I just replaced a 20 year old waterpump...

[blue62]

Originally Posted by pilut2

Ok- so you don't want to do the research.... I'm not an expert, but those who are explain that the stock thermostat starts opening at about 186 F and is fully open by 210 F- whereas the low temp version starts opening at 160 F and is fully open by about 185 F. This results in lower operating temperatures- oil and coolant- for more most driving conditions.

I have done research, lots of it over the years.
It is why I am surprised that so many people are going to a thermostat that is outside the manufactures system operating parameters.
When you run cooler then the system is set up for it takes longer to go into closed loop.
You run on cold startup fuel map longer.
harder on the Cats. hard on o2 sensors
Running at lower temp takes longer for the oil to reach its operating temp. (which is typically very close to 195)
Resulting in oil being bypassed at the bypass valve for a longer period of time.
Takes longer for the oil to reach a temp where it burns off water.
For every pound of fuel burned (that's about half a quart) a pound of water is produced. Not all of it goes out the tail pipe.
Some of it ends up in the oil.
Just a few things that result from running cooler then spec.
Now if it is a race car or a car you track I get it.
If it is a street car?????

So that is why I was curious as to why it seems that lots of people are going to the cooler thermostat.

[Ciao]

Originally Posted by blue62

I have done research, lots of it over the years.
It is why I am surprised that so many people are going to a thermostat that is outside the manufactures system operating parameters.
When you run cooler then the system is set up for it takes longer to go into closed loop.
You run on cold startup fuel map longer.
harder on the Cats. hard on o2 sensors
Running at lower temp takes longer for the oil to reach its operating temp. (which is typically very close to 195)
Resulting in oil being bypassed at the bypass valve for a longer period of time.
Takes longer for the oil to reach a temp where it burns off water.
For every pound of fuel burned (that's about half a quart) a pound of water is produced. Not all of it goes out the tail pipe.
Some of it ends up in the oil.
Just a few things that result from running cooler then spec.
Now if it is a race car or a car you track I get it.
If it is a street car?????

So that is why I was curious as to why it seems that lots of people are going to the cooler thermostat.

Makes sense; factory specd water pump has and continues to be my choice.

[JFP in PA]

Originally Posted by blue62

I have done research, lots of it over the years.
It is why I am surprised that so many people are going to a thermostat that is outside the manufactures system operating parameters.
When you run cooler then the system is set up for it takes longer to go into closed loop.
You run on cold startup fuel map longer.
harder on the Cats. hard on o2 sensors
Running at lower temp takes longer for the oil to reach its operating temp. (which is typically very close to 195)
Resulting in oil being bypassed at the bypass valve for a longer period of time.
Takes longer for the oil to reach a temp where it burns off water.
For every pound of fuel burned (that's about half a quart) a pound of water is produced. Not all of it goes out the tail pipe.
Some of it ends up in the oil.
Just a few things that result from running cooler then spec.
Now if it is a race car or a car you track I get it.
If it is a street car?????

So that is why I was curious as to why it seems that lots of people are going to the cooler thermostat.

Simple: It is better for the oil, and for the engine. In spite of your research, the only reason the factory run these cars so hot was emissions, period. Back when LN first introduced a 160F thermostat, we collected data on UOA's in cars before and after installing the thermostat. Net result was that nearly all of the oil values (film strength, TBN, viscosity, water content, fuel content) were excellent for longer run times on the car running the cooler thermostat. We saw absolutely NO increase in either fuel of water contamination in oil samples, and oil quality was much better for many more miles. We have also seen no change in O2 sensor life or performance, or in cat life expectancy. And contrary to your data, oil temps in these engines are typically much hotter than 195F when running the OEM stat; 225-235 is more like it.

As for fluid warm up, your data is also suspect. How fast an M96 heats up is a function of the engine's specific heat out put rate at any given ambient temperature; the thermostat functions just like the one in your home: Regardless of where it is set, how fast the temperature rises is constant, only the point at where the thermostat takes control and throttles the system changes. Fully instrumented M96's warm up both the oil and coolant at the same rates, regardless of which thermostat is in play. Only their final "steady state" temperature changes.

You might also be interested in the fact that every turbo, GT2, and GT3 car left the factory with a 160F stat in them...…….

[blue62]

Originally Posted by JFP in PA

Simple: It is better for the oil, and for the engine. In spite of your research, the only reason the factory run these cars so hot was emissions, period. Back when LN first introduced a 160F thermostat, we collected data on UOA's in cars before and after installing the thermostat. Net result was that nearly all of the oil values (film strength, TBN, viscosity, water content, fuel content) were excellent for longer run times on the car running the cooler thermostat. We saw absolutely NO increase in either fuel of water contamination in oil samples, and oil quality was much better for many more miles. We have also seen no change in O2 sensor life or performance, or in cat life expectancy. And contrary to your data, oil temps in these engines are typically much hotter than 195F when running the OEM stat; 225-235 is more like it.

As for fluid warm up, your data is also suspect. How fast an M96 heats up is a function of the engine's specific heat out put rate at any given ambient temperature; the thermostat functions just like the one in your home: Regardless of where it is set, how fast the temperature rises is constant, only the point at where the thermostat takes control and throttles the system changes. Fully instrumented M96's warm up both the oil and coolant at the same rates, regardless of which thermostat is in play. Only their final "steady state" temperature changes.

You might also be interested in the fact that every turbo, GT2, and GT3 car left the factory with a 160F stat in them...…….

JFP
Glad to see you jumped in on this.
Yes it seems all car manufactures number one concern is emissions everything else being secondary.
The primary reason modern day cars run hotter then pre smog days.

Interesting data you collected.
Good information to be considered.
Always trying to broaden my knowledge base.
I wonder if your findings are relatable to most modern day cars???
That would be interesting information

[Starter986]

Thank you, Jeff.

You saved me some quid, and peace of mind. Coffee on me next time you're in SoCal.

Or a cocktail. You can choose your poison.