EVIL ENERGY Fuel Pressure Regulator 6AN EFI Bypass/Return — Black, Adjustable 20–120 PSI with Gauge

EVIL ENERGY Adjustable EFI Fuel Pressure Regulator is a 6AN bypass/return regulator that lets you set fuel pressure between 20–75 PSI with the stock spring, or 75–120 PSI with the included replacement spring.

This compact, black-anodized regulator is built for gasoline, E85 and other alcohol-blend fuels (not diesel) and arrives with a pressure gauge, multiple ORB fittings, a replacement spring and installation accessories. Designed for retrofit or custom fuel systems, it converts a fixed-line feed into an adjustable bypass-return arrangement and gives tuners and mechanics fine control over fuel rail pressure for EFI engines.

How do I adjust and change the pressure range?

Adjustment is done with the access screw on the top of the regulator; turn clockwise to increase pressure and counterclockwise to lower it. The regulator ships with a pre-installed spring for 20–75 PSI; swap in the provided replacement spring for a higher 75–120 PSI range.

• Top-mounted set screw for on-car tuning without disassembly
• Pre-installed spring: 20–75 PSI; replacement spring: 75–120 PSI
• Use pressure gauge included to verify target PSI during setup
• Thread sealant tape supplied for gauge NPT port sealing

Which fuels and systems is this regulator compatible with?

The regulator is compatible with gasoline, E85 and most alcohol/ethanol blends; it is not suitable for diesel. Note that nylon-braided fuel lines may not be compatible with E85—choose compatible hoses for ethanol applications.

• Works with EFI systems using a bypass/return architecture
• Compatible fuels: gasoline, E85, alcohol/ethanol blends
• Not compatible with diesel fuel or incompatible nylon lines for E85
• Includes AN/ORB fittings to integrate with common aftermarket fuel plumbing

What hardware and fittings are included for installation?

The package is supplied ready for many custom installs: a pressure gauge, multiple AN-to-ORB fittings and a spare spring are included so you can adapt the regulator to different hose sizes and return ports. Also supplied are an AN10 port plug, an Allen key and thread sealant tape to help seal the gauge port.

• 1x pressure gauge and 1x replacement spring in the box
• Fittings: AN6 to AN6 ORB, 2x AN6 to AN10 ORB, 2x AN8 to AN10 ORB, 2x AN10 to AN10 ORB
• AN10 port plug, Allen key, and sealant tape included
• Professional installation recommended for safe, leak-free results

What installation and safety points should I be aware of?

Always use the supplied thread sealant tape on the NPT gauge port and check all ORB/AN fittings for proper sealing. Because fuel systems are pressurized and involve flammable liquids, professional installation or experienced DIY with proper tools is strongly recommended.

• Apply thread sealant tape on gauge NPT port before fitting
• Verify hose and fittings are compatible with chosen fuel (E85 considerations)
• Bleed and test system carefully at low pressure before full operation
• Inspect for leaks after initial start-up and during first road tests

Who is this for: EVIL ENERGY’s adjustable fuel pressure regulator is aimed at engine builders, tuners and enthusiasts fitting or upgrading EFI fuel systems who need precise rail pressure control. It fits custom or retrofit fuel rails on street or race applications using gasoline or ethanol blends, and is useful where variable fuel pressure helps match injectors, pumps and ECU tuning strategies.