AEM High Capacity Adjustable Fuel Pressure Regulator (40-130 PSI, -6AN, E85) – Universal for Turbo Engines and Competition

The AEM 25-305BK is a high-performance fuel pressure regulator built for systems that demand high flow and stability. It features an oversized return port and a long-travel spring that eliminate pressure fluctuations even with 400+ LPH fuel pumps. Perfect for turbo engines, race builds, and any project that needs consistent pressure under extreme conditions.

Features

• 40 to 130 PSI range (2.76 – 8.96 bar) — Long spring allows precise adjustment without losing stability.
• Large return port — Handles high-flow pumps without creep or unwanted pressure spikes.
• 1:1 rising rate — Automatically increases fuel pressure in parallel with turbo or supercharger boost.
• Compatible with E85, methanol, and race fuels — Internal materials resist corrosion from aggressive fuels.
• 6061-T6 billet aluminum body, CNC machined — Black anodized, robust, and professionally finished.

Technical specifications

• Reference: AEM 25-305BK
• Pressure range: 40 – 130 PSI (2.76 – 8.96 bar)
• Inlet ports: 2 × -6AN ORB (9/16"-18)
• Return port: 1 × -6AN ORB (9/16"-18)
• Gauge port: 1/8" NPT
• Vacuum/boost connection: 3/16" (5 mm)
• Factory setting: 40 PSI
• Material: 6061-T6 billet aluminum
• Finish: Black anodized

Compatibility

Universal. Fits EFI (electronic fuel injection) and high-pressure carburetor systems. Optimized for turbocharged, supercharged, and high-output naturally aspirated engines. Compatible with gasoline, E85, ethanol, methanol, and race fuels.

Why the High Capacity model?

Unlike standard regulators (such as the AEM 25-302BK), the 25-305BK eliminates the creep phenomenon that occurs with high-flow pumps (+400 LPH). Its one-piece return port ensures excess fuel returns to the tank without restriction, keeping fuel rail pressure stable at all times.

FAQ

• Is it compatible with E85? Yes, all internal components resist corrosion from alcohol-based fuels.
• Does it include a gauge? No, but it has a standard 1/8" NPT port for installing the gauge of your choice.
• Will it work for street use? Yes, it works perfectly for both street and track.

Package contents

• 1 × AEM 25-305BK fuel pressure regulator
• 1 × Universal mounting bracket
• 4 × Mounting bolts

Shipping & warranty

In stock. Fast shipping and guaranteed compatibility with systems using -6AN fittings.