STM Performance Parts for Evo DSM RS3 Supra Huracan Subaru

Koyo Racing Radiator Cap Hyper Red



Fits these Applications:
All Koyo Aluminum Radiators with Fill Necks and most Aftermarket Radiators
2003-2006 Mitsubishi Lancer Evolution VIII-IX
2008-2015 Mitsubishi Lancer Evolution X
1990-1999 DSM (Mitsubishi Eclipse GST & GSX, Talon TSi & Laser Turbo)
2002+ Subaru WRX & STi
2009+ Nissan R35 GT-R
2003+ Nissan 350Z & 370Z
1988-1991 Honda Civic
1990-1993 Acura Integra
1992-2001 Honda Prelude


The Koyorad Hyper Cap withstands an increased valve pressure rating of 1.3kgf/cm2 (1.3 bar) (18.9 psi) (130 kPa) which increases the boiling point of water and relieves high performance engines of excessive heat. This Koyorad Hyper Cap is manufactured in Japan from high quality components to ensure longevity and performance from your Koyorad Racing radiator.

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°F. That is nearly a 56° 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.

Fits most aftermarket radiators, and most Mitsubishi, Subaru and Nissan applications.

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