Does anyone know of a 180 thermostat for a ls3 that ACTUALY RUNS AT 175 TO 180 OR SO ??? i have tried 3 murry 174 and they all run at 190 to 198.
I tried checking in hot water they start to open at 188 if i maintain 185 in the pot the thermo is open less than 1/16 or closed depending on the thermo
Why? That engine SHOULDN'T run at 180. It should run at 200 degrees. They run better hotter. They're designed to run that hot, actually hotter than that. It's better for them. They make more power at 200 than they do at 180.
This is one of the biggest misconceptions about the LS engine. They are NOT 1st gen small block iron headed engines. They are not designed to run at lower temps. It is actually counterproductive.
Furthermore, the temp of the stat does not determine where the engine runs temperature wise. The stat temp is just the temp when it opens. The overall cooling system and your fan settings will determine what temp it runs at. Rarely will any engine run so cool that the stat is what ends up controlling it. You'd have to have a ridiculous cooling system for that to happen. The only way it should run at the temp stat of 180 is in cooler or cold weather on the highway with a bunch of air pulling the heat out.
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typically + 12fOriginally Posted by SDCE
A 180 thermostat will not run 180 degrees. I'd expect 192ish
A 160 will run around 180.. sometimes as low as 177.
Usually the best dyno pulls are between 190-200F.
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This. Thermostat rated temp is the temp they start to open not the temp they maintain.
An engine's thermostat is not like the thermostat in your house, you can't just set it to whatever arbitrary temperature you want. The car's engine (which produces heat), radiator (which removes heat), and thermostat (which controls the time the coolant allowed to spend in the radiator removing heat) all share a very complex thermodynamic relationship.
Bottom line, if you want the engine to run cooler, you need two things:
- a cooler thermostat
- and a radiator that is capable of shedding the excess BTU's
If you want to test something, remove the thermostat completely and report back if the ECT is lower or higher than before. By your logic if you remove the thermostat the coolant should run at what temperature? Ambient air temp? It won't.
But also...LS engines like the heat. So why are you wanting to run it cooler in the first place?
A standard approach will give you standard results.
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A very real, real world example just a couple months ago. A buddy of mine just finished his filled iron block turbo methanol drag radial car/engine. The only coolant is in the heads. The "radiator" is an off the shelf transmission cooler. we put it on the dyno and I figured we'd need to start the pulls around 150. Just warm enough to get a little heat in everything. Starting the pulls that low seemed like something was wrong with the engine. It audibly sounded like it was laboring. We were on the dyno all day so we did a couple tests where we'd do a 150 ECT pull then follow it up again with a hotlap. The difference in 150 start temp and 190+ start temp was literally 100 hp. Even with a purpose built race engine, the difference in the way it ran from 15-160ish to 200ish was staggering to say the least.
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Current-day F1 engines run damn near 300*F coolant temp, if not more... for lots of reasons, but mostly because they want to run the smallest radiators possible with the least amount of airflow through them, and the greater the difference between coolant temp and ambient temp the easier a given radiator can dump heat into the air.
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thank you for all your responses. I ran this engine on my engine dyno for a few weeks and i learned that its favorite temp was 180 ect with 200 degree oil temp . I do most of my dyno pulls at 300 rpm per sec which makes for a long test . not to add the confusion on coolant temp but another reason i do not want to run 200 temps is because at 200 there hot spots in the heads of over 230 240 which is fine for a factory t5 355 aluminum casting . however i am using t6 356 aluminum with thin seat rings .t6 356 starts to aneal around the exhaust seats above 230 then the seat moves and looses the valve seal.with a 174 stat the radiator stays cold till 194 . with the factory gm stat the radiator got coolant at 198.
I do agree that cold engines in general do not make good power .
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