The Zero/Sports Radiator Cap controls the water pressure in the cooling system by increasing the boiling point of the coolant. By increasing the boiling point, you decrease the amount of air bubbles that form in the coolant. Air is less effective at removing heat from the engine than coolant, so by reducing the air in your system, your coolant can more efficiently cool your engine.
This cap will not fit the BRZ/FR-S twins.
Vehicles listed in the application tab still may not fit this product. Please do your own research.