Radium Top Feed Primary Fuel Rail Conversion Kit | Mazda 13B-RE/REW (20-0445)

Rotaries punish lean conditions instantly, and the primary injectors are the ones firing every single revolution.

The Radium Engineering Top Feed Primary Fuel Rail Conversion Kit for the Mazda 13B converts the primary injector positions in the rotor housings to modern top feed injection: a high flow rail for the 13B-RE and 13B-REW, anodized black for compatibility with all popular fuel types including E85, with a large internal bore supporting all necessary engine power requirements. Three 8AN ORB ports handle plumbing, the extra center port hosting accessories like the OEM fuel temperature sensor (via the 14-0421 adapter), a pressure transducer, or a Radium fuel pulse damper. Insulating phenolic spacers, washers, and stainless hardware prevent thermal energy from conducting into the fuel, and the included 14mm lower injector seats carry Viton O-rings suitable for boosted applications, compatible with or without the OEM diffusers in place. Injectors sold separately.

What You'll Feel

• Modern top feed injectors on the ports that fire every revolution of the rotors
• Fueling stability for the boosted, E85 rotary builds that punish lean spikes hardest
• Boost-sealed injector bases from the Viton O-ring seats
• OEM fuel temperature sensor retained via the center port and 14-0421 adapter
• Cooler fuel through phenolic isolation from housing heat

Features

• High flow primary rail for the 13B-RE and 13B-REW rotary engines; converts to top feed injection
• Anodized black aluminum, large internal bore, all fuels including E85
• 3x 8AN ORB ports; center port for OEM fuel temp sensor (14-0421), pressure transducer, or pulse damper
• 14mm lower injector seats included, Viton O-ring sealed, compatible with or without OEM diffusers
• Insulating phenolic spacers, washers, and stainless steel hardware included
• Verified injectors: Injector Dynamics ID1050/ID1300/ID1700/ID2600-XDS-34-14-14 (NOT included)

The Details

The conversion's engineering lives in the seats: the OEM primary injector counterbores measure 16mm while modern injector lower O-rings standardize on 14mm, so the machined aluminum seats press into the iron ports, seal on their own O-rings, and give top feed injectors a correct 14mm home, with the design specifically accommodating the OEM fuel injector diffusers either retained or removed. Injector selection is fully documented, with the ID XDS-34-14-14 family verified as direct fitments. Plumbing runs entirely through 8AN ORB, so feed, crossover to the secondary rail, and accessories all use Radium adapter fittings selected per your system; O-rings lubricated at every step per Radium's instructions. Pairs with the 20-0447 secondary rail for the complete REW conversion.

Kit Includes

• 1x Black anodized high flow primary fuel rail
• 14mm lower injector seats with Viton O-rings
• Insulating phenolic spacers and washers, stainless steel hardware
• Fuel injectors and port fittings NOT included

Applications

• 1992-2002 Mazda RX-7 FD3S (13B-REW)
• 1990-1995 Mazda/Eunos Cosmo (13B-RE)
• Verified: ID1050/1300/1700/2600-XDS-34-14-14 injectors