EVIL ENERGY Adjustable Fuel Pressure Regulator 6AN Bypass/Return — Black, 30–70 PSI with Gauge

The EVIL ENERGY Adjustable Fuel Pressure Regulator is a 6AN bypass/return regulator that lets you set and stabilize EFI fuel pressure between 30 and 70 PSI for gasoline, E85 and ethanol blends.

This billet-style regulator is designed to suit most electronic fuel injection (EFI) systems where a bypass or return-style setup is used. Finished in black, it includes a top-mounted adjustment screw and a pressure gauge so you can dial in the exact operating pressure. The kit arrives with multiple fittings, fuel line, mounting hardware and port plugs to help adapt the unit to different fuel-rail setups—but note it is not compatible with diesel systems and some braided lines may not support E85.

How do I adjust and read the fuel pressure on this regulator?

Pressure is set with the accessible adjustment screw on the regulator’s top; turning it clockwise or counterclockwise increases or decreases output. A threaded gauge port and included pressure gauge make it simple to monitor real-time pressure while the engine is running or during setup on a test bench.

• Adjustable range: 30–70 PSI for precise tuning.
• Top-mounted set screw for easy access without disassembly.
• Included pressure gauge screws into the NPT port—use thread sealant tape for a leak-free fit.
• Calibration can be verified under load to ensure stable EFI fuel delivery.

Which fuels and plumbing work with this EVIL ENERGY regulator?

This regulator accepts gasoline, E85 and alcohol/ethanol fuels but is not rated for diesel. Some nylon-braided fuel lines are incompatible with strong ethanol blends, so confirm line compatibility before installing with E85.

• Compatible fuels: gasoline, E85, alcohol/ethanol blends.
• Not for diesel use—use a diesel-specific regulator for diesel systems.
• Provided nylon outer-braid CPE fuel line may not be suitable for E85 long-term.
• Use thread sealant on the gauge NPT port to prevent leaks.

What fittings and parts come with the kit and how are they used?

The package contains a complete assortment to adapt the regulator to common EFI plumbing layouts, including AN fittings, port plugs, and a mounting bracket. Some supplied adapters are intended for fuel rail use only and should not be installed directly on the regulator to avoid leaks.

• Kit includes: regulator, pressure gauge, bracket, AN port plugs and multiple AN fittings.
• Four 6AN to 6AN ORB fittings and one 6AN ORB to 6AN barb fitting for common connections.
• Two 6AN-to-M fittings (6AN→M12x1.25 and 6AN→M14x1.5) are for fuel rail adapters only.
• Three sections of 6AN nylon outer-braid CPE fuel line for routing and assembly.

Who is this for? The EVIL ENERGY adjustable regulator is aimed at car builders, tuners and DIY mechanics who run aftermarket EFI systems, turbo or boosted applications, or who need precise fuel pressure control for engine tuning. It’s a practical choice when you require a return/bypass-style regulator with a wide adjustment window, included mounting hardware and fittings for flexible plumbing. If you run diesel or plan to rely on specific braided lines for long-term E85 service, verify compatibility or choose components rated for those fuels before installation.