When you browse through the catalog at your local speed shop, you'll see a variety of different performance parts which are designed to help improve the amount of air that flows into an engine: cold air intakes, ram air induction, turbochargers and superchargers, etc. However, the one modification that you can make to your import's air flow that also provides some of the best bang for your buck is nitrous oxide injection.

Nitrous oxide has acquired somewhat of a mythical status in the compact car performance scene thanks to its idolization in the media and in the movies. We are all familiar with the scene where our hero pushes the little red button on his steering wheel and wins the race. But how does this gas really work? Essentially, when nitrous oxide or N20 is introduced into a vehicles intake, the heat of the engine causes it to it break down into its component gases nitrogen and oxygen. Since nitrous oxide is an extremely dense gas, there is a significantly larger amount of oxygen locked up inside of it in comparison to that which is found in the atmosphere. This drastically increases the amount of oxygen available for combustion, and as a result, the amount of horsepower that can be produced also goes up. In small displacement, 4-cylinder motor, nitrous oxide can be a great equalizer when it comes to performance.

There are a few different ways you can inject nitrous oxide into your engine. The cheapest and least complicated method is to use what is called a dry kit. A dry kit sprays the gas into your cars intake and then convinces the engine to add more fuel to the mix. If you go this route, it is extremely important that your cylinders be provided with enough fuel to deal with the extra oxygen, or you might be looking at an expensive paperweight when you pop your hood at the end of a run.

This is why many people opt for a wet kit, which uses an extra fuel injector to spray a mixture of nitrous oxide and fuel into the intake.

This method helps to ensure that the correct mixture will be maintained in the engine, but it can also lead to fuel puddling in the intake - where it could ignite and cause an explosion. Sound scary? It is, and thats why you want to make sure that your nitrous kit is installed by a professional.

The most expensive form of nitrous oxide injection, and also the safest and best method when it comes to producing maximum power, is called direct port injection. In this version, fuel and N20 are introduced into each individual cylinder, providing a much more direct mixture control.

Nitrous oxide is not an always-on type of modification as it should only be used when the vehicle is under wide open throttle and you might not like the fact that your extra power is limited by how much gas you've got left in the bottle. That being said, with kits that offer 200 additional horsepower or more, it is hard to deny the appeal of this piece of bolt-on performance equipment.