N-Flow HH Series Hyper Core Radiator, 48mm Thick

The Koyo N-Flow radiator is a high-performance cooling solution specifically designed for the 89-91 S5 Mazda RX-7 chassis. This HH Series radiator utilizes Koyo's N-Flo Dual Pass design, also known as Z flow, which routes coolant through the core twice. This increased coolant path time results in enhanced cooling efficiency, estimated at 30%-40% over stock and 10% over standard R-Cores without N-Flow technology. It is ideal for extreme cooling demands and can be used with a Front Mount Intercooler (FIMC). Constructed from aircraft-quality aluminum with heli-arc welded cores and Nocolok-R brazing, this radiator is built to withstand the rigors of high-revving, high-performance engines, making it suitable for both naturally aspirated and Turbo II applications. The 48mm Hyper Core offers superior thermal performance compared to stock radiators, providing an estimated 20% to 30% increase in cooling capacity. It features OE-specific mounting for a direct, no-modification installation and includes a billet aluminum filler neck and a 1/8” NPT female accessory fitting. The direct fit design ensures it bolts on like the OEM unit. This radiator is exclusively for manual transmission vehicles. Automatic transmissions will require an external transmission oil cooler. Fitment is specific to the Series 5 FC3S chassis, and it requires the use of OEM Series 5 side brackets, as Series 4 brackets are different. The top coolant level sensor provision is retained.