BMW S54 Radium Fuel Rail The aluminum Radium Engineering fuel rail is machined and anodized for compatibility with all fuel types, including E85. Manufactured with a large internal bore. It is compatible with OEM and aftermarket injectors. It features a large 17.5 mm internal bore with -8AN ORB (3/4-16 O-ring) threaded ports at each end and a 3/8" NPT female center port to accommodate a variety of high-flow system adapters. It is compatible with all fuel types including popular alcohol blends like E85. The fuel rail is a direct bolt-on for all BMWs equipped with the S54 engine, including: 20012006 BMW M3 20012002 BMW Z3 M Coupe 20012002 BMW Z3 M Roadster 20062008 BMW Z4 M Coupe 20062008 BMW Z4 M Roadster 20022011 Weismann Roadster MF3 Quick Facts: CNC machined Black anodized Internal diameter of 17.5mm for high flow AN8 (3/4 UNF) threads on the ends Direct mount regulator can be installed with AN8 ORB or a pulse damper