Well I just got back from some "hill climb" action. A mountain road, uphill, very twisty with many 25 and 30 mph posted speed limit corners, other wise, 55 mph. I've made that run before, with straight water. Using 2nd gear and high rpm or third within the power band rpm. In either case, coolant temps were identical with straight water. BUT!!!!
Oil temps are certainly higher.
Oil temp is higher when I'm simply cruising on the freeway as well. With water the
oil was always trailing the coolant by 15 C degrees. With Evans those temps, for the most part, track each other almost identically. I never saw the oil temp exceed the coolant temp and after a long steady freeway cruise would slowly drop 5 degrees or so below coolant temp.
It's strange seeing the higher oil temps, as someone else mentioned they also observed (on another thread). Temps seem to go higher quicker across the board and come down as quickly too! Once you have reached operating temp (180 degrees with thermostat in my case) any sudden accelleration, down shifting and hammer down type moves, all but instantly will cause a temperature increase. Around town it's the same thing. I pull off the freeway at just under 90 c and at the first stop light I'm at a 100 c, just like that (oil temp as well)! With water, it would slowly rise to a 100 c around town, a few stop lights, some traffic congestion, oil temp would take much longer but eventually would increase as well. Now all I have to do is slow down and the temps (water and oil) start to climb.
I was pushing it hard and doing what I thought would generate the max load and heat on the engine up the twisty mountain road. Like running 2nd gear at high rpm or third at mid rpm, full throttle on the straights, braking hard for the corners, powering out. 105 c, both water and oil. I was running higher water and oil temps than that at Infineon (straight water). So I guess I was not able to duplicate the loads of a real race track. I have a hunch it will be about the same as water.
HOWEVER, I remain concerned about the possibility of higher oil temps on a race track with Evans instead of water!
I'm not running an oil cooler, perhaps I should now reconsider that. In Hawaii it was always a challenge to get my oil temps up as high as I wanted it to be. The LAST thing I wanted was an oil cooler!
The expansion rate, on my car, is significant! Easily two inches, gotta be more than that even. When cold my surge tank is only half full. After an intense high rpm run (like a hill climb) my overflow bottle is half full! I suspect it's "pump pressure" as much as expansion. Water pump pressure pushing coolant out and into the overflow. Surprisingly that water is pulled back in very quickly as well. Cooling down from 100 c to 90 c the coolant is recovered back into the system, this happens very quickly. To check the overflow I need to get it up to a 100 c, run some high rpm, pull over quick and check to see how full the bottle is. If I shut down the engine it will take some time for the overflow coolant to be sucked back in. But if I drive off normally and the temp drops to 90 c (or less) that water is back in the engine already. Strange that...
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