Radium Engineering FPR Kit RA-Series – 99–05 Mazda MX-5

This Radium Engineering fuel pressure regulator kit is designed for Mazda MX-5 NB models using the factory returnless fuel system. It provides precise fuel pressure control for modified setups and is compatible with both OEM and Radium fuel pump hangers.

Adjustable 1:1 FPR Conversion – Compatible with Returnless Fuel Systems

Vehicle Compatibility:

• 1999–2005 Mazda MX-5 Miata (NB)

Overview:
This bolt-on kit replaces the factory non-adjustable system with a fully adjustable 1:1 rising rate fuel pressure regulator (FPR). It mounts near the OEM EVAP charcoal canister using factory threaded studs and connects via included -6AN fuel lines. A stainless steel quick connect plug is included to bypass the OEM fuel line "TEE." No permanent modifications are required.

Vacuum Reference Port Options (All Included):

• 3/16" (5mm) barb fitting

• 3AN male fitting

• 1/4" push-to-connect for hard plastic tubing

• Vacuum plug (for static pressure setup)

The RA-series regulator features a 360° swiveling vacuum reference port with a double O-ring seal—allowing flexible hose routing without tools.

Fuel Compatibility:

• Unleaded, leaded, oxygenated fuels

• Alcohol-based fuels including methanol, ethanol, and E85

Key Features:

• Adjustable fuel pressure for tuning and reliability

• Supports high-flow fuel systems

• Bolt-on installation using factory studs

• Compatible with OEM and Radium fuel pump hangers

• No cutting, drilling, or permanent modifications required