Nitrous Oxide

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Nitrous Oxide

What is Nitrous Oxide?

Typical Nitrous Oxide Kit - Image courtesy of enginebasics.com

Nitrous Oxide is a colorless, non-flammable gas (at room temperature) that is used in automotive racing to dramatically increase horsepower. Nitrous Oxide does not increase horsepower by burning, it is an Oxidizer that allow an engine to burn more fuel by significantly increasing the oxygen content of the mixture.

An engine makes power based on the amount of fuel it burns. You can easily pump more fuel into the engine, but what limits the amount of fuel an engine can burn is the amount of oxygen required to burn it. Therefore, what actually limits an engine's ability to make power, is the amount of air (oxygen) it can breathe. So racers do all sorts of things to let an engine breathe more air, rev it higher, bigger displacement, freer flowing parts, superchargers, etc.

Nitrous oxide attacks this problem from a different angle, don't change the amount of air the engine can breathe, but the amount of oxygen it can breathe. Air contains only about 20% oxygen, where nitrous oxide contains about 36% oxygen. If you add nitrous oxide, you increase the total mixture's oxygen level significantly over 20% up to 25-30%, which allows for a 25-50% increase in oxygen level (30% compared to 20% is a 10 percentage point increase over 20%, or 10/20 = 50%).

Nitrous oxide has additional benefits for performance. It is typically injected into the intake manifold as a liquid, which takes up much less volume than as a gaseous nitrous oxide. This means very little air is displaced. Or, if any evaporation of the nitrous oxide occurs, it significantly cools the intake charge, again allowing for a cool, dense charge. This cooling helps cool engine parts and reduces Detonation.

How it works

Nitrous Oxide components usually come in kits that have most of the parts you need to install the kits on your vehicle. They consist of a bottle that holds the Nitrous Oxide (usually installed in the trunk or rear of the vehicle), tubing to run the gas from the rear of the vehicle to the engine, a controller that is located within the reach of the driver, and nozzles or adapter plates to inject the Nitrous Oxide into the engine.

Types of Vehicles

You can get Nitrous Oxide kits for just about any type of vehicle. The majority of Nitrous systems are installed on cars or trucks. But some companies also make systems for Motorcycles, ATV's and even Snowmobiles.

Types of Systems

There are 2 main types of Nitrous systems, Wet and Dry systems. The designation refers to the intake manifold. If the fuel system goes through the intake manifold, the manifold gets wet and therefore it is considered a wet system. If the fuel injectors inject the extra fuel required then the intake manifold stays dry and therefore it is considered a dry system.

Wet Systems

There are 2 types of wet systems, Single Point and Direct Port. Wet systems typically allow greater horse power increases over Dry Systems.

Wet Single Point Systems

A Wet Single Point Nitrous Oxide Kit - Notice the plate that goes inbetween the carb and intake manifold. Image courtesy of Nitrous Oxide Systems

Wet single point systems inject Nitrous Oxide into the manifold at a single point so it mixes with the fuel and air mixture.

Wet Direct Port Systems

A Wet Direct Port Nitrous Oxide System - Notice the individual nozels that are directly inserted into the intake manifold. Image courtesy of Nitrous Express

Direct Port systems have individual Nitrous Oxide injectors for each port. These systems are more complex and therefore more extpensive than Single Point systems.

Dry Systems

Dry Systems are similar to Wet systems in the way they deliver Nitrous. The difference is in the way the fuel is delivered to the engine. The fuel does not travel through the manifold to the Cylinder Head. The fuel is delivered after the manifold and therefore the manifold is kept dry of fuel.