Radium Engineering DMR Direct Mount Regulator Green

The Radium Direct Mount Regulator (DMR) fuel pressure regulator is an adjustable, compact, and high-performance EFI fuel pressure regulator capable of managing high-flow fuel systems. Its compact design allows for installation in tight spaces without compromising performance.
MOUNTING

The DMR is designed with a unique and highly versatile mounting system. It can be mounted directly to an 8AN ORB fuel rail using the included 360-degree swivel adapter. If your fuel rail does not have an 8AN ORB port, Radium Engineering offers fuel rails for a wide variety of engines, all with 8AN ORB ports (an adapter for 10AN ORB fuel rail ports is also available). Alternatively, the DMR can be mounted off-rail using the 20-0624 remote mount kit.

Its compact size allows it to be installed in areas with limited space without sacrificing performance.
CONNECTIONS

The main inlet port of the regulator has female threads for 6AN ORB. A dual-ended swivel adapter is included, allowing the regulator to be used on any compatible 8AN ORB fuel rail port, such as those on Radium Engineering fuel rails. Other swivel adapters are available but sold separately.
If the regulator is mounted off-rail, other adapters can be screwed into this port (sold separately).
The lower return port has 6AN ORB threads. The included 90-degree 6AN male fuel return fitting can swivel 360 degrees, allowing for multiple mounting configurations. Other adapters can be installed into the return port if needed (sold separately).

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

FUEL PRESSURE ADJUSTMENT

RA series regulators incorporate the first tool-free pressure adjustment. No longer are a locknut or adjustment screw required. With a simple twist of the knob, pressure is increased or decreased. Furthermore, there are no inherent air (vacuum/pressure) leaks through the threads that a smoke detector would traditionally detect.

Barb Fitting: A 3/16" (5mm) black zinc-plated barb fitting, machined from high-strength steel, 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, compatible with 3AN hose ends.

Push-to-Connect: A nickel-plated brass fitting with Buna-N O-rings, compatible with 1/4" OD rigid plastic tubing.

Vacuum Plug: A black oxide stainless steel screw used to maintain constant (non-dynamic) fuel pressure. In the mid-1990s, vehicle manufacturers began transitioning to returnless fuel systems to reduce EVAP system emissions. To keep temperatures low, these regulators are mounted inside the tank and do NOT allow vacuum referencing. In this case, this plug would be required.

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

FUEL PRESSURE STABILITY

After years of track and dyno testing, RA series regulators have been refined to optimize pressure management. A new unique stainless steel return orifice creates laminar flow, improving stability control.

Minimum Pressure: 18.5 psi (1.3 bar)

Maximum Pressure: *N/A

*This is rhetorical. The maximum pressure depends on the relief valve within the pump or the maximum current allowed by the fuel pump controller.

ABOUT FUEL PRESSURE DROPOFF AFTER SHUTDOWN

Some installations may experience a rapid drop in fuel pressure when the engine or fuel pump is turned off. This is considered normal operation for aftermarket fuel pressure regulators, regardless of brand. This can occur because the diaphragm seat and return orifice do not fully seal when fuel flow is interrupted. For regulators to regulate high fuel flow rates, these components must be increased in size. This creates larger sealing surfaces between the components, preventing them from forming a perfect seal, even with high spring rates. This does not indicate a problem or defect, and is not a cause for concern in itself. Technical support does not need to be contacted for this issue. Fuel pressure will immediately reset upon re-activating the fuel pump.

If the engine exhibits other symptoms, such as extended cranking or delayed pressure build-up during start, these symptoms are not related to the regulator. There is likely an issue with the fuel feed hose returning to the tank. This is probably due to an internal leak somewhere in the pump module, for example, in a Venturi jet pump, or the lack of a check valve in the fuel pump.
1:1 RISING RATE VACUUM REFERENCE

RA series regulators feature a 360-degree rotating vacuum reference port with a dual O-ring seal. This is an industry first, allowing the installer to quickly orient the vacuum connection in any direction without tools.

4 interchangeable 10-32 threaded vacuum port fittings are included to cover all needs.

Barb fitting: A 3/16" (5mm) black zinc-plated barb fitting, machined from high-strength steel, 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, compatible with 3AN hose ends. Push-to-Connect: A nickel-plated brass fitting with Buna-N O-rings, compatible with 6mm (1/4") OD rigid plastic tubing.
Vacuum Plug: A black oxide stainless steel screw used to maintain constant (non-dynamic) fuel pressure. In the mid-1990s, vehicle manufacturers began adopting returnless fuel systems to reduce evaporative (EVAP) emissions. To keep temperatures low, these regulators are mounted inside the tank and do NOT allow vacuum referencing. This plug is necessary in this case.

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

FUEL COMPATIBILITY

All RA series regulators are compatible with all types of gasoline, including unleaded, leaded, oxygenated, and pre-mix. Additionally, they are compatible with alcohol fuel blends, such as methanol, ethanol, and E85.

INCLUDES

Main swivel assembly
5mm barb vacuum fitting
Vacuum plug fitting (returnless)
1/4" easy connect vacuum fitting

3AN male vacuum fitting

6AN male swivel fitting (for return line)

Swivel inlet fitting (for 8AN ORB fuel rail)
PTFE impregnated 1/8" NPT plugs (x2)

Instruction PDF