High-Speed Bypass; 65 - 130 PSI with 6AN fitting

The KINSLER High-Speed Bypass fuel valve (Model 3981) is a precision-engineered fuel pressure regulator designed for high-performance fuel systems operating in the 65–130 PSI range. This aluminum bypass valve with 6AN inlet and outlet fittings provides accurate pressure relief, making it essential for fuel-injected performance engines, race vehicles, and specialty automotive applications where consistent fuel pressure stability is critical to engine performance and reliability.

The 65–130 PSI operating range allows the valve to maintain target fuel pressure across varying engine load conditions, preventing over-pressurization that can damage fuel injectors or fuel system components. The 6AN threaded connections (industry-standard AN fittings) ensure compatibility with modern fuel line systems and minimize installation complexity. Gray anodized aluminum construction resists corrosion while maintaining a lightweight profile—critical in applications where fuel system weight and durability matter equally. The high-speed relief mechanism responds quickly to pressure spikes, protecting the fuel system from transient pressure events that occur during cold starts, acceleration, or load changes.

This valve is commonly integrated into fuel delivery systems for carbureted-to-fuel-injection conversions, street performance builds, drag racing fuel systems, and any application requiring precise pressure regulation above stock fuel pump capabilities. Users building custom fuel systems with higher-volume fuel pumps rely on bypass valves to prevent over-pressurization and maintain consistent injector opening characteristics. The universal design accommodates different fuel system layouts, though proper installation within the correct pressure circuit is essential for safe operation.

KINSLER fuel system components are recognized in automotive performance circles for precision manufacturing and pressure regulation accuracy. Bypass valves in this pressure range are standard in fuel-injected performance vehicles, custom fuel systems, and racing applications where fuel pressure stability directly impacts engine tuning stability and reliability under variable operating conditions.