While my friends are still tearing up the track at NCM, I’m looking at logs. Figured out the bottleneck in my cooling system: Engine oil.
You can click for a full-sized view. In the bottom chart, you can see the water temperature (green) stabilize along with the engine oil (white) while the transmssion continues to climb until it stabilizes a bit later (red).
The first good bit of the log is the out lap, so not WOT.
When I started hammering on it, the oil temp suddenly rises, and the water follows. The transmission’s temperature bumps every time I got WOT. All of the increases are correlated with high torque converter slip events. At NCM there’s not a lot of time between WOT segments. There’s the front straight, but the back esses and the stretch between Deception and Tabletop are so gently curved I was flat through there, so the track has essentially three ~2000′ straights. The back and middle sections are also uphill. So those put a bunch of heat in the converter. The car can’t shed it fast enough.
So, common element here is the radiator. The engine oil and transmission oil pass through coolers in the radiator. The transmission now has a huge auxiliary cooler, but not the engine oil. The heat from the engine oil is dragging the water temp up, which is pulling up the transmission temp. Once the water temperature exceeds the transmission temp, the water is going to start shedding heat into the the transmission circuit instead of the other way around. Thermodynamics. All three systems will want to reach the same temperature. Sadly, I think that temp would be somewhere close 250.
So I probably need to disconnect the engine oil cooler loop in the radiator and run that through its own exchanger.