Radium 8AN ORB Direct Mount Fuel Pressure Regulator (Green)
The Radium Engineering Direct Mount Regulator (DMR) is a compact high performance adjustable fuel pressure regulator that is capable of managing high flow fuel systems. It's compact package fits in tight spaces but does not compromise on performance.
The main inlet port on the regulator is female threaded for 6AN ORB. A swiveling double ended adapter (see photos) 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.
The bottom return port is threaded for 6AN ORB. The provided 90-degree 6AN ORB to 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).
The regulator has two 1/8' NPT side port locations that can be used with a pressure gauge (such as the Radium fuel pressure gauge), transducer, temperature probe, etc. Two 1/8' NPT plugs are provided so you can plug these if not used.
Fuel Compatibility:
This Radium regulator is 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.
How to adjust fuel pressure with this regulator:
Radium fuel pressure 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. Additionally, there are no inherent air (vacuum/boost) leaks through the threads that traditionally a smoke detector would pick up.
1:1 Rising rate vacuum reference:
Radium 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.
- 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
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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 thread locker.
Fuel pressure stability:
With years of track and bench testing data, the Radium 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.
Included:
- Main Fuel Pressure Regulator Assembly
- 5mm Barbed Vacuum Fitting
- Vacuum Plug Fitting (for returnless style systems)
- 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 Impregnated 1/8' NPT Plugs (x2)
Photo showing regulator installed at end of Radium rail:

All products sold by HA Motorsports include a no hassle 1 year VIP warranty against ANY manufacturing defects. We are proud to honor this warranty as we feel 100% confident in our products to perform flawlessly as intended and your complete satisfaction. Upon the occasion that a product of ours fails at any time within 1 year of purchase due to any manufacturing defects, your product will need to be returned to us for inspection to determine the cause of the failure and inspection for repair or replacement. Your 100% satisfaction is our goal and if you are not completely happy we'd like every chance to make it right.
What is covered under warranty:
- ECU board failure due to faulty ECU components (ie: injector driver fails, CPU processor fails, specific ECU circuit does not operate as intended, poor soldering, etc.)
- ECU component/hardware failure due to faulty manufacturing.
- Wire harness failure due to incorrect construction.
- Product failure due to a manufacturing or assembly problem.
- Outside company products. We will handle the hassle of shipping your product back to the manufacturer for warranty processing. Let us replace your product for you and we will deal with the warranty process with the manufacturer later.
What is NOT covered under warranty:
- ECU failure due to improper vehicle wiring (ie: ECU component fries due to sensors being connected incorrectly, low resistance fuel injectors being used without a resistor box, ROM chip being installed backwards by user, customer attempts to modify ECU in ANY way other than intended, etc.)
- Product being used in a way other than the intended use.
- Rear "warranty void if removed" sticker on ECU has been removed or altered.
- Failed, shorted, or corroded ECU board due to water damage.
- Any and all outside labor charges associated with removing and replacing product or diagnosing product failure.
- Wire harness failure due to improper use or rough handling.
- Cosmetic variances from manufacturing (ie: ECU lid has variation in powder coat texture or color within acceptable limits, wire harness color variations within acceptable limits).
How the warranty process works:
If you've determined that a product has failed due to a manufacturing defect, please contact us via email at sales@hamotorsports.com to review the symptoms you are experiencing to allow us to assist you with troubleshooting before shipping your product back to us for warranty. Many times, we can help you with the problem and determine what is being done incorrectly or how to configure the product properly to restore correct operation. If after we discuss the issues you are experiencing we determine that your product may need warranty replacement or inspection we will instruct you how to return it to us. Please note that we test EVERY ECU, EVERY ECU package, and wire harness components on our state-of-the-art testing equipment for complete proper operation before packaging and shipping to customers. PLEASE verify ALL wiring, installation, software settings, etc. are correct BEFORE contacting us for warranty repair/replacement.