90 zr1 oil temps on track

[ZRconekiller]

Hello everyone my 90 has mainly been an autocross car for the past 2 years but finally had the opportunity to get on a road course again this past weekend. Everything worked fine but i did notice the oil temp gauge did get hot almost pegged. 1 cool down lap and the gauge returned to normal. Curious to hear everyone's thoughts?

[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.

[ZRconekiller]

Originally Posted by 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.

Thanks Marc after looking at the logs for a 1:21 second lap the car may have been above 6000 rpm for 8 seconds if my logs are correct. It was about 70 degrees outside so not overly warm. Would 8 seconds a lap really cause that? Thanks again!

[Marc Haibeck]

Eight seconds is no problem. I was thinking in terms of about 50% of your lap time.

Is the radiator clean? Is the thermostat okay? Here is an easy performance test. Warm the engine up until it is hot. Then unplug the connector on the small sensor on the AC line next to the dipstick. Both fans will turn on. With an ambient temperature less than 80 degrees the engine should cool to 200 degrees in about two minutes. The center of the sweep on the temperature gauge is 200 degrees.

Is the oil temperature gauge correct? Use a data scanner to read the digital temperature. It comes from a separate and more accurate sensor.

[gtcollins@maxnet.co.nz]

When tracking my ZR-1 the oil temperature gets hot had it just under the cross hatching water temperature doesn't seem to move and the oil temperature comes down fearly quickly once I ease up on the gas

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