Juice. Squeeze. "Nawz." Whatever you want to call it, there's no denying that nitrous oxide is synonymous with power. We work hard to get our engines to pull more air. Manifolds, ported heads, big cams, tuned headers, fat blocks with mega cubes, sky-high rpm-the whole freakin' show is about getting more air into the engine to support more fuel burning, to make more horsepower. Air takes up quite a bit of volume at atmospheric pressure, and getting more of it involved in the combustion process takes more cubes, more rpm, or greater efficiency moving in and out with the cubes you've got. Distill it down and that's all there is. There are limits to rpm and how efficiently the engine sucks in air, uses it up, and spits it out. This is the volumetric efficiency of the engine, and 100 percent is doing good.

Scienced-out race engines with tuned intakes, exhausts, and cams can exceed 100 percent in a narrow range of rpm, but ultimately there is only so far it can go with just atmospheric pressure and the engine's displacement providing the pull. This translates to limits on power production-not in horsepower, which can keep going up with rpm-but with torque output per cube. A really good street engine can touch 1.25 lb-ft per cubic inch, and an exceptional one may get in the 1.3 range. Race engines don't see much more.

Want more? It will take more air. With supercharging, either by a crank-driven blower or a turbo, we can get more air in the engine. This ups the torque-per-cube output, which equals more horsepower. Nitrous does the same thing, but instead of adding more air, oxygen-rich nitrous oxide is injected to support the combustion process. Nitrous, truly, is liquid horsepower with the ability to boost torque to the limits of an engine's ability.

Nitrous contains 36 percent oxygen by weight, with nitrogen as the other component of the chemical compound. Under the heat of combustion at 572 degrees fahrenheit, the compound separates, releasing oxygen that supports burning more fuel, thus making extra power. The nitrogen component stabilizes the process. Modern nitrous systems consist of two circuits: one injects extra fuel, which actually makes the BTUs that produce the power, and the other is the all-important nitrous oxide, there to support the burning of that extra fuel. With solenoids controlling the injection of the added fuel and nitrous, more power is literally the flip of a switch away.

Unlike a normally aspirated engine, the output per cube with nitrous isn't limited by the efficiency and displacement of the engine. Big-block torque numbers (or more) across the entire rpm range are no problem with squeeze and, by definition, that added torque is added horsepower.

Unlike a conventional supercharger that creates heat when building boost, nitrous creates a cooler temperature. The nitrous is stored under high pressure as a liquefied gas. Once released into the intake manifold or port, the liquid nitrous changes to a gas form. As you physicists know, the rules of the latent heat of vaporization dictate that heat energy is absorbed from the surroundings in the process. For the rest of us it just means that injecting nitrous cools the intake charge, making a denser, more powerful mixture.