Radium MPR Fuel Pressure Regulator

The Radium Multi Pump Regulator (MPR) is manufactured in the USA and is the ultimate solution for simple or complex high-flow fuel systems. Its unique port configuration make it ideal for combining multiple fuel pumps into a single feed line or vice versa. The MPR can be plumbed many different ways to suit most any installation; traditional flow-through or dead-end systems. Because of this flexibility, it is also perfect for Radium fuel surge tanks by eliminating the need for an extra "Y" fitting.

The lower two opposing return ports are unique in that they flow parallel with the pressure ports eliminating the need for elbow fittings.  Flexible mounting options include wall mounting using the M6 holes that pass through the regulator body, or the included mounting bracket (shown below) can be used for floor mounting. M6x1mm hardware is provided.

The regulator can be plumbed many different ways to suit various installations, such as traditional flow-through or dead-head systems. Because of this flexibility, it eliminates the need for an extra "Y" fitting. The lower 2 opposing return ports are unique in that they flow parallel with the pressure ports eliminating the need for elbow fittings. Either lower port can be used for the return line. Plug(s) are provided for unused ports. 

Fuel pressure is dialed in using the preload set screw on top. The 1:1 vacuum reference high flow design has been tested to regulate over 1,400 liters per hour (see MORE DETAILS tab). Furthermore, with the addition of interchangeable return orifices, the MPR can be used in ANY horsepower output EFI system imaginable and is compatible with all gasoline and ethanol blends of fuel. To aid in adjusting pressure, there are incremental detents that provide haptic feedback to the user. Every detent permits 1psi (+/-0.5psi) of adjustment depending on current fuel pressure.

Radium's RA-series regulators feature 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:

1. 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).
2. 3AN Male Fitting: A black zinc-plated adapter machined from high strength steel that is compatible with 3AN hose ends.
3. Push-To-Connect: A nickel-plated brass fitting with Buna-N O-rings that is compatible with hard plastic 1/4" OD tubing.
4. Vacuum Plug: A black oxide stainless steel screw that is used to maintain a constant (non dynamic) fuel pressure. Beginning in the mid 1990s, vehicle manufacturers started transitioning to returnless fuel systems to lower EVAP emissions. To keep temperatures lower, these regulators are mounted inside the tank and do NOT have the ability to be vacuum referenced. This plug would be required in this scenario.

The Radium MPR is suitable with all gasoline types including unleaded, leaded, oxygenated, and pre-mixes, plus alcohol blends of fuel including methanol, ethanol, and E85. 

Note that this regulator is intended to be used with a full aftermarket fuel system using AN fittings and lines. This regulator is in no way compatible with a stock Subaru fuel system. For this reason this website's fitment indicator will NOT indicate it will fit on your car -- because unless your fuel system is totally custom, it won't.

Installation instructions

Includes 

• Multi-pump regulator
• Mounting bracket with hardware
• Three interchangeable orifices
• 5mm barbed vacuum fitting
• 1/4" push-to-connect vacuum fitting
• 9/16"-18 (-6AN) O-ring port plug (x2)
• 3/4"-16 (-8AN) O-ring port plug (x1)
• 6AN male adapter fitting (x3)
• 8AN male adapter fitting (x1)

 Black in color.