An Introduction to Nitrous Oxide (N2O) Injection

NOS Canister

Presurized NOS Canister

Nitrous Oxide (N2O), or NOS as it is commonly referred to, is a quick and easy performance boost for any motor vehicle, regardless of whether it's a car, a bike, a boat or a plane. In technical terms, Nitrous Oxide is a chemical compound that consists of two Nitrogen atoms and one Oxygen atom. However, Nitrous Oxide does not occur naturally as a chemical compound but has to be manufactured by applying heat and a catalyst to nitrogen and oxygen compounds. Nitrous Oxide was first discovered by the British chemist, Joseph Priestly, in 1772 but it wasn't until 1942 that Nitrous Oxide was first injected into an internal combustion engine to boost the power output from the engine. Nitrous Oxide is not combustible and is in liquid form when under pressure. When it is released into the combustion chamber the pressure is removed and the Nitrous Oxide becomes gaseous, releasing extra Oxygen that allows your engine to burn more fuel during the combustion process. At the same time, the chemical process of changing from a liquid into a gas absorbs lots of the heat from inside the combustion chamber, reducing the chances of detonation and pre-ignition. NOS thus provides an instant but relatively safe performance boost.

The Pro's and Con's of Nitrous Oxide Systems

The major advantage of NOS is that, in terms of cost per horse power (hp), it is relatively cheap when compared to all the other forms of engine modification and the amount of work involved to install a full nitrous system is far less than that of installing high performance cam shafts, turbochargers or superchargers. Furthermore, installing a nitrous system is fairly easy, as we'll soon see, can be applied to any car and can easily be removed and transferred to another car. The only drawback is that you must refill your Nitrous Oxide tank. Nitrous Oxide is stored in a pressurized tank to keep it in a liquid state. Unfortunately, Nitrous Oxide refills are not as freely unavailable as gasoline and must be purchased from an authorized dealer. The relative low cost of installing a NOS system makes it an ideal power boost project for anyone who can read and understand a little simple physics. Furthermore, it can provide any desired power increase from 25 hp all the way to over 500 hp without affecting drivability or fuel consumption when not "on the button". As with anything in life, if you don't do it right, you're going to get problems. There is also more to installing NOS than just bolting a NOS tank to your trunk and connecting a long tube to your engine. The bottle has to be mounted at a 15° angle to ensure that the last of the gas is used and none is wasted. The plumbing is also a bit intricate and can be a little tricky for a first time NOS installer.

None the less, in this section, we will explain the physics of nitrous oxide injection and show you how to install a NOS kit and how to test and tune a NOS system.

There are three different types of nitrous oxide systems that you can implement:

  • The Dry System, which is the NOS system in which no fuel is sent to the intake charge outside the vehicle's normal means.
  • The Wet System, which is the NOS system in which fuel and nitrous oxide are supplied through a fogger and then sprayed through the throttle body.
  • The Direct Port System, which is a Wet System in which each engine cylinder has its own fogger.

We cover all of these over the next few pages, and we have a page of frequently asked questions at the end. Now let us start with some NOS basics ...

WARNING: NOS causes an extreme increase in fuel combustion; therefore, any problem in your engine can turn out to be 10 times worse with nitrous installed!