Radium Engineering Fuel Rail | 2001-2005 Honda Civic Si and 2002-2006 Acura RSX Type-S (20-0230-02)

Every K-series intake manifold swap eventually asks the same question: is the fuel rail keeping up?

The Radium Engineering Fuel Rail for the Honda K-Series answers it for good: a large 0.69" internal bore supporting all necessary engine power requirements, CNC machined from extruded 6063 aluminum, media blasted, black anodized, and laser etched. This is an upgrade rail, meaning the 14mm ID injector bores match OEM so factory injectors reinstall directly, and it fits every OEM Honda K-series intake manifold (RBC, RBB, RRC, PRB, and more): if the manifold fits the OEM rail, it fits this one. Phenolic thermal insulating washers isolate the rail from manifold heat, stainless hardware is included, and all fuels including E85 are welcome. Not compatible with the direct-injected K20C1.

What You'll Feel

• Rail volume that stays ahead of the injectors on boosted and high-rpm K builds
• Universal manifold compatibility across the RBC/RBB/RRC/PRB alphabet
• Cooler fuel courtesy of phenolic washers thermally isolating the rail from the manifold
• Factory injectors reinstalled without drama in true 14mm OEM-spec bores
• Port flexibility for a damper, gauge, or custom plumbing as the build evolves

Features

• Large 0.69" internal bore; CNC machined extruded 6063 aluminum, media blasted, black anodized, laser etched
• Upgrade rail: 14mm ID injector bores accept factory or OEM-equivalent injectors (same height, matching upper and lower O-ring dimensions)
• Compatible with all OEM Honda K-series intake manifolds (RBC, RBB, RRC, PRB, etc.)
• Reuses OEM insulating spacers (Honda 16638-PNA-000); phenolic thermal insulating washers included
• Stainless steel mounting hardware; all fuel types including E85
• NOT compatible with the direct-injected K20C1

The Details

Radium's rail taxonomy matters here: upgrade rails keep the OEM injector interface, while top feed conversion rails change injector styles, and this K-series rail is firmly the former, so injector changes must stay OEM-equivalent in height and O-ring dimensions, with flow rates chosen by your tuner and dimensions confirmed by the injector manufacturer. The rail-only kit suits custom plumbing; for the stock feed line, Radium's plumbing kit (20-0230-PK, sold separately) adds the extended SAE quick connect that clears the OEM coolant hose plus port plugs. Installation is documented down to the torque spec: OEM spacers position the assembly, and the included M8 hardware torques to 10 ft-lbs. Pre-lubricate every O-ring, prime with key cycles, and leak-check before and after first start.

Kit Includes

• 1x Black anodized, laser etched K-series fuel rail
• Stainless steel mounting hardware
• Phenolic thermal insulating washers
• Plumbing kit 20-0230-PK sold separately for factory feed line connection

Applications

• 2001-2005 Honda Civic Si (EP3) and 2002-2006 Acura RSX / RSX Type-S (K20)
• All K-series engines with port-injection OEM manifolds (K20/K24); K-swap applications
• NOT compatible with the direct-injected K20C1