So, I was in the field for work all week and decided to take a detour through the Catskills to get home. Let me start by saying that at 79f running the heater wasn't too bad. As I drove downstate NY the temps rose to close to 95* and it was brutal. I was generally in 3rd or 4th at around 4-6k rpms the entire ride.
In this first pic the heater is OFF. At 215f coolant temps oil was stable at 248f and I was beating on the car. On track I'd expect to see coolant go up a bit more and oil hit as high as 280-290f since it's a steady 20-30minutes of abuse instead of short bursts of up and then down hill coasting.
You can see the delta in temperatures between now and a few minutes ago when the heater had been on full blast. In order to achieve those lows I had to cruise at 60mph @2krpms. At cruising speed, and in town, the heater was doing a fantastic job of keeping all temps low. Coolant had been on target at 185f and oil was as low as 235f.
Here is a pic of what thing looked like with the heater on and driving HARD:
As soon as I started back up the hills, at 80+ in 3rd, oil went back up to about 246f while coolant temps stayed low at 185f. Albeit the rise in oil temps did take longer. The heater blowing definitely helped keep coolant temps down, but the increase in cooling ability was only delaying the inevitable rise in oil temps.
How could coolant temps stay at 185f while oil rose from 235f back up to 246f? that is only 2f less than when coolant temps were at 215f and oil was at 248... This goes back to my point that there is a breaking point (q-dot) to how fast the cooling system can remove heat from the engine.
So basically a 30f reduction in coolant temps were helping me see 2-3f lower oil temps (in abusive conditions). At <20 mph, and at highway speeds, running the heater did indeed help keep ALL temps lower. After doing all sorts of variations of testing over those 4 hours I can see how people might jump to the conclusion a radiator helped lower their oil temps but as soon as they got on track their oil still overheated.
I had better pics of how coolant stayed low with the heater on and oil went back up (in some cases back up to 249f as coolant was below 190f), but my phones microsd card is going bad and they are currupt.
After all this, do I agree there is room to upgrade the radiator? YES. Do I think a radiator is going to solve oil problems on track? NOPE. Hence, why people are obsessed with upgrading their oil coolers!
Here is what the route looked like for reference:
