Two parts in one! The Fuel Pressure Regulator Damper (FPR-D) is the ultimate solution for consolidating critical fuel system components into a single high-flow package. It is a fully functional high performance adjustable EFI fuel pressure regulator with a unique built-in fuel pulse damper. This universal product can be used with any EFI fuel system.

A fuel pulse damper is an excellent tool for smoothing out "noisy" fuel systems that are experiencing a lot of pulsing from the injectors opening/closing, and also from the fuel pump. Find out more about fuel pulse dampers HERE.

Now available with a green anodized adjustment knob.

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MOUNTING
This regulator features two M6x1mm threaded mounting holes in the body. A laser cut anodized aluminum mounting plate is provided with 4 countersink M6x1mm bolts/nuts.

The FPRD-RA can be mounted any direction including upside down.

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PLUMBING
The inlet (side) and outlet (bottom) feature large 10AN ORB (7/8'-14) threaded ports. Two -6AN and two -8AN male adapter fittings are included to suit most aftermarket fuel systems. 
The 1/8' NPT auxiliary port can be used for monitoring fuel pressure. The Radium fuel pressure gauge is commonly used. An included plug can be used if this port is not needed. 

NOTE: This regulator has a single inlet port and single outlet (return) port. Because of this, it cannot be used in a dead-head fuel system. It must be plumbed AFTER the fuel rail.  Check out the Multi-Port Regulator (MPR) for dead-head fuel plumbing. 

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FUEL PULSE DAMPER
The integrated fuel pulse damper stabilizes fuel pressure from pulses created by the fuel pump, fuel injectors, regulator, etc. The base pressure requirement for maximum damping efficiency is 40-105psi (2.8-7.2bar). This range is base static pressure only. For dynamic fuel pressure outside this range, the vacuum/boost reference line will be required for the damper portion, otherwise this vacuum reference is usually plugged.

NOTES:
1. Base pressure is measured with the fuel pump running without a vacuum line connected to the regulator.
2. This product is NOT FOR USE on the low pressure side of mechanical fuel pumps including direct injection HPFP.

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FUEL PRESSURE REGULATOR
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.

Fuel pressure is adjusted using the knob on the top of the regulator body. 

Minimum Pressure: 18.5psi (1.3bar)
Maximum Pressure: 100+ psi*
*This is rhetorical. The maximum pressure is dependent on the relief valve inside the pump or the maximum current the fuel pump controller allows. 

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ABOUT FUEL PRESSURE DROP AFTER SHUTOFF
Some installations may experience a rapid fall of fuel pressure when the engine and/or fuel pump shuts off. This is considered normal operation for aftermarket fuel pressure regulators, regardless of brand. 

This can occur due to the diaphragm seat and the return orifice not fully sealing when fuel flow is stopped. For regulators to have the ability to regulate high fuel flow rates, the size of these components must be increased. This creates larger sealing surfaces between the components, preventing them from forming a perfect seal, even with high spring rates. This is not an indication of an issue or defect and it is not a cause for concern on its own. You do NOT need to contact technical support about this issue. Fuel pressure will reset immediately when the fuel pump is activated again.

If the engine is experiencing other symptoms such as long cranking to start, or delays in pressure building when cranking, these symptoms are unrelated to the regulator. There is likely an issue with the fuel feed hose draining back to the tank. This is most likely due to an internal leak somewhere in the pump module, ie: a venturi jet pump, or the lack of a fuel pump check valve.

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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.

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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. 

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INCLUDED
-Main Rotating Assembly with Damper
-Mounting Bracket with M6x1mm Hardware
-5mm Barbed Vacuum Fitting (x2)
-Vacuum Plug Fitting, Returnless (x2)
-1/4' Push-To-Connect Fitting (x2)
-3AN Male Vacuum Fitting (x2)
-6AN male Adapter (x2)
-8AN male Adapter (x2)
-1/8' NPT Port Plug
-Vacuum Hose Y-adapter
-Vacuum Hose, 5/32' ID