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Koyo Performance Radiator – Mazda RX-7 FD3S 1.3L Twin Turbo N-FLO Dual Pass 1996+
Application: Mazda RX-7 | FD3S (2D Coupe) | 13B-REW 1.3L Twin Turbo Petrol RWD | Manual Transmission Only | 1992 and later
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 high-performance radiator designed for 1996 and later FD3S RX-7 models. It retains the factory-style fan shroud mounting points and stock-style hose connections, with no engine modifications required. Because late-model FD3S cars received small changes to the factory shroud and cooling-system layout, minor shroud or hose adjustments may be required during installation. 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.
Important Fitment Notes for 1998+ FD3S Models
Late 1998–2002 Series 7 and Series 8 models use a factory plastic fan shroud with slightly revised mounting-tab positions. This radiator is pre-drilled for the earlier 1993–1995 shroud configuration, so one or two fan shroud bolt holes may not align perfectly on a later car. In most cases, the shroud can be secured by carefully slotting the plastic mounting tabs or by using suitable zip ties or custom brackets to secure the fan assembly.
Some late-model variants, including certain Spirit R models, may also have slightly different angles at the front engine covers and water-pump necks. Standard aftermarket silicone radiator hoses based on the 1993–1995 layout will usually stretch or bend into position, but trimming the hose length may be required to prevent kinks in a 2002 engine bay. Check hose routing and clearance carefully before final tightening.
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 strong aluminium-to-aluminium bond.
Specifications
| Part Number | HH060644N / KH060644NU06 |
| Core Type | N-FLO Dual Pass |
| Core Thickness | 48mm |
| Core Dimensions (H × W) | 313 × 609/629mm |
| Tube Pitch | 55/55 × 647mm |
| Inlet / Outlet Diameter | Ø38mm (top & bottom) |
| Construction | All Aluminium, Nocolok Brazed, Heliarc Welded |
| Transmission | Manual (MT) Only |
| Fan Shroud | Factory-style mounting points; late-model shroud bolt holes may require minor slotting or alternative securing |
| Hoses | Stock-style hoses generally compatible; late-model hose trimming may be required to prevent kinks |
| Fitment | Designed for 1992+ FD3S; minor late-model shroud and hose adjustments may be required |
Cross Reference
| Koyorad | HH060644N / KH060644NU06 |
| Mazda OEM | N3A1 15 200 / N3A1 15 200A |
Fitment
| Year | Make | Model | Chassis | Submodel |
|---|---|---|---|---|
| 1992+ | Mazda | RX-7 | FD3S (2D Coupe) | 13B-REW 1.3L Twin Turbo Petrol RWD, manual transmission; late-model fitment notes apply |
Sold individually. Manual transmission fitment only. Late-model FD3S shroud and hose adjustments may be required. Lead times may apply — contact us at Coore for availability and shipping estimates.
Coore Performance & Aftermarket is an Authorised Australian Distributor of Koyorad Performance Radiators.
Shop with confidence — all Koyorad products sold through Coore are genuine, backed by manufacturer support, and shipped from Australia.
