IAG's Triple Pass Radiator cycles coolant through the core three times, ensuring greater cooling efficiency.  

Before diving into the test results, it’s essential to understand what makes a triple pass radiator superior to its single or dual pass counterparts.

In a traditional single pass radiator, coolant flows through the radiator core once before returning to the engine. Dual pass radiators split this flow into two passes, directing the coolant through the core twice. A triple pass radiator, as the name suggests, directs the coolant through the core three times before it exits.

This design significantly increases the time the coolant spends in the radiator, allowing more heat to be dissipated. By forcing the coolant to pass through the radiator core multiple times, a triple pass radiator ensures more efficient cooling, even under extreme conditions.

• Increased Cooling Efficiency: With more passes through the radiator core, the coolant has more opportunities to lose heat, resulting in lower coolant temperatures overall.
• Optimized Flow Distribution: The triple pass design also improves the flow distribution across the radiator, reducing hotspots and ensuring more uniform cooling.
• Better for High-Performance Applications: Vehicles that are driven aggressively, such as on a racetrack, generate a significant amount of heat. A triple pass radiator is better suited to manage this heat, making it ideal for high-performance and racing applications.

Extreme conditions call for optimized cooling and flow. This is where the Triple Pass comes in, the ideal solution for high-performance applications.

The thicker the core, the greater the surface area available for heat exchange, which translates into better cooling performance.

Core thickness is a critical factor in a radiator's ability to dissipate heat. The thicker the core, the greater the surface area available for heat exchange, which translates into better cooling performance. Our 42mm Street Series and 55mm Competition Series radiators feature significantly thicker cores compared to the stock OEM unit. The 42mm core offers a substantial upgrade for daily driving and light track use, while the 55mm core is designed for extreme performance, providing maximum cooling capacity for high-power and heavily modified vehicles.

In addition to the increased core thickness, our radiator kits come complete with new silicone radiator hoses, which offer improved durability and heat resistance compared to standard rubber hoses. Keen observers may notice that the upper radiator hose inlet location has been updated to accommodate the triple pass design. These kits are also fully compatible with OEM fans and shrouds, ensuring a straightforward installation process without the need for additional modifications. This compatibility allows for easy integration into your vehicle while enhancing its cooling system’s performance, making it a perfect upgrade for those looking to push their vehicle’s limits on the track or maintain optimal cooling in everyday driving scenarios.

For our testing at Summit Point Raceway, each radiator was subjected to identical conditions, including the same driving patterns and load conditions. Some lap traffic may have affected IAT temps. This testing occurred on a day with rising track temperatures, which also led to higher intake air temperatures (IATs). Despite these challenging conditions, our radiators demonstrated exceptional cooling performance.

For consistent results, we'll be testing on the Main Circuit track at Summit Point Raceway in West Virginia.

Peak Coolant Temperatures

The stock OEM radiator's peak temperature of 230°F highlights the limitations of standard cooling systems under high-stress conditions. Our 42mm Street Series radiator, which incorporates triple pass technology, reduced this peak temperature to 212°F. This substantial improvement is crucial for maintaining engine efficiency and longevity during spirited driving. The 55mm Competition Series radiator, also utilizing triple pass technology, further reduced the peak temperature to 206°F. This significant 24° drop compared to the stock radiator emphasizes its capability in handling extreme track conditions, making it an excellent choice for high-performance vehicles. Together this testing indicates that the IAG 42mm Street Series Radiator is 19% more efficient than OEM, while the IAG 55mm Competition Series Radiator is 20.2% more efficient than OEM.

Intake Air Temperatures

While higher IATs were recorded during testing—104°F for the 42mm Street Series and 100°F for the 55mm Competition Series, compared to the stock radiator’s 95°F—these increases were due to the day's heat and rising track temperatures. Importantly, the superior coolant temperature management of our triple pass radiators demonstrates their effectiveness even in challenging conditions.

Coolant System Pressure

Another key observation from our testing was the significant reduction in coolant system pressure with the use of our 42mm Street Series and 55mm Competition Series radiators. Pressure readings were taken at two critical points: the coolant crossover pipe and the thermostat housing. At the coolant crossover pipe, the stock OEM radiator recorded a pressure of 19 psi, whereas the 42mm Street Series radiator lowered this to 17 psi, and the 55mm Competition Series radiator further reduced it to just 12 psi. Similarly, at the thermostat housing, the stock radiator showed a pressure of 11 psi, the 42mm recorded 4 psi, and the 55mm dropped to an impressive 3 psi.

This reduction in system pressure is indicative of the improved flow dynamics and heat dissipation capabilities of our radiators. Lower system pressure not only reduces the stress on hoses and other cooling system components, but it also enhances overall cooling efficiency. By lowering the pressure throughout the system, our radiators help ensure more consistent and reliable cooling, especially under the high-temperature conditions encountered on the track. The graph representing these pressure differences uses the same color coding as before: red for the stock OEM radiator, green for the 42mm Street Series, and blue for the 55mm Competition Series.

Our extensive testing at Summit Point Raceway highlights the superior performance of IAG Performance’s 42mm Street Series and 55mm Competition Series Triple Pass Radiators compared to the stock OEM radiator. With advanced triple pass technology, these radiators deliver significantly lower peak coolant temperatures—212°F for the 42mm and 206°F for the 55mm, compared to 230°F for the stock radiator. This enhanced cooling efficiency is crucial for maintaining engine performance, especially under demanding conditions.

Additionally, the thicker core design of our radiators provides a greater surface area for heat exchange, further enhancing their cooling capabilities. The 42mm core offers a substantial upgrade for everyday driving and light track use, while the 55mm core is tailored for extreme performance, making it ideal for heavily modified and high-power vehicles. These kits also include new silicone radiator hoses for improved durability and are fully compatible with OEM fans and shrouds, ensuring an easy and straightforward installation process.

IAG has developed the 42mm Street Series Triple Pass Radiator for everyday driving, whereas the 55mm is suited for heavily modified race applications.

The increased core thickness of our radiators significantly increases the surface area for heat exchange, optimizing heat dissipation and boosting the overall cooling efficiency.  

Our testing also revealed significant reductions in coolant system pressure with the use of our radiators. At the coolant crossover pipe, pressures were reduced from 16 psi with the stock radiator to 14 psi with the 42mm and just 10 psi with the 55mm. Similarly, at the thermostat housing, pressures dropped from 11 psi with the stock unit to 5 psi with the 42mm and an impressive 4 psi with the 55mm. These reductions in system pressure not only lessen the stress on cooling system components but also contribute to more consistent and reliable cooling, especially under high-temperature conditions.