EVIL ENERGY Adjustable EFI Fuel Pressure Regulator 30–140 PSI – Red Anodized, AN10 Return with Gauge and Fittings

EVIL ENERGY’s adjustable EFI fuel pressure regulator is a billet 6061-T6 aluminum unit that lets you set and maintain fuel pressure between 30–140 PSI for gasoline, E85 and ethanol applications (not for diesel).

This compact, red-anodized regulator is built for engine tuning and reliable EFI performance. It arrives with a pressure gauge, a preinstalled spring for 30–80 PSI, a replacement spring for 80–140 PSI, multiple AN fittings and a return bypass, so you can tailor fuel pressure for street, race, or modified engines. The unit includes a vacuum/NPT port for fine control and an ORB-style AN10 return port for high-flow setups.

How do I change and set the fuel pressure on this regulator?

Adjusting pressure is done by turning the top set screw; the preinstalled spring covers 30–80 PSI and swapping in the included spring raises the range to 80–140 PSI. Always install the pressure gauge into the NPT port with thread sealant, and make small adjustments while monitoring fuel rail pressure under running conditions.

• Use the supplied allen key to turn the set screw for coarse adjustments.
• Fit the pressure gauge into the 1/8" NPT instrument port and seal with tape provided.
• Swap springs to switch between the low and high pressure ranges.
• Verify pressure on a warm engine under expected load before final tuning.

What fittings and ports are included for plumbing the return-style regulator?

The regulator features two 10AN (ORB) feed ports and one 10AN ORB return port, plus assorted AN adapters in three sizes supplied in the package. That assortment lets you adapt the regulator to prevailing line sizes or hose ends used in your vehicle’s fuel system.

• Three AN10-to-AN6 adapters for smaller feed lines.
• Three AN10-to-AN8 adapters to match common EFI plumbing.
• Three AN10-to-AN10 adapters for direct ORB-to-AN connections.
• One AN10 ORB port plug included for temporary sealing or testing.

Is this regulator compatible with my fuel and EFI system?

It’s compatible with gasoline, E85 and other alcohol-based fuels but not designed for diesel. The regulator is intended for electronic fuel injection systems that use a return-style setup; nylon braided lines are not recommended with E85.

• Works with most return-style EFI systems and aftermarket fuel rails.
• Not suitable for diesel or systems requiring specialized materials.
• Avoid nylon braided hoses when running alcohol fuels like E85.
• Professional installation is recommended for safe, leak-free operation.

What installation and maintenance steps should I follow?

Mount the regulator securely and use thread sealant tape on the gauge NPT port as supplied. Periodically inspect fittings for leaks and ensure the vacuum line (if used) is connected cleanly; replace seals or O-rings if you notice seepage.

• Apply the included sealant tape to the pressure gauge threads before installation.
• Torque AN fittings to manufacturer specs to avoid thread damage or leaks.
• Check the replacement spring and gauge function during initial break-in runs.
• Have a trained technician perform installation when in doubt.

Who is this for: EVIL ENERGY’s regulator is aimed at tuners, track drivers and performance-minded streetcar owners who need precise fuel pressure control for modified engines or when switching between fuel types like gasoline and E85. It’s also useful for engine builders and shops that install aftermarket EFI components and require a robust, tunable regulator with multiple plumbing options. If you want a durable, billet aluminum regulator with a broad adjustable range and included gauge and fittings, this unit is a practical choice.