Hit the button and feel the blast of power. If you've ever done it, then you know what we're talking about, and if you haven't,then it's an experience you don't want to miss. With nitrous oxide, horsepower increases ranging anywhere from a 50hp shot to 500-plus is easily achieved by the flick of a switch. Most kits come complete, ready to bolt on, and can be installed in an afternoon with common hand tools. How nitrous works, what's available, what's new on the scene, and what modifications, if any, need to be done prior to installation are the issues we're going to address.
When installed properly, a nitrous kit can provide an easy and economical way to raise the power level of any engine. As with any engine modification, you'll want to gain a thorough understanding and match the parts to your application in order to gain the most performance.
Nitrous oxide can be translated into its chemical composition, two parts nitrogen and one part oxygen. As combustion temperatures inside your engine reach almost 600 degrees F during operation, the supplied amount of nonflammable N2O breaks down and releases oxygen to provide an environment for additional fuel to be burned within the combustion chamber, while the inert nitrogen manages the burn rate, so it's more like a fuse than a stick of dynomite. Once the high concentration of oxygen and extra fuel is ignited during the power stroke, there is a dramatic rise in cylinder pressure, resulting in substantial power gains.
Types of Systems
Nitrous oxide is available in two basic varieties: wet and dry. A wet system delivers both nitrous and fuel, which can be injected in a number of ways, including a carburetor-plate system, which rests below the carburetor, or through a throttle-body plate or a nozzle in most fuel injected engines. For most street/strip applications, a plate system offers easy installation and removal. Changing jets with plate kits is easy too, and power increases up to 350 are very obtainable.
For more aggressive systems, or those more commonly used in dragstrip applications, there is a direct-port style, also known as a fogger system, that supplies both nitrous and fuel directly into each intake runner. This type of system mixes and manages both the fuel and the nitrous into each cylinder, allowing for maximum tunability. It is the most powerful type. Another benefit of a fogger or direct-port system is that very liberal amounts of nitrous and fuel can be evenly fed into each cylinder.
A dry nitrous system is used in a dry-style fuel-injection intake manifold where air enters at the inlet and fuel is supplied just above each intake port. In this system the nitrous is sprayed into the air inlet, where it changes into a gas (inside the manifold's plenum) and the extra fuel required to produce the added power is supplied through the standard fuel injectors (located just above each intake port). The additional fuel is delivered in this system by increasing fuel pressure through the injectors.
Nitrous, Engine Components & IgnitionsChoosing, installing, and tuning the nitrous system correctly for your application are key to maintaining engine reliability and longevity. Nitrous oxide should only be introduced into the engine at full-throttle and above 2,500 rpm. If it's applied sooner, severe engine damage can occur due to high cylinder pressure at lower engine speeds, placing a tremendous load on the internal engine components. Performance street cars with nitrous should typically limit compression ratios to 9.5- to 10:1, and run 91- to 93-octane pump fuel. Camshaft choice is important too. Typically, a cam with less overlap and added exhaust duration is a good choice. Camshaft catalogs list specific grinds to use with nitrous that can match your vehicle's weight, gearing, and performance target.