Radium 20-0423 Fuel Rail Plumbing Kit for 1999-2005 Mazda Miata MX-5 NB

Vehicle Fitment

• 1999-2005 Mazda MX-5 Miata (NB - All Trims incl. Base, LS, SE, 10th Anniversary, Shinsen, Mazdaspeed - 1.8L DOHC BP Engine)

Fitment Notes

• This is a fuel rail plumbing add-on kit only - the Radium Engineering fuel rail (20-0369) is required and sold separately. This kit does NOT include the fuel rail itself.
• For the 1994-1997 NA Miata plumbing kit (different configuration - OEM FPR retained, feed and return hoses replaced), see Radium 20-0422.
• The OEM fuel pulse damper (FPD) and OEM fuel feed hose are retained in this installation - only the return side plumbing is replaced by the included fittings.
• If the vehicle is equipped with EGR, the EGR system must be removed to allow OEM fuel pulse damper fitment with this kit. Confirm EGR removal is permissible for your application before purchasing.
• Installation instructions are available at radiumauto.com.
• Sold as a complete plumbing kit - all listed fittings included.

Features

• Plug-and-play bolt-on installation - provides all fittings needed to connect the Radium Engineering fuel rail (20-0369) to the OEM 1999-2005 Miata fuel system without cutting, welding, or custom fabrication.
• Retains the OEM fuel pulse damper and OEM fuel feed hose, minimizing cost and complexity while maintaining the OEM's pulse damping function for fuel pressure stability.
• 8AN ORB to OEM FPD adapter fitting (20-0301) connects the Radium fuel rail's 8AN ORB port directly to the OEM fuel pulse damper - no pulse damper replacement required.
• 8AN ORB to 6AN male fitting (14-0151) and 6AN 90-degree female coupler (14-0268) provide a flexible, low-profile return line connection at the fuel rail outlet.
• SAE quick connect fitting (14-0146) mates to the OEM SAE fuel line connector for a factory-style, tool-free connection at the return side.
• 8AN ORB plug (14-0150) caps the unused fuel rail port for a clean, leak-free installation.
• All fittings are compatible with gasoline, E85, ethanol, and methanol fuel types.
• Manufactured in the USA by Radium Engineering.

Specifications

• Part Number: 20-0423
• Type: Fuel Rail Plumbing Add-On Kit
• Application: 1999-2005 Mazda MX-5 Miata (NB) - 1.8L DOHC BP Engine
• Compatible Fuel Rail: Radium 20-0369 (sold separately)
• OEM Components Retained: Fuel Pulse Damper, Fuel Feed Hose
• Fuel Rail Included: No
• EGR Note: EGR must be removed if equipped for OEM FPD fitment
• Fuel Compatibility: Gasoline, E85, Ethanol, Methanol
• Manufactured: USA
• Quantity: Sold as Complete Plumbing Kit
• Warranty: 1 Year Limited

Included Components

• 1x 8AN ORB to OEM Fuel Pulse Damper Adapter Fitting (Radium 20-0301)
• 1x 8AN ORB to 6AN Male Fitting (Radium 14-0151)
• 1x 6AN 90-Degree Female Coupler (Radium 14-0268)
• 1x SAE Quick Connect Fitting (Radium 14-0146)
• 1x 8AN ORB Plug Fitting (Radium 14-0150)

Product Description

The Radium Engineering 20-0423 is the fuel rail plumbing add-on kit for the 1999-2005 Mazda MX-5 Miata (NB), providing all fittings needed to connect the Radium Engineering 6063 aluminum fuel rail (20-0369, sold separately) to the NB Miata's OEM fuel system in a bolt-on, plug-and-play configuration. Unlike the 1994-1997 NA Miata kit (20-0422), which replaces the OEM fuel feed and return hoses entirely, the NB kit is designed to retain the OEM fuel pulse damper and the OEM fuel feed hose - only the return side plumbing is addressed by the included fittings. This approach minimizes the parts and cost required to integrate the Radium rail while preserving the OEM pulse damping function.

The included 8AN ORB to OEM FPD adapter fitting (20-0301) connects the Radium rail's 8AN ORB inlet port directly to the OEM fuel pulse damper. The 8AN ORB to 6AN male fitting (14-0151), 6AN 90-degree female coupler (14-0268), and SAE quick connect fitting (14-0146) handle the return path back to the OEM fuel line. The remaining 8AN ORB plug (14-0150) caps the unused port on the rail for a clean, leak-free finish. Note that if the vehicle is equipped with EGR, it must be removed to allow proper OEM fuel pulse damper fitment - confirm this is acceptable for your application before purchasing. Installation instructions are available at radiumauto.com. Fuel rail not included; manufactured in the USA.