Nitrous Oxide System

Nitrous Oxide

Nitrous oxide carries more oxygen to the engine, allowing for faster burning of the fuel and generating more power. At high temperatures, such as those found inside a firing cylinder, nitrous oxide breaks down into nitrogen and oxygen gas. This raises the partial pressure of oxygen in the gas mix above the level found in normal atmospheric air, and lets the fuel burn more efficiently.

Nitrous oxide is also incorrectly called 'NOS' among racers after one of the first companies to provide nitrous systems, Nitrous Oxide Systems. This is normally sounded out by letter ("en-oh-es") by pro mod drivers, although some pronounce it as a word (like "naws"). Today, there are several competing companies in the field, including ZEX, NOS, Nitrous Direct, Nitrous Express, and Nitrous Works.

Nitrous systems can increase power by 45% or more, depending on configuration, and are usually built in one or two stages. All Pro Mod cars and some Pro Steet cars use three stages, for additional power.

Fans can easily identify nitrous-equipped cars at the track by the fact that most will "purge" the delivery system prior to reaching the starting line. A separate electrically-operated valve is used to release air and gaseous nitrous oxide trapped in the delivery system. This brings liquid nitrous oxide all the way up through the plumbing from the storage tank to the solenoid valve or valves that will release it into the engine's intake tract. When the purge system is activated, one or more plumes of nitrous oxide will be visible for a moment as the liquid flashes to vapor as it is released. The purpose of a nitrous purge is to ensure that the correct amount of nitrous oxide is delivered the moment the system is activated - Air or gaseous nitrous oxide in the line will cause the car to "bog" for an instant until liquid nitrous oxide reaches the intake.