Nitrous Oxide Purge Kit
Nitrous Express 15601 Nitrous Purge Valve Kit with 6AN Manifold and Push Button
What Is a Nitrous Oxide Purge Kit?
A nitrous oxide purge kit is a purpose-built assembly that connects to your existing N2O feed line and uses a dedicated solenoid valve to vent trapped air and gaseous nitrous from the system before activation. The core function is simple but critical: nitrous oxide purge kits ensure that only dense, liquid-phase nitrous oxide reaches the injector solenoid at the moment you hit the button — not a mixture of gas and air that can delay or dilute the power hit.
Why Purging Your Nitrous System Matters
When nitrous sits in the feed line between runs, especially in braided stainless hose, it can transition from liquid to gaseous phase. Fitting a purge kit enables the user to vent off the gaseous nitrous from the supply line prior to activation, which ensures that liquid nitrous reaches the engine as quickly as possible and at maximum density. On wet nitrous systems in particular, air trapped in the nitrous feed line can cause the fuel side to arrive at the nozzle first, creating a rich stumble or bog right off the line — the exact opposite of what you need when staging at the strip. A quick, controlled purge before the run clears the line and puts dense liquid nitrous right at the solenoid, ready for instant delivery.
Beyond raw performance, a purge kit can also be used to relieve excessive bottle pressure on hot days, helping dial in consistent nitrous delivery run after run. The best time to purge is just before staging: a couple of short bursts until you see the characteristic white cloud is typically all it takes.
What's in a Purge Kit?
Most kits include everything needed for a complete installation:
- A dedicated purge solenoid (often a high-flow unit rated in AN line sizes such as -4 AN or -6 AN)
- An inline manifold or tee fitting to tap into the existing nitrous feed line
- A push-button activation switch
- A vent tube to direct purged nitrous safely away from the engine bay
- All necessary fittings, hardware, and wiring
Some kits add illuminated LED assemblies that light up the purge cloud for a dramatic visual effect at car shows and nighttime events — functionality and showmanship rolled into one.
Top Brands in Nitrous Oxide Purge Kits
NOS (Nitrous Oxide Systems) is arguably the most recognized name in the nitrous world. Born from the ingenuity of racers who pioneered nitrous oxide injection for automotive use, NOS established a reputation for producing high-quality, easy-to-install kits. Their Ntimidator line of purge kits features bright blue LED illumination, single or dual purge outlets, and compatibility with any -4 AN feed-line system — blending race-proven function with unmistakable street presence.
Nitrous Express (NX) brings deep nitrous expertise to their purge valve kits, offering options designed to work with both carbureted and EFI plate systems. The NX purge system is designed to purge the air from your nitrous lines to allow immediate activation, and also serves double duty by helping manage bottle pressure for consistent performance every single pass.
Choosing the Right Purge Kit
When shopping, consider your existing feed-line size (-4 AN vs. -6 AN), whether your nitrous solenoid already has a dedicated purge port, and whether you want a purely functional unit or one with show-worthy LED lighting. Ensure the purge solenoid is mounted as close to the main nitrous solenoid as possible to minimize residual air volume in the line. With the right kit installed, your nitrous system will be primed and ready to deliver every bit of its rated horsepower the instant you activate it.