By: Mark K. (FushigiRES)

Over the years, as I speak with individuals about performance upgrades for their cars, I seem to get the same few question with each conversation. “How do you feel about nitrous? What are the pros and cons? Is it safe? How does it create power, and which system is best? They are all good questions, ones that form the basic fundamentals of understanding when choosing and tuning with a nitrous setup.

Before I explain nitrous systems further, I will first explain the properties of nitrous. Nitrous, or nitrous oxide, is composed of two parts nitrogen and one part oxygen. When the nitrous is injected into the engine and is introduced to the extreme temperatures of the combustion process, it breaks down into its two elements (break down occurs at 572 desgres F). With the additional oxygen readily available, the engine is able to burn more fuel. The nitrogen in the combustion chamber helps to keep the combustion process under control and stabilize the cylinder pressures. In addition to providing additional oxygen, injected nitrous reduces the intake charge by 50 to 80 degrees from base.

There are two types of nitrous kits available on the market. They are: a “dry” nitrous system and a “wet” nitrous system. The dry setup injects the nitrous into the intake tract and relies on the car’s ECU to detect a “lean condition” and add additional amounts of fuel proportionate to the air/fuel ratio detected by the computer. The ECU can also adjust timing for maximum engine performance. To get the most out of the dry kits, it is imperative that the nozzle be placed further from the throttle body. I recommend a minimum distance of 2’-6” between the nozzle and the throttle body. By keeping the nozzle further away, it allows the injected nitrous to cool the incoming air more efficiently and in larger volumes by having additional time to do so. Dry kits tend to max out at a 75 hp shot before they become dangerous. Any attempts to push your shots higher with a dry system, without support parts, will in all likely hood, end with catastrophic engine failure.

Wet kits inject additional fuel with the nitrous via a “tee” in the fuel line before the car’s fuel pressure regulator. When installing a wet kit, it is better to have the injection nozzle closer to the throttle body in order to control the possibilities of backfiring. Backfiring is a concern for wet systems because when you engage the system you are filling the intake manifold with an explosive mix of fuel, nitrous, and a cool air charge. Keeping the nozzle close also allows for even fuel distribution within the IM and decreases the possibility of fuel pooling up in the IM, which in turn leads to backfiring. The wet kits allow for added tuning by enabling the tuner to try different combinations of jets to obtain the correct fuel to nitrous settings.

Stay tuned for part two where I will explain the necessary support components, and how to tune dry and wet systems….