Racing Thermostat by Mishimoto. Activation Temperature: 68 degrees C. OEM Activation Temperature: 78 degrees C. Mishimoto racing thermostats promote greater cooling efficiency by significantly decreasing high engine temperatures resulting from modified and upgraded turbo applications. Once the engine is fully warmed up, the Mishimoto low-temperature racing thermostat will open at a lower temperature than standard thermostats. This allows the coolant to flow through the engine sooner, thus reducing and maintaining cooler engine temperatures.