SKU: HLY12-848
UPC: 090127670521
MPN: 12-848
The Holley 4500 Billet Fuel Pressure Regulator with EFI Bypass (Model 12-848) is a precision-engineered fuel system component designed for high-performance and custom EFI engine builds. This in-line regulator delivers consistent fuel pressure across a wide operating range while maintaining the flexibility to support diverse fuel types and engine configurations.
Featuring a billet aluminum construction with black and clear anodized finish, this regulator operates across 15 to 65 psi, accommodating gasoline, diesel, and E85 fuel systems. The 10 AN female O-ring inlet and outlet connections ensure secure, leak-free integration with premium fuel lines, while the 8 AN O-ring return port and 1/8 inch NPT port provide flexible plumbing options. The EFI bypass function allows for proper system regulation without excess return flow, critical for fuel-injected engines that demand stable pressure at varying load conditions. This design prevents fuel system pulsing and vapor lock while optimizing injector spray patterns across the RPM range.
This regulator suits builders developing carbureted-to-EFI conversions, engine swaps, and forced-induction setups where OEM fuel systems fall short of flow or pressure requirements. Its dual-fuel compatibility and adjustable pressure range address the needs of street machines, race engines, and alternative-fuel platforms. The compact footprint (5.3 x 2.9 x 5.4 inches, 1.35 lbs) fits tight engine bays without sacrificing durability or precision, making it a reliable choice for demanding fuel system architectures.
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