New Product: Adjustable Fuel Pressure Regulator

Radium Engineering is proud to announce an all new universal adjustable fuel pressure regulator (AFPR) for high performance vehicles.


The AFPR is CNC machined aluminum which is anodized black and laser engraved. Instead of tapered pipe threads, the unit design includes 5 ports that are O-ring sealed.

So why another regulator?  With all of the universal FPRs on the market, we could not find one that installed seamlessly into multiple pump fuel systems. To solve the problem, installers were left with a choice of using Y-blocks and other awkward T-fittings for proper plumbing. So we decided to create a solution with a new high flow regulator, keeping in mind the needs of our fuel surge tank customers. Lets take a closer look at the AFPR and see why it is the best choice for difficult fuel plumbing situations.



The arrangement of the AFPR ports are different than any other regulator. Every FPR on the market directs the return port downwards out the bottom of the unit. This makes it limited to wall mounting and difficult to nearly impossible to mount the FPR to a floor. Furthermore, the return port requires a 90 degree elbow which are expensive and not always available with a swivel option. We took this port and converted it into a "return chamber" (bottom port shown above) that runs in-line with the high pressure ports. The chamber is threaded at each end for 9/16"-18 (-6AN). This allows the regulator to be easily floor mounted, such as in a trunk near a surge tank, without any 90 degree hose-end fittings. The installer can choose to connect the return line to either end of the return chamber making the AFPR suitable for their installation. Unless there is a need to use two -6AN return hoses, the opposite end is blocked off using the included plug(s).



Here is a cut-away (fittings installed in all ports) showing the return chamber. Bypassed fuel comes down the center of the body into the fuel return chamber then exits through the return port(s).


The high pressure ports on the AFPR are also unique. Most regulators have single ports on opposing sides. This is not always helpful when working with multiple fuel pump lines. The Radium AFPR is configured with 3 high pressure ports; two 9/16"-18 (-6AN) and one 3/4"-16 (-8AN). Shown in the picture above is the -8AN (top port).


On the opposite side, there are two -6AN pressure ports (shown above). This design makes plumbing two fuel pumps easy and eliminates the need for an expensive Y-block fitting. Each pump can feed into one of the -6AN pressure ports. The -8AN port on the opposing side is then used to route fuel to the rail(s). This is an excellent way to construct a robust dead-end fuel system which is ideal to keep fuel temperatures low. The AFPR can also be easily used as a traditional return-style regulator. Please visit the product page to find additional information on plumbing the AFPR.

On most other aftermarket FPRs, there is a 1/8" NPT port on the front of the unit. When not using this for a transducer, gauge, sensor, etc. it has to be plugged with pipe tape or paste. Often times there is no room for these ancillary components as the entire unit as a whole becomes too big and causes interference with nearby objects, such as an intake manifold. Furthermore, in cases such as a returnless system, the pressure reading should be taken at the fuel rail for accuracy. The AFPR does away with an integrated pipe fitting. Instead, if the -8AN port is not used and the AFPR is mounted near the fuel rail, Radium offers a special billet 1/8" NPT adapter fitting (shown in green) to connect gauges, sensors, transducers, etc.

Furthermore, when this port is used, the component sits inline with the hoses making it less prone to object interference.


The AFPR also features a unique interchangeable return port that accepts 3 different ID orifices. This allows 1 regulator to work with a wide range of fuel systems. The AFPR has been tested using ranges from low flow OEM pumps to multiple fuel pumps delivering over 1400LPH of fuel flow. This means the AFPR can be used in virtually any fuel injection application. All that is required is a simple swap of the included orifices (0.10in, 0.18in, 0.25in).

Shown in the graph above is the minimum fuel pressure the regulator can provide as a function of pump flow rate.


For fine-tuning fuel pressure, a stainless steel set screw and jam nut is used. The OEM quality diaphragm changes fuel pressure at a 1:1 ratio when the 5mm barb is connected to a vacuum source.


The included powder coated bracket can be used to mount the AFPR to a floor or other flat surface. For wall mounting, simply secure the AFPR using the 2 through-holes in the regulator body and long M6 stainless steel bolts (the bracket is not required). Also, when wall mounting the AFPR, it can be flipped 180 degrees to suit the direction of which side the -8AN and two -6AN ports are pointed.

Like all Radium Engineering products, the AFPR is made in the USA and carries a lifetime warranty. For more information, please visit the AFPR product page in the Radium online store.

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