Koyo Performance Radiator – Mazda RX-7 FD3S 1.3L Twin Turbo N-FLO Dual Pass 1991–1995
Application: Mazda RX-7 | FD3S (2D Coupe) | 13B-T 1.3L Twin Turbo Petrol RWD | Manual Transmission Only
Part Number: HH060644N / KH060644NU06
The FD RX-7 is one of the most thermally demanding platforms in the performance world — a sequential twin-turbo rotary in a compact, tightly packaged engine bay that generates serious heat. The factory cooling system was engineered to cope, but when you're pushing the FD harder or running more boost, it quickly becomes the limiting factor.
Koyorad's N-FLO Technology was developed specifically for applications like this. Where the factory inlet and outlet locations allow proper placement, Koyorad precision-welds aluminium partitions into the upper and lower tanks, creating a double-pass coolant flow path. This keeps coolant in the radiator longer, transferring significantly more heat to the surrounding air before returning to the engine — a meaningful upgrade over a conventional single-pass design.
The result is a direct bolt-in radiator that retains all OEM fan shroud mounts and stock hose connections, with no engine modifications required. Built to the same exacting standards as every Koyorad All Aluminium Racing Radiator — Nocolok furnace brazed, precision TIG welded by hand, and triple pressure tested.
Why Koyorad?
-
N-FLO Dual Pass Technology — Aluminium partitions in the upper and lower tanks create a double-pass coolant flow, maximising heat transfer and cooling efficiency.
-
Precise Tube & Fin Alignment — Strict quality control ensures optimal coolant flow and maximum heat transfer efficiency across the entire core.
-
Nocolok Furnace Brazing — All tubes, fins, headers, and brackets are bonded in a state-of-the-art Nocolok furnace, creating a structure that resists vibration, road debris, and the elements.
-
Billet Filler Neck — Precision-machined billet filler necks are fitted to every unit for superior strength, durability, and a reliable seal.
-
OE-Specific Mounting & Hand-Crafted Heliarc Welds — Application-specific mounting points and individually hand-welded construction ensure a pain-free install and the strongest possible aluminium-to-aluminium bond.
