Can you handle the pressure? The Koyorad hyper Radiator Cap is for intelligent tuners who demand to extract every ounce of cooling efficiency from their performance machines. Koyorad highly recommends our 1.3 bar Koyorad Hyper Cap (Koyo part number SK-C13) for use with Koyorad All Aluminum Racing Radiators (when applicable). The Koyorad Hyper Cap is made in Japan with the highest quality components ensuring the best possible performance from your Koyorad Racing radiator. By increasing the coolant pressure and raising its boiling point, the faster your engine is relieved of excessive engine heat. The Hyper Radiator Cap withstands an open valve pressure rating of 1.3kg cm2, adding to under your the hood desire for extra toughness an elegant touch of style. *Why is increased Pressure Better?* It’s simple. When water is pressurized, its natural boiling point is increased. Most modern vehicles are equipped with a 0.9 Bar pressure cap. Koyorad’s Hyper Cap is rated at 1.3 Bar which increases the boiling temperature of your coolant to 267.80 degrees Fahrenheit. That is nearly a 56 degree increase over water's normal boiling point. By increasing the boiling point of water, an engine's cooling system will have the added heat capacity, maximizing perfromance under ever-changing racing conditions. For use with all Koyo Radiators.