Fits 99-05 Mazda MX-5 Miata

This system is suitable with all gasoline types including unleaded, leaded, oxygenated, and pre-mixes. It is also compatible with alcohol blends of fuel including methanol, ethanol, and E85. 

This kit features a new adjustable fuel pressure regulator (FPR) that is compatible with all fuel pump hangers including the factory returnless system found in the NB chassis. As shown below, the FPR is mounted near the EVAP charcoal canister using OEM threaded studs.

The OEM fuel feed line from the fuel pump to the fuel filter is reused and unaltered. However, two new 6AN fuel lines are provided to and from the FPR.

A fuel pressure gauge mounts adjacent to the FPR on the feed line for easy adjustment. A stainless steel SAE quick connect plug is provided to block off the "TEE" on the OEM feed line.

1:1 RISING RATE VACUUM REFERENCE

The RA-series regulator features a 360 degree swiveling vacuum reference port that is double O-ring sealed. This is the first in the industry. It permits the installer to quickly point the vacuum fitting in any direction with no tools required.

There are 4 interchangeable 10-32 threaded vacuum port fittings provided to cover all scenarios:

• Barbed Fitting: A black zinc-plated 3/16" (5mm) barb machined from high strength steel that is compatible with the following vacuum hoses: 5/32" (4mm), 3/16" (5mm), and 7/32" (6mm)
• 3AN Male Fitting: A black zinc-plated adapter machined from high strength steel that is compatible with 3AN hose ends
• Push-To-Connect: A nickel-plated brass fitting with Buna-N O-rings that is compatible with hard plastic 1/4" OD tubing
• Vacuum Plug: A black oxide stainless steel screw that is used to maintain a constant (non dynamic) fuel pressure. To keep fuel pressure the same as the OEM MX-5 fuel system, this plug should be used

NOTE: When installing the vacuum fitting, it is recommended to use a wicking medium-strength threadlocker.

ABOUT FUEL PRESSURE DROP AFTER SHUTOFF

Some installations may experience a rapid fall of fuel pressure when the engine and/or fuel pump shuts off. This is considered normal operation for aftermarket fuel pressure regulators, regardless of brand. 

This can occur due to the diaphragm seat and the return orifice not fully sealing when fuel flow is stopped. For regulators to have the ability to regulate high fuel flow rates, the size of these components must be increased. This creates larger sealing surfaces between the components, preventing them from forming a perfect seal, even with high spring rates. This is not an indication of an issue or defect and it is not a cause for concern on its own.

You do NOT need to contact technical support about this issue.

Fuel pressure will reset immediately when the fuel pump is activated again.

If the engine is experiencing other symptoms such as long cranking to start, or delays in pressure building when cranking, these symptoms are unrelated to the regulator. There is likely an issue with the fuel feed hose draining back to the tank. This is most likely due to an internal leak somewhere in the pump module: possibly a venturi jet pump, or the lack of a fuel pump check valve.

• No permanent modifications are required
• Compatible with Radium Engineering 20-1020 Mazda MX-5 Fuel Hanger
• Compatible with OEM fuel hanger (instructions detail how to bypass the OEM FPR)

• MPR-RA Fuel Pressure Regulator
• Fuel Pressure Gauge, 0-100psi
• Stainless Steel Mounting Bracket
• Anodized Aluminum Fittings
• SAE Quick Connect Fittings
• Hose Clamps and Hardware
• 6AN (3/8") Fuel Hose