Radium Engineering Direct Mount Regulator

Installation Instructions

RELEASED 9.11.23
The Radium Direct Mount Regulator-Rotating Assembly (DMR-RA) is a compact high performance adjustable EFI fuel pressure regulator.

MOUNTING

This regulator is designed with a unique highly versatile mounting system. It can be mounted directly to a compatible fuel rail port using the included 360 degree swiveling adapter, or mounted remotely away from the fuel rail (using Remote Mount Adapter Kit).

The compact size fits in areas with limited space, without sacrificing performance.

PLUMBING

The main inlet port on the regulator is female threaded for 6AN ORB. A swiveling double ended adapter (shown below) is included which allows the regulator to be used in any compatible 8AN ORB fuel rail port, such as those found Radium Engineering fuel rails. Other swivel adapters are available but sold separately. 

If mounting the regulator off-rail, other adapters can be screwed into this regulator port (sold separately HERE).

The bottom return port is threaded for 6AN ORB. The provided 90 degree 6AN male fuel return fitting can swivel 360 degrees, permitting a multitude of mounting configurations. Other adapter fittings can be installed in the return port if needed (sold separately).

This regulator has two 1/8" NPT side port locations that can be used with a pressure gauge, transducer, temperature probe, etc. Two 1/8" NPT plugs are provided.

FUEL PRESSURE ADJUSTMENT

RA-series regulators feature the first tool-less pressure adjustment. A jam nut and set screw are no longer required. With a simple turn of the knob, pressure will be increased or decreased. 

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.

FUEL PRESSURE STABILITY

With years of track and bench testing data, the RA-series regulators have been refined to optimize pressure management. A newly designed single stainless steel return orifice generates laminar flow that enhances stability control.

Minimum Pressure: 18.5psi (1.3bar)
Maximum Pressure: *N/A
*This is rhetorical. The maximum pressure is dependent on the relief valve inside the pump or the maximum current the fuel pump controller allows. 

1:1 RISING RATE VACUUM REFERENCE

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.

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

FUEL COMPATIBILITY

All RA-series regulators are suitable with all gasoline types including unleaded, leaded, oxygenated, and pre-mixes. Furthermore, they are compatible with alcohol blends of fuel including methanol, ethanol, and E85. 

INCLUDED

-Main Rotating Assembly
-5mm Barbed Vacuum Fitting
-Vacuum Plug Fitting (Returnless)
-1/4" Push-To-Connect Vacuum Fitting
-3AN Male Vacuum Fitting
-6AN Male Swivel (for Return Line)
-Swiveling Inlet Fitting (for 8AN ORB Fuel Rail)
-PTFE Impregenated 1/8" NPT Plugs (x2)