The Cosworth 154 Degree Thermostat has been designed to keep the 2JZ application cool, and running at optimal temperatures. The Cosworth 154° Thermostat has been engineered and developed to fight high temperatures during high performance driving.
When compared to other thermostats, the Cosworth thermostats have the ability to control the flow of coolant once the valve opens. And the Cosworth units have the ability to stabilize the engine temperatures under extreme conditions where the engine could be going through Dyno or tuning conditions.
The opening will begin at 154°F, and will keep your engine operating at cooler temperatures during high performance driving conditions. With reduced operating temperatures, you will have improved volumetric efficiency, as well as knock limit.