Radium Fuel Rail Upgrade | 1994-2005 Mazda MX-5 Miata (20-0369)

The BP-powered Miata deserves better than a fuel rail designed around 1990s injector duty cycles.

Whether the plan is boost, E85, or just modern plumbing, the factory rail's fixed lines limit where a 1.8L Miata build can go. The Radium Engineering Fuel Rail for the 1994-2005 MX-5 is CNC machined from extruded 6063 aluminum, black anodized and laser etched, with all three ports machined to 8AN ORB threads. The injector bores are 11mm ID just like the OEM rail, so factory injectors drop right in, and the whole kit is safe for every fuel including E85. This is the rail-only kit, ideal for custom fuel systems.

What You'll Feel

• Freedom to plumb the fuel system your build actually needs, with three real ORB ports
• Factory injectors or upgrades slotting into familiar 11mm bores without adapter drama
• Cooler, more stable fuel with phenolic washers insulating the rail from a heat-soaked intake manifold
• Confidence switching to E85 without second-guessing the rail
• A finish that looks intentional under an NA or NB hood

Features

• CNC machined from extruded 6063 aluminum, black anodized and laser etched
• All 3 ports machined with 8AN ORB (3/4-16 female) threads for adapters, regulators, dampers, and gauges
• 11mm ID injector bores matching OEM, so factory injectors are permitted
• Compatible with all fuel types including alcohol mixtures such as E85
• Reuses the OEM plastic spacers; phenolic thermal insulating washers included to isolate the rail from the aluminum intake manifold
• Stainless steel mounting hardware included; plumbing sold separately

The Details

Radium built this rail for the Mazda 1.8L DOHC BP engine across both chassis generations, and the three 8AN ORB ports are what open it up: run a feed adapter at one end, a Radium direct mount regulator or the OEM-style hardware at the other, and a pulse damper or gauge adapter in the third as your system requires. The phenolic washers are a small detail that earns its place, since the BP's aluminum intake manifold conducts engine heat straight into anything bolted to it, and insulating the rail keeps fuel temperature more consistent on hot days and long sessions. This kit is the bare rail with mounting hardware, so plan your fittings up front. For plug-and-play factory hookups, Radium offers separate plumbing kits: the 1994-1997 version retains the OEM regulator and replaces the feed and return hoses, while the 1999-2005 version retains the OEM pulse damper and feed hose, noting that EGR-equipped cars need the EGR removed for damper clearance.

Kit Includes

• 1x Black anodized, laser etched fuel rail
• Stainless steel mounting hardware
• Phenolic thermal insulating washers
• Plumbing and fittings sold separately

Applications

• 1994-1997 Mazda Miata (1.8L BP)
• 1999-2005 Mazda MX-5 Miata (1.8L BP)
• 1994-1996 Eunos Roadster (1.8L BP)
• Compatible with most Mazda 1.8L DOHC BP engines and factory-size injectors