Radium Engineering Parts for Subaru WRX and STI

Top feed fuel rails: top feed conversion rails replace the restrictive factory side-feed system with high-flow rails featuring a 17.5mm internal bore, enabling compatibility with modern high-performance injectors. Versions are listed for EJ20 V1-V2, EJ20 V3-V6, EJ20/EJ25 conversion and top port upgrade fitments, plus EZ30/EZ36 Phase-I and Phase-II, SVX EG33 and Impreza EJ22/EJ251 applications.

Plumbing and pump hangers: parallel and series fuel rail plumbing kits supply the PTFE hose, fittings and filtration needed for a complete return-style fuel system. Fuel plumbing kits and fuel pump hangers are listed for WRX/STI GC/GD and GR/GV/VA chassis, along with fuel filter mounts, fuel line retaining kits and an RA-Series FPR kit with tool-less adjustment.

Injector fitment hardware: 22mm injector seats for EJ257, 26mm seats for SVX EG33, 14mm to 17mm injector seat adapters, air assist injector seats, fuel rail adapters and EJ20/EJ25 intake manifold gaskets.

Fluid Lock catch cans: dual, PCV and CCV catch can kits for the WRX VB, plus kits for the Toyota 86 / GR86 and Subaru BRZ (ZN6 / ZC6 / ZN8 / ZD8). The direct-injection turbo FA engines are known for blow-by related carbon buildup on the intake valves, and a closed-loop catch can system intercepts oil vapour before it reaches the intake tract. Radium's WRX-specific kits mount using factory holes with no cutting or drilling required.

Browse the wider Radium Engineering range, or see Radium Engineering Parts for Nissan and Radium Engineering Parts for Toyota GR Yaris and GR Corolla. Every brand we stock is listed on our brands page.

Radium fitment is defined by engine code and chassis code, so confirm both before ordering. EJ20 rail options are split by V1-V2 and V3-V6 fitment, while EJ20/EJ25 listings cover conversion, top feed upgrade and top port upgrade styles. Injector seats are sized by bore: 22mm for EJ257, 26mm for SVX EG33, with 14mm to 17mm adapters available for EJ20/EJ25.

Fuel plumbing kits, fuel pump hangers, fuel filter mounts and the RA-Series FPR kit are listed by chassis code — GC/GD, GR/GV/VA and the later WRX VA and VB. Catch can kits are chassis-specific as well, with separate WRX VB kits and Toyota 86 / GR86 / Subaru BRZ kits for ZN6 / ZC6 and ZN8 / ZD8. Fuel rail plumbing kits are offered in parallel and series configurations, so choose the layout that suits your fuel system design and power target.

Installation by a professional workshop is strongly recommended. Fuel system work involves depressurising the fuel system, safe handling of petrol and E85, and correct torquing and sealing of AN fittings, injector seats and O-rings, and it should be followed by a careful leak check before the vehicle is driven.

Depending on the parts you choose you may also need an EJ20/EJ25 intake manifold gasket, correctly sized injector seats or adapters, a fuel filter mount and filter element, and in-tank pump hardware to suit a single or dual pump configuration. Larger injectors and any change to fuel pressure or fuel type will require the ECU to be retuned by a qualified tuner.

Do Radium top feed conversion rails suit factory side-feed EJ engines?
Yes. The top feed conversion rails replace the restrictive factory side-feed system with high-flow rails using a 17.5mm internal bore, allowing modern high-performance top feed injectors to be used.

Are Radium parts compatible with E85?
Yes. The Radium Engineering components sold at Chicane Australia are compatible with E85 and race fuels.

What is the difference between the parallel and series fuel rail plumbing kits?
They differ in how fuel is routed between the two rails. Both kits include the PTFE hose, fittings and filtration required for a complete return-style fuel system.

Do the WRX catch can kits require drilling?
No. Radium's WRX-specific catch can kits mount using factory holes, with no cutting or drilling required.