Quote:
Originally Posted by ZDan
You'd run thicker oil at the track not to preserve its viscosity after it cools back down from elevated temps, but to have the appropriate viscosity at elevated temperatures. I.e., if your oil runs up to, say, 275F at the track, a 30, 40 or 50 weight oil is going to be a lot closer to the right viscosity than a 0W20, which might be dangerously thin at that temperature.
(Obviously you'll want synthetic if you are running elevated oil temperatures, whatever weight you run.)
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Your bulk average oil temperature should not normally be that much more than your coolant temperature, however as I have said before the temperature in the connecting rod bearings and shear loads and resulting film thickness are what is important to bearing protection.