Silver Raw Steel High Temperature Thermostat (MMTS-F2D-08H) by Mishimoto. 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.