I took my laser pyrometer to the track this morning where I had sponsored a car. This is a dirt track about 6 km long, lots of 5 kph curves, and a couple of straight-a-ways, 10 laps per race. As each car came in I checked temperatures of various components on the cars (mostly 1600 to 2000 cc Toyotas, a Subaru, a couple of Nissans. The question is: Everyone was running without a thermostat, looking for the most possible cooling, yet none had actual temperature gauges…. Just the range gauge. Most water temperatures coming out of the block were running in the 77 to 80 C range at the end of the victory lap, while oil temperatures at the filter were running between 107 and 110. (Exception being one where the water was 110 and the oil 155 C, but the radiator was blocked with mud). The questions are: 1. Wouldn’t it be better to run with the thermostat and keep the water temperature closer to the 90 C range? 2. With a 30 C difference between water and oil temperatures, isn’t there a risk of cracking or other internal damage? 3. One car had an oil cooler installed with an adapter plate that I assume filters the oil before sending it to the cooler, then receives the cooled oil to mix back with the rest of the oil. From the size of the tubing it couldn’t have been cooling more than about 10%. Oil at the filter was 110 C like the others, but 75 C coming out of the cooler. Are all coolers only partial flow, or who can offer a better setup.