D-4 Pure-Flo Filter & 7in. Stainless Hose

The Nitrous Express D-4 Pure-Flo Filter with 7-inch Stainless Hose is a precision nitrous oxide delivery component engineered for high-performance forced-induction systems. This filter assembly removes particulates and moisture from nitrous supply lines, protecting downstream injectors and ensuring consistent jetting accuracy across varying boost conditions. The stainless steel construction resists corrosion in demanding engine bay environments, while the 4 AN (1/4-inch NPT) port sizing matches OEM and aftermarket nitrous manifold specifications.

The 7-inch stainless hose assembly provides routing flexibility around engine bay obstructions without compromising flow dynamics. Pure-Flo filtration technology captures micron-level contamination that can cause injector clogging or erratic spray patterns—a critical concern in competition or street applications where tuning precision determines reliability and repeatability. The aluminum Pure-Flo filter body is lightweight while offering robust pressure ratings suitable for stage 1 through stage 3 nitrous kits. Weighing just 0.7 pounds, the complete assembly adds negligible mass while occupying minimal mounting space.

This component is intended for bracket racing, street performance, and dyno tuning environments where system integrity directly impacts power delivery and engine longevity. Users working with Direct Port Injection (DPI) or direct-shot manifold systems benefit from reduced maintenance intervals and more consistent lap times. The D-4 Pure-Flo Filter is compatible with Nitrous Express complete kit installations and retrofit configurations on vehicles ranging from displacement-limited classes to full-bore combinations. Installation requires basic hand tools and standard AN hose adapters, making it accessible for both shop professionals and experienced enthusiasts.