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What degree thermostat runs best?

 
Old 06-13-2019, 10:36 AM
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Default What degree thermostat runs best?

I just received an email from Mezeire enterprises in regards to the included thermostat that comes pre-installed with the pump.
It's a Staton 13008 180 degree.
Mezeire confirmed with me that my Tridon high flow thermostat will not be compatible with this pump.
The pump uses the traditional GM / Chevrolet thermostat found in SBC and BBC engines from the '70s and '80s.
My only other option is to use one of mezeires other thermostats and I have my eye on a 160 degree thermostat.

https://www.meziere.com/Products/Coo...60-degree.aspx

What do you think I should do?
Use the one that comes with the pump or purchase the 160 degree version?
Personally I prefer, the 160 degree so engine runs cooler but I want to see your views before I make any decision.
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Old 06-13-2019, 10:42 AM
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The cooling and operating tempature is dictated by cooling capacity and flow, not by the actual thermostat. A 160 will open sooner, but if you don't have the required cooling capacity or airflow, the engine will still overheat.
Personally, I would leave the 180 in to get the coolant and motor up to operating temps sooner....that's what I'm doing with my EWP I have on my LS7.
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Old 06-13-2019, 10:46 AM
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Originally Posted by fnbadaz06 View Post
The cooling and operating tempature is dictated by cooling capacity and flow, not by the actual thermostat. A 160 will open sooner, but if you don't have the required cooling capacity or airflow, the engine will still overheat.
Personally, I would leave the 180 in to get the coolant and motor up to operating temps sooner....that's what I'm doing with my EWP I have on my LS7.
I have really good hardware.
A high flow radiator that costed me 1000 USD because it was custom made.I can't remember if it was a 5 or 6 row.
Top of the line.
I just like the engine running cool that's all.
I had a 160 degree in there before I had overheating issues and I liked how cool the engine used to run with it.
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Old 06-13-2019, 11:34 AM
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A 180 degree vs 160 degree vs a hypothetical 120 degree thermostat all have the same thing in common:

The actual temperature is controlled by how good your cooling system is.

If your cooling system is actually good enough to maintain 160F, then yes, it will start cooling and keep it at 160 F.
If your cooling system is only good enough to maintain 210F, then the 160F thermostat will just open it earlier, but you'll still have the same end result.

Obviously, you understand this. But, now the question is... lets say the thermostat you use is 180F, and your cooling system is good enough to maintain a solid 180F, how much colder do you really want to run your engine?

An engine running too cold will have issues, too. I believe 180F is an amazing temperature to run at. I feel like 160F is actually too cold, given that your cooling system can actually keep it right at 160F. The oil temperatures need to climb in order for proper fluid dynamics/characteristics of the oil itself.

Thanks,
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Old 06-13-2019, 01:48 PM
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An LS thermostat opens at 176* if itís a 160* because it is on the supply side not the return side.

Is the Meziere EWP like the LS, or is it on the return side like a SBC?

If it is like a normal LS I am also a fan of the 160 (176* opening)
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Old 06-13-2019, 02:51 PM
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Operating temperatures have been a great debate for years..... So lets look at it this way. Why does GM run these cars at 200-220 degrees? They wear less there? The engines heat allow it to swell to deliver the acceptable tolerance. When you run your motor cooler/tighter you are going to wear parts quicker. How hot does nascar run their motors lap after lap? Is it because they can only control it but so much or is there power and longevity there? Just food for thought
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Old 06-13-2019, 02:59 PM
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Originally Posted by lazerlemonta View Post
Operating temperatures have been a great debate for years..... So lets look at it this way. Why does GM run these cars at 200-220 degrees? They wear less there? The engines heat allow it to swell to deliver the acceptable tolerance. When you run your motor cooler/tighter you are going to wear parts quicker. How hot does nascar run their motors lap after lap? Is it because they can only control it but so much or is there power and longevity there? Just food for thought
Exactly... and I strongly agree. It's not like it costs GM "more" to put a lower temp thermostat - there's a reason GM likes their engines running between 190 to 225. Heck, a stock c7 thermostat is what, 190F? They're trying to get away with the highest possible temperature for fluidity, before obvious engine life reduction - this temperature range is what they believe results in the greatest balance of engine longevity, and performance.
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Old 06-13-2019, 03:20 PM
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I like my 180* stat the best and ive had 160, 180 & stock. 160 is to cool imo especially in cold weather. Ive tried running my car at the track as cool as possible and warmed up all the way, it always goes quicker up to temp, 180-190*.
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Old 06-13-2019, 03:23 PM
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Originally Posted by lazerlemonta View Post
Operating temperatures have been a great debate for years..... So lets look at it this way. Why does GM run these cars at 200-220 degrees? They wear less there? The engines heat allow it to swell to deliver the acceptable tolerance. When you run your motor cooler/tighter you are going to wear parts quicker. How hot does nascar run their motors lap after lap? Is it because they can only control it but so much or is there power and longevity there? Just food for thought
Nascar runs their engines hot because they can minimize airflow through the radiator, improve downforce and reduce drag.

Aero guys want a sealed front end. Engine guys want full flow to the radiator.

I run my engines cold because I only have access to 91 octane. I do it for combustion stability. They do get hotter when I beat on them. I prefer to start whatever it is I'm doing at a lower temperature and if I'm beating on it the car will definitely come up to temp.

Last edited by spanks13; 06-13-2019 at 03:30 PM.
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Old 06-13-2019, 03:30 PM
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The key rationale behind a higher ECT is engine efficiency and emissions. Yes, component wear and performance are considerations as well - but the biggest factor is efficiency. Higher coolant temp means a smaller difference in temp between cylinder (during combustion) and the water jacket - which means less heat transfer from combustion to coolant - which means better thermal efficiency and better emissions. This improves fuel economy and reduces how much precious metals must be put into the catalyst in order to meet emissions regulations.

There are arguments to be made that all things equal (aside from coolant temp), that an engine operating @ 200F will experience less wear than the same engine @ 160F, but it depends a lot on the component tolerances.

You'll always make a handful more power running cooler, because the air will be heated less by engine components, and will therefore be more dense.

When I did engine development work on the dyno, when we wanted to post the absolute highest power number we could without "cheating" (pressurizing the test cell a little, or putting the exhaust suckers really close to the header collectors, etc etc), we would get the oil temp up to 250-260, and pull the coolant temp down to 150-160. This was always worth some power.
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Old 06-13-2019, 04:35 PM
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Originally Posted by Hodgdon Extreme View Post
The key rationale behind a higher ECT is engine efficiency and emissions. Yes, component wear and performance are considerations as well - but the biggest factor is efficiency. Higher coolant temp means a smaller difference in temp between cylinder (during combustion) and the water jacket - which means less heat transfer from combustion to coolant - which means better thermal efficiency and better emissions. This improves fuel economy and reduces how much precious metals must be put into the catalyst in order to meet emissions regulations.

There are arguments to be made that all things equal (aside from coolant temp), that an engine operating @ 200F will experience less wear than the same engine @ 160F, but it depends a lot on the component tolerances.

You'll always make a handful more power running cooler, because the air will be heated less by engine components, and will therefore be more dense.

When I did engine development work on the dyno, when we wanted to post the absolute highest power number we could without "cheating" (pressurizing the test cell a little, or putting the exhaust suckers really close to the header collectors, etc etc), we would get the oil temp up to 250-260, and pull the coolant temp down to 150-160. This was always worth some power.
This. Always appreciate your posts HE. You bring a lot to the discussions on Tech.
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Old 06-13-2019, 11:05 PM
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Great responses here.
However I am still thinking of going the 160 due to my high compression which produces more heat.
I was running a 160 degree thermostat for for 10 years on my my engine without an issue.
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Old 06-14-2019, 07:45 AM
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Originally Posted by bortous View Post
Great responses here.
However I am still thinking of going the 160 due to my high compression which produces more heat.
I was running a 160 degree thermostat for for 10 years on my my engine without an issue.
FYI - I'm 13:1 and will still run a 180.
You're running an aluminum block LS, correct ?
Plastic intake too ?
What do your oil temps look like ?

As noted above, the low temp thermostats like the 160* do not define the final running ECT......... unless you're running in freezing or sub-zero conditions
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Old 06-14-2019, 08:07 AM
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Originally Posted by fnbadaz06 View Post
FYI - I'm 13:1 and will still run a 180.
You're running an aluminum block LS, correct ?
Plastic intake too ?
What do your oil temps look like ?

As noted above, the low temp thermostats like the 160* do not define the final running ECT......... unless you're running in freezing or sub-zero conditions
I'm running 12:8.1 compression NA and my block is aluminium.
My intake is a fast 102mm
I don't have an oil temperature gauge but I am also fitting a 20 row oil cooler kit from improved racing along with a 185 degree oil thermostat to ensure oil temps are consistent and at the correct temperature.
I know the lower temps don't define ECT however, when I was running a cooler thermostat previously the engine temps were really good, especially on the highway.
It would stay at the 1/4 mark.
It stop and start traffic it would go between the 1/4-1/2 temperature line.
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Old 06-14-2019, 10:52 AM
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NASCAR engines have cooling systems that can withstand much higher pressures than road cars to bring the boiling point of water to over 300 degrees. During qualifying they basically seal the grille shut and after a few laps they'll pit to hook up external coolers that push ice water through the cooling system before the next round of qualifying. So they run their engines that hot to get better aerodynamics/downforce

My car runs well with a 160 tstat in it. Coolant temps when moving are between 180-195, I have the fans set so they come on full when temps reach 210+, and my oil gets up to temp just fine unless ambient is in the teens or lower. When it's that cold it takes a little longer to bring oil temps up but it's nothing crazy. I noticed it after watching the gauge for a few days in a row with different ambient temps

Last edited by xc_SS/RS; 06-14-2019 at 10:59 AM.
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Old 06-14-2019, 11:06 AM
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Cool bananas
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Old 06-14-2019, 01:57 PM
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Originally Posted by xc_SS/RS View Post
NASCAR engines have cooling systems that can withstand much higher pressures than road cars to bring the boiling point of water to over 300 degrees. During qualifying they basically seal the grille shut and after a few laps they'll pit to hook up external coolers that push ice water through the cooling system before the next round of qualifying. So they run their engines that hot to get better aerodynamics/downforce

My car runs well with a 160 tstat in it. Coolant temps when moving are between 180-195, I have the fans set so they come on full when temps reach 210+, and my oil gets up to temp just fine unless ambient is in the teens or lower. When it's that cold it takes a little longer to bring oil temps up but it's nothing crazy. I noticed it after watching the gauge for a few days in a row with different ambient temps
If your coolant temps are above 180 the 160 is just staying open and doing nothing once up to temperature. You could put a 180 and have identical results.
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Old 06-14-2019, 02:10 PM
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Higher coolant temps mean less heat going into the cooling system. I know that seems backwards but heat flows based on temp differential. Hotter coolant means lower heat flux. Means hotter chamber and post combustion temps

Likely GM picked operating temp based on fuel economy and emissions
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Old 06-14-2019, 04:37 PM
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From a thermodynamics point of view, there is a law that states, ...the higher the difference in temperature between a "heat engine" and its surrounding temperature, the more efficient the engine. In the case of a thermal combustion engine, we have limitations that include most notably, engine oil which begins to break down at some point. To summarize, as long as the oil is not thermally stressed and the rotating components are happy, the higher the temperature the better.

This is not an easy concept to explain/grasp, but as a student in a thermodynamics class in college, we were required to prove this theory. Maybe there are a few other mechanical engineers here who remember this tragic experience...

In the case of an automobile engine, many more factors contribute to the conversation. My comments are meant to add to the mix, not dispute other claims.

Another important factor mentioned earlier is that higher temperatures help remove water vapor and unwanted combustion by-products that affect emissions and efficiency.
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Old 06-14-2019, 08:22 PM
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Yup. You said it the hard way. If you really want to get into it peak efficiency is highest combustion temp with lowest exhaust temps. Basic Carnot cycle maths.

Higher coolant temps raises combustion temps. Knocking is the increased risk
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