Water Pump and Thermostat

[epapp]

I agree with all of this, I think we were all saying the same, mostly correct things, just talking about different sides of the argument.

Now the thing I am curious about is: running oil at a cooler temp (to a point) is a good thing, no contest. But running the coolant COOLER than what the ECU is expecting as a 'warmed up' engine could also be bad. Fuel trims are different based on engine temperature, and the tstat being a 180 degree tstat is that way so that the M96 can run at the CORRECT heat based on its sensors and fuel map, metal composition, expansion factors, tolerances, etc...right?? Seems like running at a lower temp (to a point as well) could also be bad, in the best case, potentially just worse fuel economy?

[JFP in PA]

Originally Posted by epapp

I agree with all of this, I think we were all saying the same, mostly correct things, just talking about different sides of the argument.

Now the thing I am curious about is: running oil at a cooler temp (to a point) is a good thing, no contest. But running the coolant COOLER than what the ECU is expecting as a 'warmed up' engine could also be bad. Fuel trims are different based on engine temperature, and the tstat being a 180 degree tstat is that way so that the M96 can run at the CORRECT heat based on its sensors and fuel map, metal composition, expansion factors, tolerances, etc...right?? Seems like running at a lower temp (to a point as well) could also be bad, in the best case, potentially just worse fuel economy?

Has not proven to be the case with a 160F stat. The DME has the leeway to adjust the fuel trims from cold start (often very cold) to running in Death Valley conditions., as well as adjusting for pretty large changes in altitude. If the DME ever "ran out of rope", the car would start coding because the computer had reached its limits; I have never seen or even heard of that occurring with a low temperature thermostat. You need to also not that the "high output" Porsches (Turbos, GT cars) run 160F stats from the factory.

I've also not hear of anyone suffering decreased MPG as the result of using one of these units; and in fact have had customers comment that they feel they are seeing a small but reproducible increase in fuel mileage. I don't really know how real that is, but after several different customers commented on it, you have to take note of it.