Fuelab 52503-1-S-G 525 Series EFI In-Line Adjustable Fuel Pressure Regulator 90-125 PSI Black

The Fuelab 52503-1-S-G is a high-performance, adjustable EFI fuel pressure regulator from the proven 525 Series lineup. Engineered for fuel-injected applications requiring elevated pressures, this in-line regulator features a 90–125 PSID pressure range, a single -6AN inlet, and a -6AN return port mounted in-line with the inlet — not on the bottom — making it significantly easier to install in tight engine bays with limited clearance.

Machined from billet aluminum with a military-spec MIL-A-8625 Type II anodized finish in black, this regulator is built for durability and long-term corrosion resistance. The fine-thread adjustment screw allows for precise fuel pressure tuning, while the included versatile mounting bracket and stainless steel hardware simplify installation. A standard seat configuration is used for this pressure range.

Key Features:

• Pressure Range: 90–125 PSID — ideal for high-pressure EFI applications
• -6AN inlet and -6AN return port oriented in-line for tight-clearance installations
• Compatible with gasoline, diesel, methanol, and ethanol fuels
• Billet aluminum construction with military-spec MIL-A-8625 Type II anodize in black
• Fine-thread pitch adjustment screw for precise pressure control
• Accepts both port-style and non-port-style union fittings without interference
• 1/8 NPT gauge port with plug for optional external fuel pressure gauge
• 1/8 NPT pressure reference port with barbed fitting included
• Includes versatile mounting bracket and stainless steel hardware
• Backed by a 2-year limited warranty

The 525 Series is designed for single fuel rail configurations where the return line exits from the same end as the inlet, eliminating the need to route return lines around the regulator body. This regulator is intended for racing, off-road, or marine use and is not legal for sale or use on emission-controlled motor vehicles.