Quote:
Originally Posted by JFP in PA
Can't agree to eithier point.
We have run 160F stats on fully insrumented cars and consistenly found both lower coolant and more importantly oil temperatures when operating at steady state (cruise speeds). Coolant temps typically drop from around 205-210 to the mid to high 170F range. Oil temps drop 20-25F. Used oil analysis on cars befor and after adding the low temp stat showed the oil was in better condition after equivlant usage.
We have had multiple cars in the shop that had metal impeller pump failures that resulted in significant damage to the engine cases behind the pump. Several of these cars showed coolant circulation issues after being fitted because the new pump lost efficency due to the increased gap behind the impeller. Trimming impeller blades is a method to slow pump circulation rates, which is an old racers trick to improve high engine RPM cooling as usually the pump is moving coolant too much coolant under those conditions. But like everything else, there is a "too much" limit in doing this, when the reduced flow leads to over heating, particularly at lower engine RPM levels.
There are reasons the factory used compostie impeller pumps on these engines, and why they equip all of their high performance engines (turbos, etc.) with 160F stats from the factory.
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JP, you are just throwing information that is not possible to measure easily and if you did, should have graphs and data showing it.
About the thermostat. You are measuring the temperature after the thermostat, not at the radiator. All 986s(without center rad) has the same thermal capacity. The only difference is that the proportion of the heat is located in the engine or in the radiator given the same amount of usage and type of usage. The delta temperature(difference between two values) will be different I agree, but it will not affect daily function or be worth it. All you will get is a car that is terrible to use in the morning when its 40-60F outside with much less cabin heat and increase emissions. Considering even california weather that is still half the time used as a commuter.
About the impeller damage. I would love to see pictures. Also considering the person who let a weeping pump long enough for the water pump to fail axially, they wouldn't see the difference in coolant performance anyway. Proper usage you wouldn't see major failures of the pump.
I am just trying show that people should look at a choice in the big scheme of things rather then facing specific problems. Lower Thermostat, under driven pulley, oil cooler, 3000 miles oil change on synthetic , great way to make money on people with more money then time to educate themselves on their car. Listening to "experts".