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Nitrous oxide exists in the form of liquid in tanks but it changes to a gaseous state under atmospheric conditions. When the nitrous oxide is injected as a liquid into an inlet manifold, the nitrous oxide is vaporized where the expansion reduces the air/fuel charge temperature, thereby increasing the volumetric efficiency of the cylinder.
When the nitrous oxide is heated to about 500 degrees F, it breaks into oxygen and nitrogen. Therefore the injection of nitrous oxide carries more oxygen molecules during combustion that allows adding more fuel to produce more power.
When the Chevy 302 engine is boosted with help of nitrous oxide, the dyno results are plotted below. The increment in HP is roughly the same regardless of RPM. However, the torque is reinforced more effectively at low RPM regions.
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| Measurement data: The flow rate of nitrous oxide is constant regardless of rpm, respectively |
Keeping the average cylinder pressure below 300psi should be able to avoid detonation. If the cylinder pressure is high, the power-stroke may be stronger that may create more torque at low rpm.
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| Measurement data |
The wet nitrous oxide system allows the fuel mixing with a nitrous stream at nozzle. This suits the high power condition. However, it may cause backfire in the intake manifold if the installation is poor. On the other hand, a dry nitrous oxide system is easy to install.