Fuelab 51506-3-L-E Series EFI Adjustable Fuel Pressure Regulator Large Seat - 515 6AN/-10AN

The Fuelab 515 Series Adjustable Fuel Pressure Regulator (PN: 51506-3-L-E) is an EFI-spec, large-seat regulator engineered for performance fuel systems that demand precision and reliability. Designed with flexibility in mind, it accommodates both port-style and non-port-style union fittings without interference. The 515 Series supports a wide range of applications — from carbureted setups operating as low as 1 PSID all the way up to fuel-injected systems running up to 125 PSID.

Constructed from billet aluminum with a military-spec anodize finish (MIL-A-8625, Type II), this regulator offers exceptional durability and corrosion resistance. Its fine-thread adjustment mechanism delivers precise pressure tuning, and the versatile mounting bracket with stainless steel hardware makes installation straightforward in a variety of engine bays and fuel system layouts.

Key Features:

• Two inlet ports accepting -6AN or -10AN fittings, plus one -6AN return port located on the bottom
• Compatible with gasoline, diesel, methanol, and ethanol fuels
• Billet aluminum construction with military-spec anodize (MIL-A-8625, Type II)
• Fine-thread pitch adjustment for highly accurate pressure setting
• Includes versatile mounting bracket and stainless steel hardware
• 1/8 NPT gauge port with plug for connecting an external fuel pressure gauge
• 1/8 NPT pressure reference port with barbed fitting for MAP/vacuum referencing
• Large seat design optimized for EFI applications
• Backed by a 2-year limited warranty

The Fuelab 515 Series regulator is an ideal choice for high-performance EFI builds, forced-induction applications, and any fuel system requiring reliable, adjustable pressure control across a broad operating range.