The IAG Triple-Pass Competition Series 55mm Radiator is a high-performance aluminum radiator designed to work with 2008-2014 Subaru WRX and 2008-2021 STI (GV/GR/VA chassis models). Engineered to cool more efficiently than the OEM radiator, this lightweight upgrade is perfect for competition applications and engines with performance modifications that have a tendency to run hot. The all-aluminum construction provides superior heat dissipation, ensuring your engine operates at optimal temperatures even under extreme conditions. IAG’s Competition Series Triple-Pass 55mm Radiator is the perfect choice for enhanced cooling performance and reliability.

The IAG Competition Series Radiator utilizes an advanced 3-pass design, featuring baffles located inside the end tanks that route the coolant through the radiator three times from inlet to outlet. Unlike the single-pass design of the OEM radiator, IAG’s innovative approach ensures the coolant stays inside the radiator longer, resulting in a significant increase in cooling efficiency. On average, the 3-pass design improves cooling performance by 10-20% over the factory radiator, providing your engine with better thermal management even during intense performance scenarios.

See our Performance Under Pressure Blog for test results.

The IAG 55mm Competition Series Triple-Pass Radiator is constructed from lightweight and durable aluminum, making it less likely to crack or bend even under high temperatures. Aluminum's excellent heat conductivity and rapid absorption properties allow the hot coolant to cool more quickly as it circulates through the tubes. Additionally, aluminum offers exceptional resistance to corrosion, ensuring a long lifespan and reliable performance. The IAG 55mm Triple-Pass Competition Series Radiator is made in the USA and built to meet the demands of high-performance applications while providing efficient cooling and durability.

The IAG Competition Series Triple-Pass Radiator features a 55mm (2.165”) core and is designed for compatibility with OEM radiator fans using the original mounting positions. The lower radiator outlet remains in the stock location, utilizing the included lower hose. The upper radiator inlet has been relocated and requires the included IAG 4 Ply Silicone Upper Radiator Hose (Part #IAG-ENG-2304) for installation. A -6 AN Male Fitting is welded on one end for applications that need a coolant expansion tank. For applications that do not require this fitting, a -6 AN female cap is included.