The power potential of nitrous oxide was thrust into the spotlight during World War II when German Messerschmitt fighters would suddenly accelerate away from pursuing Allied aircraft, sometimes leaving a puff of smoke in their wake. The planes had a hot button that would supply a short burst of nitrous-generated speed. It would take some time for this technology to trickle into the automotive scene. The trial-and-error evolution of nitrous oxide in the '60s and '70s gave many the perception that nitrous was a volatile means of producing power. In the 1990s computer controls became an integral part of nitrous systems and this volatile aura began to fade. Today, nitrous oxide is a safe power adder as long as the system is jetted to realistic power levels, there is enough fuel supply on-hand and the system is installed properly. So don't expect to pump 300-hp worth of nitrous into a stock 92-hp Honda DX engine, be sure the fuel system is upgraded to match the expected power level and closely follow the supplied instructions or have an experienced shop do the wrenching.

The biggest value of nitrous is its versatility. It doesn't care what car or engine you have; hook it up right and it will make power. While there are application-specific kits offered, universal nitrous is a big answer to those who own "they don't make anything for my car" cars.

Nitrous On A Molecular Level
A power adder allows an engine to burn more fuel and burning more fuel is the only way to make more power. But to make power in an internal combustion engine there must be a proper ratio of fuel and air. It is the air portion of the equation where nitrous makes its impact felt. Nitrous oxide is a molecule with two nitrogen atoms and one oxygen atom. In the nitrous bottle and under pressure the nitrous is in liquid form. When it is released through the nozzle it turns to gas. The act of combustion breaks the chemical bond of the molecule, releasing the oxygen atom. By weight, air is 23-percent oxygen while nitrous is 36-percent oxygen. So there is more oxygen present in the nitrous-enhanced combustion chamber ready to make power. When the proper amount of fuel is introduced and sparked that's what happens-more power.

Dry Manifold,Wet-Manifold, Direct PortThere are two basic types of nitrous systems-dry manifold and wet manifold. A dry system uses a nozzle to inject only nitrous into the intake tract. Fuel enrichment is handled via the fuel injectors by increasing fuel pressure or injector pulsewidth when the system is activated. A wet system injects fuel and nitrous through the same nozzle. In conventional set-ups the amount of fuel and nitrous injected into the engine is determined by the orifice size of the jets installed in the nozzle. The typical system is activated by a throttle-mounted Hobbs switch that fires the nitrous solenoid and releases the nitrous when the engine sees wide-open throttle.

A possible drawback with a single-nozzle system is it relies on the design of the intake manifold to distribute the nitrous or nitrous/gasoline mixture to the cylinders. By virtue of their design or casting shifts some intake manifolds do not distribute air evenly to all the cylinders and as the power levels of the nitrous system increase the small differences in flow become more critical. At best, there is less precise distribution and a tuning challenge-at worst, the chances of creating a lean condition are increased.