90 zr1 oil temps on track

[Marc Haibeck]

Were you running a lot over 6000 rpm? If so the water pump cavitates at about 6200 rpm. The coolant flow slows so the coolant temperature is false. The engine gets hot due to low coolant flow. The oil temperature remains accurate and basically indicates the engine temperature.

You can drive around the problem by staying below 6000 rpm, or install an underdrive water pump pulley and the cavitation speed will move up to about 6500 rpm. In addition to that, installing an ATI crankshaft damper with an underdrive pulley will increase the cavitation point to about 7400 rpm.