Fuelab 51506-6-L-L Series Adjustable Fuel Pressure Regulator CARB Large Seat - 515 6AN

The Fuelab 515 Series Adjustable Fuel Pressure Regulator (PN 51506-6-L-L) is a high-performance, billet aluminum fuel pressure regulator engineered for both carbureted and fuel-injected applications. Built with flexibility in mind, it accepts both port-style and non-port-style union fittings without interference, making it a versatile choice for a wide range of fuel system builds. This CARB-compliant, large-seat configuration features a -6AN return port located on the bottom of the regulator.

The 515 Series supports an impressive pressure range, from as low as 1 PSID for carbureted setups to as high as 125 PSID for fuel-injected applications. Its fine-thread pitch adjustment mechanism allows for precise pressure tuning, while its durable military-grade anodized finish ensures long-lasting corrosion resistance.

Key Features:

• Two -6AN or -10AN inlet ports and one -6AN return port (bottom-mounted)
• Compatible with gasoline, diesel, methanol, and ethanol fuels
• Constructed from billet aluminum with anodizing per military spec MIL-A-8625, Type II
• Fine thread pitch for precise, repeatable pressure adjustment
• Includes a versatile mounting bracket and stainless steel hardware
• 1/8 NPT gauge port with plug for connection of an external fuel pressure gauge
• 1/8 NPT pressure reference port with barbed fitting for MAP/vacuum referencing
• CARB compliant — legal for use in California and all 50 states
• Backed by a 2-year limited warranty

The Fuelab 515 Series is a premium solution for enthusiasts and builders seeking a reliable, adjustable fuel pressure regulator with broad fuel compatibility and race-proven construction. Its robust feature set and military-grade materials make it suitable for street, strip, and track applications alike.