Koyo Hyper Radiator Cap

Koyo Hyper Radiator Cap image 1
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by Koyo
Category: Radiator Caps
Product Review: 0 Star Rating

Extract every ounce of cooling efficiency from Koyorad All Aluminum Performance Radiators with a genuine Koyorad Hyper Cap! This 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. A genuine Koyorad Hyper Cap is recommended for use with every Koyorad All Aluminum Performance Radiator (when applicable). 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 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 more information on this product you may visit the Koyo website.


Part Number



Universal Koyo Hyper Radiator Cap
Universal (May not fit all vehicles or require modification)
A-Type Deep Plunger type (fits all KOYORAD radiators w/ fillernecks)
Scion FR-S
2013-2017 Scion FR-S

B- Type Shallow Plunger type (FR-S/BRZ/GT86)

Subaru BRZ
2013-2018 Subaru BRZ

B- Type Shallow Plunger type (FR-S/BRZ/GT86)


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