Koyorad HH Series N-Flo Aluminum Racing Radiator – 1989–1992 Mazda RX-7 FC3S | Manual Transmission

Protect your FC3S's legendary rotary engine from heat failure with the ultimate cooling upgrade — the Koyorad HH Series N-Flo Racing Radiator (HH060643N). Engineered specifically for the 1989–1992 Mazda RX-7 FC3S with manual transmission (Turbo and Non-Turbo), this radiator is essential for street performance and track durability. The rotary engine is notoriously heat-sensitive — Koyorad addresses this with a robust all-aluminum construction featuring a thick 48mm HH Hyper Series core and their innovative N-Flo Dual Pass Technology, forcing coolant through the core twice for maximum heat transfer efficiency.

⚠️ Manual Transmission Only: This radiator is engineered for manual transmission FC3S RX-7 models only. Automatic transmission variants require a different radiator. Verify your transmission before ordering.

Key Features

• N-Flo Dual Pass Technology: Internal tank partitions force coolant through the core twice, significantly increasing coolant residence time and heat dissipation efficiency over standard single-pass radiators — critical for the heat-sensitive rotary engine under sustained high-load and track use
• 48mm HH Hyper Series Core: Thick 48mm high-density core engineered for extreme heat loads common in turbocharged and high-RPM rotary applications — substantially more cooling capacity than the factory radiator
• All-Aluminum Construction – TIG-Welded & Nocolok-Brazed: Fully TIG-welded, Nocolok-brazed all-aluminum construction eliminates the weak points of the OEM plastic end tanks — superior durability and longevity for high-performance and track applications
• Direct OEM Fitment – Factory Fan Shroud Mounts Retained: Designed for direct bolt-in installation retaining the factory fan shroud mounts — no modification required for a clean, factory-integrated installation
• 1/8" NPT Accessory Port: Includes a 1/8" NPT port with plug for easy integration of aftermarket coolant temperature sensors and gauges — essential for monitoring the rotary's heat-sensitive cooling system
• Billet Aluminum Filler Neck: Precision-machined billet aluminum filler neck for superior sealing and long-term durability

Specifications

• Type: Racing Radiator
• Series: HH (Hyper Series)
• Technology: N-Flo Dual Pass
• Core Thickness: 48mm
• Construction: All-Aluminum, TIG-Welded, Nocolok-Brazed
• Accessory Port: 1/8" NPT (with plug)
• Transmission: Manual Only
• Fitment: 1989–1992 Mazda RX-7 FC3S (Turbo & Non-Turbo) — Manual Transmission
• Part Number: HH060643N

Note: Manual transmission fitment only — automatic transmission FC3S requires a different radiator. A coolant flush and refill is required after radiator installation. Verify your specific FC3S configuration (Turbo vs Non-Turbo) and model year before ordering. Professional installation recommended.