Nitrous Oxide

By SRT-Tom · Jan 22, 2019 ·
  1. SRT-Tom
    Juice. Squeeze. Laughing gas. Nitrous oxide has many aliases. It can inject a healthy dose of horsepower into an engine, via direct port, carburetor/throttle body plate, air intake tube or, air cleaner injection, to give a race car the winning edge at the track.

    In racing, nitrous oxide (often referred to as just "nitrous") allows an engine to burn more fuel by providing more oxygen than air alone, resulting in a more powerful combustion. The gas is not flammable at a low pressure/temperature, but it delivers more oxygen than atmospheric air by breaking down at elevated temperatures. Therefore, it often is mixed with another fuel that is easier to deflagrate. Nitrous oxide is a strong oxidant, roughly equivalent to hydrogen peroxide, and much stronger than oxygen gas.

    It is stored as a compressed liquid. The evaporation and expansion of liquid nitrous oxide in the intake manifold causes a large drop in intake charge temperature, resulting in a denser charge, further allowing more air/fuel mixture to enter the cylinder. Sometimes nitrous oxide is injected into (or prior to) the intake manifold, whereas other systems directly inject, right before the cylinder (direct port injection) to increase power.

    The technique was first used during World War II by the German Luftwaffe to boost the power output of its aircraft engines. Technological considerations limited its use for emergency power and for extremely high altitudes.

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    One of the major problems of using nitrous oxide in a reciprocating engine is that it can produce excessive power to damage or destroy it if its mechanical structure is not properly reinforced. It is very important with nitrous oxide to maintain proper operating temperatures and fuel levels to prevent "pre-ignition" or "detonation" (sometimes referred to as "knock"). Since nitrous oxide allows a much denser charge into the cylinder, it dramatically increases cylinder pressures. The increased pressure and temperature can cause problems such as melting the piston or valves. It also may crack or warp the piston or head and cause pre-ignition due to uneven heating.

    For nearly thirty years, the application of nitrous oxide on vehicles would be privileged information. Racers dabbled with nitrous oxide injection from time to time with varied results. It wasn't until the late 1970s when two racers perfected its use and founded the company Nitrous Oxide Systems (NOS). During the first several years, NOS spent most of its resources demonstrating that nitrous oxide was an efficient, safe form of performance enhancement. The effort paid off, as NOS quickly became known for producing easy-to-install kits made from the highest quality material available. Hands-on use and tech support were the key to the company's success.

    The advent of drag racing's Pro Mod class in the 1980s provided a boost of popularity to NOS. In fact, both the first 200-mph run and the first 6-second run were aided by NOS. Racers and performance enthusiasts at every level took notice of these remarkable feats. It is conceivable to say that nearly every significant performance milestone with nitrous was done with the NOS brand. Race reports show that the NOS brand still powers more racers than all others.

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    In 2001, the summer blockbuster movie, The Fast and the Furious, displayed a subculture to which NOS belongs. Serious performance enthusiasts knew about NOS, but now the world would know of the brand and its potent power potential. Recent new products such as the Launcher™ and POD (Pressure On Demand) nitrous controllers show why the NOS brand is still #1.

    Dry and wet nitrous kits are available from other suppliers, as well. Among the biggest names are: Nitrous Express (NX), Zex, Edelbrock, Ny-Trex and Venom High Performance.

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    In a naturally aspirated engine, gaining 35-55 horsepower, through “bolt-ons,” can be extremely expensive. Nitrous, however, provides the biggest "bang for the buck." A nitrous kit costs from $500-700, and can instantly strap on up to 150 horsepower. The kits are usually pretty straight forward to install and nitrous refills are about $40-50 per bottle.

    The thing about nitrous that makes it unique compared to other forced induction solutions, is that it produces torque instantly. Whereas a turbocharger produces variable amounts of additional torque based on how much boost it's producing, nitrous instantaneously adds torque with no lag. For this reason, even in high powered turbo cars, you'll often see nitrous added to make up for turbo lag caused by the enormous turbocharger and get the car into boost faster. It doesn't matter if you're at 2,500 rpm or 8,000 rpm, you'll still get gobs of torque with nitrous. Typically, this means that given the same peak power output, a nitrous car will beat an all-motor or turbo/supercharger car, all else being equal and traction dependent.

    The thing about nitrous that makes it unique compared to other forced induction solutions, is that it produces torque instantly. Whereas a turbocharger produces variable amounts of additional torque based on how much boost it's producing, nitrous instantaneously adds torque with no lag. For this reason, even in high powered turbo cars, you'll often see nitrous added to make up for turbo lag caused by the enormous turbocharger and get the car into boost faster. It doesn't matter if you're at 2,500 rpm or 8,000 rpm, you'll still get gobs of torque with nitrous. Typically, this means that given the same peak power output, a nitrous car will beat an all-motor or turbo/supercharger car, all else being equal and traction dependent.

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