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What is NOS or Nitrous Oxide?

The term NOS is well known in the car world. Not only enthusiasts, the term NOS is already quite familiar to the ears of non-enthusiasts.

NOS or Nitrous Oxide Systems is one method of increasing engine power by injecting nitrous oxide into the combustion chamber . The name NOS is widely known by the public through films such as Fast and Furious and also of course through video games such as Need For Speed. Thanks to both, even small children know this NOS. A kind of magic or stance that can make a car instantly become speeding like a rocket, haha .

Uniquely, this NOS is actually a brand name and not a term or item name. Just like Aqua, Odol, Tipp-Ex, Pylox, and Softex hehe. Usually the brand attached to the name of the term or item is a pioneer brand that develops certain ideas or technologies. Besides NOS, there are still many other nitrous brands / products such as Nitrous Express  (NX) and ZEX .

NOS is a subsidiary or division of an American automotive company called Holley . The company was founded in 1896 which initially produced three-wheeled vehicles. Now this company has grown and produced a variety of automotive components for racing or performance purposes. One of them was NOS.

In addition to the term “NOS”, this technology is often called ” Nitrous Oxide ” or sometimes abbreviated as ” Nitrous “.

In this review we will discuss this NOS in full. Starting from the understanding, how to work, components, advantages and disadvantages, types, and others.

Let’s just start. Are you ready for the coffee?

What is NOS?

NOS or nitrous oxide or we briefly become nitrous, is a compound consisting of two molecular elements Nitrogen and one element Oxygen (N 2 O). At room temperature, this compound is a gas . However, when under pressure, nitrous liquid will become easy to store. Put it in a bottle like a genie, hehe .

So far, sometimes we hear that this nitrous compound is flammable, and can even explode. Because of these properties, nitrous can help combustion in the engine. Contrary to myth, this compound is  actually non-flammable .

Then how can nitrous help combustion in the engine?

When nitrous is released from high pressure bottles, this compound will change form from liquid to gas. Remember the gas lighter? Liquid but if it breaks into gas. Well that kind. This nitrous gas is channeled into the engine’s air intake system which will then enter the combustion chamber.

At temperatures around 300 ° C, the molecular elements of nitrous oxide compounds will separate into nitrogen molecules and oxygen molecules . Well, the heat from compression in the combustion chamber will break nitrous gas and of course provide additional oxygen supply to the combustion chamber.

Adding oxygen means we can increase the amount of fuel that can be burned. This will increase the heat and explosion power in the engine room which will increase the pressure on the piston. The result, increased engine power.

The amount of power increase depends on the amount of nitrous and additional fuel supplied. Generally around 50-150 hp. The increase in power above is possible, as long as the internal engine is able to withstand the pressure / workload. If not, it’s destroyed.

This nitrous enters the forced induction system , such as a turbocharger  or supercharger that we have also reviewed. Although some other circles, there are also those who argue otherwise. Nitrous does not force (compress) air into the combustion chamber, so it cannot be called forced induction.

Nitrous System Components

A nitrous system consists of several components which of course have their respective functions. The following components.

  1. Nitrous Bottle / Tube. High pressure bottles that store nitrous in liquid form.
  2. Nitrous Hose (Nitrous Feed Line). This hose serves to distribute nitrous from the bottle to the nitro plate.
  3. Nitrous Plate. This plate is paired between the throttle body and the intake manifold . This plate is where the nitrous (and fuel) is injected. Nitrous Plate is one method of injecting nitrous, the other type of method we will discuss later.
  4. Solenoids. This component is generally located on a nitrous plate. Its function is a switch on / off for nitrous (and fuel) to be injected.
  5. Fuel adapter (Fuel Rail Adapter) that functions to connect the fuel hose with the fuel rail.
  6. Brass Jets. This eye spray / nozzle , looks like the one in a carburetor. The size varies, depending on the amount of nitrous and fuel that we want to inject.
  7. Electronic components such as relays and sensors. This is used in automatic mode, to connect the solenoids with the throttle sensor (throttle position sensor). As a result, nitrous will automatically activate when the engine is running at a certain RPM speed.
  8. Valve Purge. This component is optional. Its function is to release (remove) the remaining nitrous that is in the nitrous hose after nitrous is used. This is done to ensure the next supply of nitrous can directly enter the nitrous plate. Nitrous gas from the purge process will spray out of the car and is sometimes used for attraction, aka attracting people’s attention.

Nitrous Mechanism / How it Works

At the beginning we had a chance to review a little picture of how nitrous works on the engine. Now we will discuss in more detail. Here is the mechanism or way of working of a nitrous system.

  1. The most common way to activate a nitrous system is through an automatic system that works through a throttle position sensor (TPS sensor). So nitrous will be active when the car reaches a certain rpm range.
  2. The driver will turn the switch on for the nitrous system to be active and standby waiting for the engine to reach the specified rpm. Usually this switch is turned on the teeth 2-3 and above.
  3. After the nitrous system is on and the car has reached the specified rpm range, the nitrous sensor will get a signal from the TPS sensor. Then the nitrous sensor will order the nitrous solenoid and the fuel solenoid to switch on. This will open up the flow of nitrous and fuel supplies to the engine.
  4. As soon as nitrous comes out of the high pressure bottle. His form then turned into a gas because nitrous came out into the normal atmosphere. When it turns into gas, the temperature changes to -88.5 ° C. If the lighter breaks, the gas feels cold, right? Well that kind. This also helps increase engine power because the cold temperatures allow more air to enter the engine cylinder . Which means we can burn more fuel.
  5. When the piston is compressed, the pressure will cause the engine temperature to rise and separate the elements of nitrous (N 2 O) to Nitrogen and Oxygen.
  6. The additional oxygen supply combined with additional fuel will increase the explosion pressure and temperature in the fuel chamber even greater . This is what then increases power from the engine.

The following is a video explanation of the mechanism of action of Nitrous (type of plate system).

Nitrous System Type / Type

There are two main categories for types or types of nitrous systems. This is determined by the method of injecting nitrous and fuel into the engine combustion chamber. The two main types are the dry system and the wet system. The wet system is subdivided into several sub categories such as single wet, multi / direct port, and plate systems.

The following is a summary of the types.

  1. Dry system (dry) is a type of nitrous system that only injects nitrous into the engine without injecting additional fuel . It is called dry because the intake manifold is dry from liquid fuel, so there is only air and nitrous gas. Nitrous injection is carried out in place after the mass airflow sensor. This will give a signal to the ECU that there is additional cold air so the ECU then ordered to increase fuel supply.
  2. Single wet is injecting nitrous mixed with additional fuel at the intake manifold. This makes the intake manifod wet with fuel.
  3. Multi or direct ports are the same as single wet, except that the injection is done at each intake port on the engine.
  4. The plate system we discussed earlier. This wet system injects nitrous and fuel into the plates which are paired between the throttle body and the intake manifold .

Nitrous Strength and Deficiency


  1. Increase labor with cost and effective results.
  2. Can be installed quickly and easily.
  3. Can be deactivated and removed easily.
  4. In drag cars with large power, nitrous can be used as an alternative to controlling car traction.


  1. Excessive use can damage the engine quickly.
  2. Nitrous energy is temporary.
  3. The pressure and temperature of the nitrous bottle must be checked periodically to ensure the bottle can distribute nitrous smoothly.

Myths, Mistakes, and Other Things About Nitrous

  1. Nitrous is flammable so it can explode. We discussed earlier, nitrous oxide (N 2 O) is a non-flammable compound .
  2. In competitions or races, using nitrous is often referred to as underhanded or cheating. Actually the nitrous system is the same as other forced induction systems like Turbo or supercharger. This system is an additional modification to increase engine power. Nitrous mounted engines are the same as engines that use Turbo or Supercharger. This underhanded or underhanded assumption stems from the nitrous system which is sometimes invisible to others. Besides the results of the power from nitrous which appears suddenly is often unexpected by the opponent.
  3. Nitrous bottles must be checked periodically to ensure the temperature and pressure are able to distribute nitrous smoothly. If needed, use a nitrous bottle heater kit to maintain the temperature of the nitrous bottle.
  4. The placement of nitrous bottles must also be in a place where there is not much direct sunlight. Like other high pressure bottles, nitrous bottles will explode if overheated too long .
  5. Nitrous can also be used on diesel cars. In fact, according to various circles, nitrous in diesel is much safer and more effective than gasoline.
  6. Excessive use of nitrous or unsuitable engine resistance can quickly damage a car engine. Therefore, consult our nitrous system with a workshop expert modification to prevent undesirable things.

Thus the review this time. To close, let’s watch a video compilation of drag cars that use nitrous.

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