PIAA SS-R Radiator Caps are designed to withstand extreme heat conditions and engineered to hold more pressure than those of stock applications. PIAA Radiator Caps are constructed of full stainless steel and utilizes a urethane seal. Available for: Subaru, Toyota, Honda, Nissan, Lexus, Infinity, Mazda, and Mitsubishi vehicles.
In a cooling system, a higher pressure equates to a higher boiling point for the coolant. Higher coolant pressures also transfer heat from the cylinder heads more efficiently. We recommend using a radiator cap with the highest pressure rating that the radiator is designed to accept. In general, performance radiators will accept 22-24 PSI, and professional racing radiators will accept a 29-31 PSI.
The coolant will typically only build to 16-18 PSI, due to expansion up to 200°F. However, if the engine does overheat due to external factors, the pressure inside the cooling system could reach as high as 28 PSI. Once the radiator cap has opened and vented coolant, the engine will not cool down until it has been turned off. The radiator cap is basically a "safety valve", so always use the highest pressure radiator cap that the radiator will tolerate. If you are unsure of the pressure rating for your radiator, check with the manufacturer for the maximum recommended operating pressure.
Features & Benefits:
- Prevents overheating
- Cooler engine to improve performance
- Lessens boiling accidents
Normal atmospheric pressure = 98kPa, so add this number to the above 'Additional Pressure' value to get the improved working pressure with the use of PIAA SS-R Radiator Cap. E.g. 98kPa + 88kPa = 186kPa, or 98kPa + 108kPa = 206kPa. The right table shows you the enhanced boiling temperature as a result of increased pressure.
PIAA's unique pressure-regulating safety valve constantly maintains proper rated pressure in real-time, no matter whether the internal radiator pressure increases or decreases. This safety valve also doubles as a boiling prevention button. Driver and mechanic can depress the button to release built-up pressure so as to minimize over-boiling spilling.
PIAA SS-R Radiator Cap 54S & 56S