes a little longer to warm up. never sees above 180 in stop and go traffic. that and the coolant is under pressure constantly because of the water pump assures you that the water going through the block and heads first will absorb heat then move back to the radiator removing heat, then it starts over and goes back into the block after the coolant has already passed through the radiator and has been cooled.

 

The restriction of the coolant passages in the engine should have no real bearing on the flow rate of the coolant passing through the engine. The thermostat serves one purpose, to open/close-restrict/free the flow of coolant throught the engine/cooling system. What that means/does is when the engine is cold,like after start up, the thermostat is closed to inhibit the flow of coolant in the system, and stop the cooling of the engine, thus not adversely affecting heating up capabilities of an internal combustion engine. With out a thermostat you are intentionally cooling and already cold engine. With an open(or missing) thermostat as the RPM's rise you are spinning the water pump faster thus sending coolant though the system at a faster rate. A thermostat decides if you are going to move your coolant at all. RPM's decide how fast your are goin to push it. Thermostat's work on a bi-metalic spring theory. As temperature rises one side of the spring shinks thus creating movement(a choke works the same way). So yes flow of coolant is regulated by a thermostat, but not the rate of flow, so lose this passage restriction nonsense.