Nitrous Oxide in Cars: What Is It and How Does It Work?

If you’ve ever watched movies like Fast and Furious, you’ve probably seen actors flipping a switch or turning a knob that makes their vehicles go extremely fast during high-speed chase scenes.

While the movie is pure fiction, there are real upgrades featured in the story that can boost your vehicle’s power. One example is by installing a nitrous oxide injection system on your ride.

What Is Nitrous Oxide?

Nitrous oxide (N₂O) is a colorless and non-flammable gas that consists of two nitrogen atoms and one oxygen atom.

When used in an engine, nitrous oxide can produce a short burst of power, usually between 50 and 150 hp.

Nitrous oxide is a power adder that’s typically used for racing and high-performance driving. Compared to other engine power adders, nitrous oxide is a cost-effective alternative to generating more horsepower.

Discovered by Joseph Priestly along with oxygen, nitrous oxide is a manufactured gas that requires a catalyst. This means that nitrous oxide can’t burn on its own.

How Does NOS Work?

A nitrous oxide system (NOS) typically requires nitrous oxide to be stored in a pressurized container and held at an angle that will keep the pickup tube inside the liquid. The discharge end of the container should be toward the front of the vehicle.

Nitrous oxide also requires about 11 lbs. of pressure per degree Fahrenheit to be condensed into liquid nitrous oxide.

Activating a vehicle’s NOS can be as simple as flipping a switch. This switch usually activates a pair of solenoids that will kickstart the entire process.

Once nitrous oxide is injected into the engine, it turns into gas and supplies more oxygen for fuel combustion.

Metering jets distribute amounts of nitrous oxide and fuel into the cylinders via an injector or nozzle that’s linked to the intake manifold or piping.

Types of Nitrous Oxide Systems

There are generally two types of nitrous oxide systems: wet and dry. The type of system an engine needs depends on whether or not additional fuel is supplied at the same time as nitrous oxide is released.

Wet System

A wet NOS will require additional fuel to be injected into the cylinders. This system usually has a red and blue nozzle, with the red flowing gasoline and the blue flowing nitrous oxide.

Dry System

A dry NOS is usually found in engines that use port fuel injection. In this setup, only nitrous oxide needs to be injected. This is because the powertrain control module (PCM) can automatically command more fuel to be injected when nitrous oxide is being sprayed.

In a dry NOS, air and injected nitrous oxide are the only elements found in the intake manifold.

Shot Rating in Nitrous Oxide Systems

Nitrous oxide systems sold in most shops will usually contain a shot rating.

Shot rating refers to the estimated performance increase in an engine. For example, if you have a 50-shot kit, the horsepower boost you’ll be getting from that kit will likely be around that number.

Keep in mind, however, that the actual horsepower added to the engine can vary with the addition of nitrous oxide, depending on factors like engine configuration, bottle temperature, and bottle pressure, among others.

Is NOS Bad for Your Engine?

A nitrous oxide injection system can damage your engine, but only if you fail to follow the right steps and protocols for installation.

Otherwise, you’ll be able to enjoy the pros of having an NOS, such as affordability, easy installation and disassembly, and traction control benefits for high-power drag cars.

Engine Prep for NOS

When integrating nitrous oxide into a vehicle, its engine needs to be able to withstand the immense heat and pressure that will occur in the combustion chamber because of the manufactured gas.

For the engine to accommodate the nitrous oxide in its system, you’ll need to switch to forged pistons. These pistons can handle the extreme pressure and temperature that comes with pumping nitrous oxide.

It’s also important to increase the cylinder wall-to-wall clearance. In an NOS, piston temperature tends to increase because of the additional fuel and nitrous oxide.

Lastly, most experts recommend switching to a forged crankshaft and connecting rods.

Installing and  Calibrating a Nitrous Oxide Injection System

Buying all the components of a nitrous oxide system is fairly easy, mainly because they’re sold as part of an installation kit.

In most cases, there are different sizes of nozzles included in the kit, so the driver can choose which one is best suited for his vehicle. 50, 100, and 150 hp are the most common calibrations for the nozzle sizes.

A typical nitrous oxide system kit also comes with an on-off switch and a different switch that’s placed near the throttle. This switch will activate the system when the throttle is fully opened.

Is Nitrous Oxide a Street Legal Upgrade?

Regulations about the use of nitrous oxide in vehicles largely depend on the state you’re driving in.

It is, however, a common belief that the federal government doesn’t consider nitrous oxide as an illegal upgrade, but some states impose restrictions on nitrous oxide use.

Where to Spot Nitrous Oxide-Infused Vehicles

Nitrous oxide is primarily intended for the tracks or in drag racing events.

States that permit this setup often prohibit nitrous oxide from being used on the streets. Some states don’t allow vehicles to be fitted with nitrous oxide tanks even when they’re not in use.

Do You Really Need a NOS?

Nitrous oxide is certainly a cost-effective upgrade for those who want their vehicles to pack a punch when on the tracks.

This manufactured gas is primarily intended for vehicles that have undergone engine modifications to withstand the extreme heat and pressure that come with such an upgrade.

It’s also important to keep in mind that nitrous oxide only provides a temporary power increase and shouldn’t be treated as a long-term upgrade.

If you’re not into racing, there’s not enough reason to install an NOS on your vehicle.