Help Me Understand Thermostats

chromebumpers

solid fixture here in the forum
Staff member
What difference does it make if you install a 180 degree thermostat or a 190 degree if the car always reaches normal operating temperature of 200 in a short time running?

Riddle me that one Batman!
 
It will open up sooner for wintertime heat but its really not going to make a whole lot of difference
 
Hotroders include lower temperature T stats in their so called “Performance” stage 1 Packages. One of my son’s friends showed me something he bought for his mid 1990’s LT/1 Camaro. It was a throttle body air horn piece, a 180 T stat, fuel regulator and a K & N type air filter. This kit advertised a hp gain of 15 to 20 hp “Horsepower you can feel by the seat of your pants!” on the box. :p Sure!
 
What difference does it make if you install a 180 degree thermostat or a 190 degree if the car always reaches normal operating temperature of 200 in a short time running?
The cooling system is not adequate if it reaches a temperature above the thermostat's rated
temp. It's the thermostat that should determine the operating temp.
 
That’s where I get lost. A 180 degree T Stat just opens at 180, the water temp can still rise above that and frankly most often does.
 
It's no different than the thermostat in your house. If you set it at 72°F, but the house continues
to rise until it gets to 80°F, then you can make an argument that the system is not of sufficient size.

The higher temp thermostats are an effort to improve efficiency, although it's going to be small. It
also probably has an effect on emissions.
 
the heat transfer rate and the efficiency your engine runs at is determined BOTH by the efficiency of the vehicles cooling system and the t-stat opening temp
the t-stat is limiting flow below its rated temp, the cooling system efficiency, the rate the cooling system can transfer heat to the outside air flow, the outside air temp,
will determine the upper or running temp above the t-stat opening temp.
keep in mind a t-stat does not limit the cooler coolant entering the engine, its function is to keep the coolant flow through the engine minimized,
until its absorbed enough heat to reach the t-stats opening temp that allows the coolant to flow out of the engine.
coolantflow.jpg

radcool1.jpg

it might help if you think of it this way,
if you had the cars water pump inlet hose connected to a swimming pool,
and the engines output hose dumping back into the far side of that swimming pool
the engines coolant would enter the engine at (ROOM TEMP) and the t-stat would open once the pool water in the engine reached its temp setting, it would pick up heat as it traversed the engines coolant passages but with an unlimited volume of pool water at near room temp as a supply the t-stat would constantly open and close, and coolant temps your sensor showed would rarely exceed about 10 degrees more than the t-stat, even if the t-stat was a 160f or a 200 f, rated t-stat, unfortunately, all cooling systems don,t have a (unlimited ability to supply room temp coolant) so the temp runs at what ever temp the cooling system can operate, remember the outside air flow might be anywhere from -30f-110f in various areas of the usa, but thats always a considerably lower temp than the engines coolant so the radiator can transfer heat to the outside air flow. obviously the greater the difference in temp between the coolant exiting the engine and the outside air flow temp, naturally once the car/trucks up to cruising speed ,that ADDS TO THE AIR FLOW RATE THROUGH THE RADIATOR OVER WHAT THE FANS Alone can supply in air flow rates, remember the larger the surface area of the radiator ,and the higher the rate of air flow over the radiator surface, the more efficient the heat transfer can potentially be!

reading the links should help

http://garage.grumpysperformance.com/index.php?threads/thoughts-on-cooling.149/



http://garage.grumpysperformance.com/index.php?threads/how-the-cooling-system-works-basics.853/

http://garage.grumpysperformance.co...ing-system-flow-rates-and-heat-transfer.9880/

http://garage.grumpysperformance.com/index.php?threads/tips-on-cooling.199/
 
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If for example your t-stat opens att 180F, and the cooling fan starts at 200F (not unusual) the engine will operate att 200F when driving slow (and when testing emissions...) and run at 180F highway.
I have also seen temperature (and oil pressure) gauges on "modern" cars that shows steady "normal" but the real temp varies a lot, like 160-200F, i guess its made so to make car owners feel calm :)
 
Hey, I actually learned some things I never associated together. Have to search Craigs L now. A couple of those links were great, thank you!
 
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