Radium 20-1113 Top Feed Primary Fuel Rail for 1990-2002 Mazda RX7 13B-RE/REW

Vehicle Fitment

• 1990-1995 Mazda/Eunos Cosmo (13B-RE, Twin Turbo)
• 1992-2002 Mazda RX-7 FD3S (13B-REW, Twin Turbo)

Fitment Notes

• This is the primary injector location fuel rail only. A separate secondary fuel rail is required for a complete dual-injector setup.
• Fuel injectors are NOT included and must be sourced separately. Required injector specs: 34mm body height, 14mm upper O-ring, 14mm lower O-ring (e.g., Injector Dynamics 1050.34.14.14, 1300.34.14.14, 1700.34.14.14, or 2600.34.14.14).
• Not compatible with OEM-height or 60mm tall injectors in the primary position - only 34mm short-body top-feed injectors are supported.
• Compatible with all popular fuel types including gasoline, E85, ethanol, and methanol.

Features

• Converts the OEM primary injector location from side-feed to top-feed, enabling the use of high-flow aftermarket universal fuel injectors.
• Large internal bore provides high flow capacity to support all engine power levels including heavily boosted builds.
• Three 8AN ORB ports allow flexible fuel system plumbing - inlet, outlet, and an extra center port for accessories such as a fuel pulse damper, pressure transducer, or OEM fuel temperature sensor.
• CNC-machined anodized aluminum construction is compatible with all fuel types including E85 and alcohol blends.
• Thermal insulating spacers and washers included to prevent heat from the rotary engine from conducting into the fuel.
• Billet aluminum injector seats included - compatible with or without OEM fuel injector diffusers in place.

Specifications

• Position: Primary (iron/rotor housing injector location)
• Injector Style: Top-feed conversion
• Required Injector Height: 34mm (short body)
• Required Injector O-ring: 14mm upper, 14mm lower
• Fuel Rail Ports: Three 8AN ORB (1-1/16"-12 threads)
• Material: CNC-machined anodized aluminum (black)
• Hardware: Stainless steel

Included Components

• 1x Anodized billet aluminum primary fuel rail
• 2x Anodized billet aluminum injector seats
• 2x Thermal insulating spacers
• Stainless steel mounting hardware

Product Description

The Radium Engineering 20-1113 is a top-feed conversion primary fuel rail designed for the Mazda 13B-RE and 13B-REW rotary engines found in the 1990-1995 Eunos/Mazda Cosmo and 1992-2002 Mazda RX-7 FD3S. It replaces the OEM side-feed injector setup at the primary (iron) location, allowing the use of widely available high-flow top-feed aftermarket fuel injectors. This opens up significantly more injector options for high-power builds, including E85 and methanol applications.

The rail features three 8AN ORB ports for versatile fuel plumbing, with the center port available for accessories such as a Radium fuel pulse damper, pressure transducer, or the OEM fuel temperature sensor. Included thermal spacers and washers isolate the rail from engine heat to protect fuel quality. Injectors are not included - required injectors must be 34mm tall with 14mm upper and lower O-rings, such as the Injector Dynamics XDS series in 1050, 1300, 1700, or 2600cc variants.