EVIL ENERGY Fuel Pressure Regulator 30–140 PSI Adjustable Red — AN10 Return with Gauge

This precision fuel pressure regulator is built for tuned and stock electronic fuel-injected engines that require a reliable, adjustable supply pressure. Machined from 6061-T6 aluminum and finished in red, the regulator includes a gauge, pre-installed and replacement springs to cover two pressure bands, and a full set of AN fittings so you can integrate it into most EFI systems. The unit accepts vacuum reference and an instrument port for diagnostics, and it uses ORB-style AN10 ports for feed and return plumbing.

How do I change and set the fuel pressure?

Adjusting pressure is done with the top set screw and by swapping the internal spring. The pre-installed spring provides a 30–80 PSI range; swap to the included replacement spring for an 80–140 PSI range. Always initial-set with a fuel pressure gauge and fine-tune under operating conditions.

• Turn clockwise to increase pressure, counterclockwise to decrease.
• Use the supplied pressure gauge at the 1/8" NPT instrument port for readings.
• Swap springs for the higher 80–140 PSI band if needed.

Which fuels and engine systems is it compatible with?

The regulator works with gasoline, E85 and other alcohol-based fuels used in EFI systems but is not rated for diesel. Note that nylon braided hoses are not compatible with E85 — use fuel-rated lines approved for ethanol blends. This unit is intended for return-style EFI set-ups that can utilize an AN10 return port.

• Compatible: gasoline, E85, alcohol/ethanol blends.
• Not compatible: diesel fuel and nylon braided E85 lines.
• Designed for return-style electronic fuel injection systems.

What fittings and hardware are included for installation?

The package ships with the regulator, a pressure gauge, an extra spring, an ORB plug and a selection of AN adapter fittings to match different feed sizes. Also included are an Allen key and sealant tape to help seal the NPT gauge port during installation. These accessories simplify plumbing the regulator to most aftermarket fuel rails or pump setups.

• Included: pressure gauge, replacement spring, AN10 ORB plug.
• Adapters: three AN10-to-AN6, three AN10-to-AN8, three AN10-to-AN10 fittings.
• Tools/supplies: Allen key and thread sealant tape for gauge port.

How should this be installed and maintained for best results?

Professional installation is recommended to ensure correct plumbing and sealing, especially when working with pressurized fuel lines. Use thread sealant on the NPT gauge port, check all ORB fittings for proper torque, and test under idle and load to confirm stable pressure. Regular inspections for leaks and hose compatibility with ethanol fuels will extend service life.

• Use thread sealant tape on the NPT gauge port as supplied.
• Torque AN/ORB fittings to manufacturer specs; inspect for leaks.
• Verify fuel-line materials are ethanol-compatible when using E85.

Who this is for: Tuners, performance enthusiasts, and shops upgrading or building EFI systems who need a durable, adjustable regulator capable of precise pressure control from 30 to 140 PSI. It’s a good match for custom fuel rails, high-flow pump systems, and vehicles running ethanol blends, provided installation follows best-practice plumbing and safety steps.