Radium DMR User manual

1
1x DMR Assembly:
-Billet Aluminum Body
-Billet Aluminum Cap
-Orifice
-Spring Grounded
-Spring Hat
-Diaphragm
-Vacuum Barb
-Set Screw Stainless
-Jam Nut Stainless
-5 Cap Bolts Stainless
1x Fitting 6AN ORB Plug
1x Fitting 6AN Male
1x Interchangeable Orifices
1x Retaining Tab Stainless
2x Bolt Stainless
1x Adapter (varies with kit)
The DMR is a high flowing Radium Engineering fuel pressure regulator that mounts directly to a fuel rail. The fuel rail adapter
features a unique O-ring design that permits the entire unit to swivel when installed Port A). For ideal hose routing, either of the
two opposing 6AN ORB 9/16”-18 threaded) female ports B and C) can be used for the fuel return connection. The unused return
port should be plugged using the included fitting.
FITTINGS AND PORTS
A Pressure regulated inlet port from fuel rail, via adapter.
B Return outlet port, 6AN ORB 9/16"-18). Can be swapped with C.
C Return outlet port, 6AN ORB 9/16"-18). Can be swapped with B.
!!DO NOT INSTALL A PRESSURE GAUGE INTO PORTS B or C!!
These ports are for fuel return back to the fuel tank and not for pressure reading.
INSTALLATION INSTRUCTIONS
DIRECT MOUNT REGULATOR DMR)
Document# 19-0108
Support: [email protected]
WARNING! Exercise extreme CAUTION when working with fuel systems. Do not smoke or expose the
working area to any spark or flame. Work in a well-ventilated area. Clean up all spilled fuel immediately
and dispose cleaning materials in a sealed metal trash container. Relieve fuel pressure prior to working on
the fuel system. To prevent failure all O-ring fittings MUST be lubricated prior to assembly.

2
INSTALLATION
The DMR should be mounted on the fuel rail outlet. The DMR inlet adapter fitting must match the fuel rail outlet port. The adapter
by itself can be installed to the fuel rail first, or the complete assembly can be installed at once.
If installing into an ORB O-ring boss), make sure there is chamfer on the port for properly seating the O-ring. When installing an ORB
adapter, first lubricate the O-ring and then tighten it into port.
With the adapter installed in the fuel rail and the O-ring lubricated on the adapter, push the DMR onto the adapter until fully seated.
Slide the metal retaining bracket into place reference diagram on previous page). Next, line up the bracket to the 2 mounting holes.
Apply a medium strength thread-locker to the 2 included stainless steel bolts. Secure using a 2.5mm Allen wrench.
NOTE: Once installed, the DMR can be rotated in any direction
including upside down, if required.
PLUMBING
DO NOT plumb the fuel pump feed line into one of the DMR return ports B or C). The return line back to the fuel tank or surge
tank) can attach to either port B or C. Plug whichever port is not used. Do not install a pressure gauge into ports B or C.
VACUUM REFERENCE
The 3/16” 5mm) vacuum barb on the regulator is used if a 1:1 vacuum reference is required. This maintains a constant ratio
between fuel pressure and intake manifold pressure for consistent fuel delivery. If the OEM pressure regulator used a vacuum hose,
route this to the barb on the DMR 5/32” ID vacuum hose is recommended). NOTE: the billet cap can be clocked to point the barb
fitting in 5 different directions. See the servicing information below for more details.
INTERCHANGEABLE ORIFICE
The DMR is equipped with an interchangeable orifice inside the regulator. This part can be easily swapped out with a different size.
These orifices have different inside flow diameters. This is required in order to match the pump s) flow rate, fuel hose restrictions,
and targeted base static fuel pressure. The DMR comes preassembled with the “silver” orifice, which is a good match for most single
and dual pump systems. However, if multiple high flow pumps are used in a low static pressure system, the “gold” orifice can be
easily swapped in using common tools. See the servicing information below for more details.
Orifice Color
Manufacturer Rated Flow @ 43.5 psi
Silver
Factory Installed Up to 900 LPH total fuel pump flow
Gold
Up to
1500
LPH total
fuel pump
flow
*These recommendations are only general suggestions to get started. Backpressure
created by return line system, operating voltage and line pressure drop will have an
influence on the final static pressure and orifice selection.

3
PRESSURE SENSOR/GAUGE
The DMR is NOT equipped with a port for pressure reading. Do not connect a sensor or gauge to ports B or C. If a pressure sensor or
gauge is needed to monitor system pressure, it must be installed elsewhere in the system such as on the fuel rail or the feed line
leading to the fuel rail. Radium offers a variety of adapter fittings to accomplish this.
START UP
NOTE: The DMR is not pre-set to any particular pressure setting out of the box.
 Reconnect the battery.
 Turn the ignition to the ON position to allow the fuel pump to prime the system do not start the engine).
 Cycle the ignition power a few times and check for fuel leaks.
 If there are any leaks, they must be corrected before proceeding.
 Start the engine and recheck for leaks.
 Use a pressure gauge or sensor to adjust the fuel pressure according the procedure below.
FUEL PRESSURE ADJUSTMENT
The DMR can be fine-tuned for the specific application using a fuel pressure sensor or gauge mounted elsewhere in system).
Determine what the target static fuel pressure setting should be before beginning this procedure. This target setting can be different
for many vehicles. Consult with the EFI tuner, or match factory pressure setting specified by the manufacturer.
 To set static fuel pressure, disconnect the vacuum line from the DMR and temporarily plug the vacuum line to prevent a
leak. During this test, leave the DMR barb open to atmosphere to allow venting.
 Activate the fuel pump by starting the engine or manually powering the pump.
 Loosen the jam nut on the top of the DMR using a 3/8" wrench.
 Using a 3/32" Allen wrench
a) Tighten the set screw clockwise rotation) to increase fuel pressure.
b) Loosen the set screw counter-clockwise rotation) to decrease fuel pressure.
 Once the fuel pressure is set at the target, tighten the jam nut.
 Turn OFF the engine and secure the vacuum hose on the DMR.
SERVICING
 Relieve fuel pressure.
 Use a 5/64" Allen wrench to gradually remove the 5 screws using an alternating cross-pattern sequence.
 Inspect the diaphragm for excessive wear and possible leaking.
 For replacement parts, please contact Radium Engineering.
 To change the orifice, use a 7/16" socket wrench.
 Reference diagram for reassembly. The diaphragm and seating surfaces MUST be clean for proper sealing.
 BE CAREFUL TO NOT INSTALL THE SPRING HAT UPSIDE DOWN
 Clock the billet cap to point the vacuum barb as needed.
 Tighten the 5 screws gradually in an alternating cross-pattern sequence.