Nitrous is perfect for those “Dude, I almost had you” moments when you need just a little extra power. Nitrous kits can be installed in just about any type of vehicle and are less costly than adding a supercharger or a turbo system. If you’re new to the idea of purchasing a nitrous kit, it can be overwhelming, and you may be unsure of where to start.
Used in internal combustion aircraft engines during World War 2, Nitrous Oxide was mixed with aviation fuel to boost performance at high altitudes where the air is thinner and less oxygen is available. But its history goes back to 1772, when it was inhaled as a recreational activity (hence the name laughing gas) and then as an anesthetic. Today, it is most commonly seen in racing applications and treated as an off-highway, racing component not for use on public roads as its legality varies from state to state.
Nitrous is often seen on naturally aspirated engines and can be used on boosted engines. It has become a popular application to help spool the turbo quicker with the ability to shut off at a certain boost pressure.
So what is Nitrous Oxide is, and how does it make power?
According to Matt Maxwell from ZEX, Nitrous Oxide, N2O, is a gas composed of two nitrogen atoms bonded to one oxygen atom. When nitrous is injected into the engine while initial combustion takes place, it creates enough heat to separate the nitrous oxide into its two components nitrogen and oxygen. Once separated, the extra oxygen is then free to react with the additional fuel. Maxwell added that burning more fuel creates higher cylinder pressure that pushes down the pistons with greater force (measured as Brake Mean Effective Pressure or BMEP) thus producing more torque (horsepower being a calculation based on torque and engine speed).
Here is what you need to know before purchasing your first nitrous kit:
Is nitrous safe to install on my daily driver?
Maxwell: A properly installed nitrous system is perfectly safe for a daily driver, but it really comes back to the legal issue, which depends on your state. Nitrous should only be used in short bursts. We do not recommend using it for longer than 15 seconds at a time.
How long will a bottle of nitrous last? Will it explode if I leave it in the car?
Maxwell: A good rule of thumb is 0.8lbs of nitrous oxide is used on a 100hp shot for 10 seconds. In other words, you could run a 100hp shot for a total of 125 seconds to run the bottle out of nitrous. The performance starts to drop off as the bottle gets closer to empty. Most serious racers keep a few full spare bottles on hand and swap them out when the one in the car is down to about 4lbs, or they notice that the power has started to fall off.
“You won’t have to worry about nitrous freezing, but a cold bottle hurts performance. Nitrous works best between 900 and 1000psi, at around 85-90 degrees Fahrenheit, which is why a bottle heater is one of the best accessories you can buy. It keeps the bottle up at the proper temperature for the best performance.
However, as bottle temperature rises, the pressure inside increases. Properly made nitrous bottles have a pressure safety disc that releases the gas before it gets to an explosive level.
That said, releasing all of your nitrous to the atmosphere is a real bummer. When temperatures outside range from 80 degrees to 100 degrees, the temperature inside a car parked in direct sunlight can quickly climb to between 130 and 172 degrees. The best bet is to park in the shade with your windows cracked or bring the bottle inside when the outside temp gets above 80 degrees.
What’s the difference between a wet or dry kit, and how can I figure out what is best for me?
Maxwell: A dry system uses a nozzle to spray only nitrous oxide into the intake manifold. A wet system uses a nozzle to spray a mixture of nitrous oxide and fuel into the intake manifold. In general, if your car has a returnless fuel system, then you need a wet nitrous kit. Most cars, since the late ’90s, have returnless fuel systems, so wet systems are the most common choice.
What is a “shot” and how do I determine how much I need?
Maxwell: A “shot” is typically how much horsepower the nitrous system is adding to the engine. For instance, a “hundred shot” is adding 100 flywheel horsepower on top of what the engine makes normally. The horsepower level of the nitrous kit can is easily changed by swapping out metering jets. Most nitrous kits have multiple jets or “shots.” At ZEX we offer kits that start as low as 35hp and others that go as high as 450hp.
Determining how big of a shot you need, depends on how much the engine components are capable of handling, and how much more power you need to achieve your performance goals.
What are the most important things to consider before purchasing a nitrous kit?
Maxwell: There are several things to consider, such as:
- How much horsepower increase can the engine handle? A large V8 can handle more horsepower than a small 4 cylinder engine.
- How much power increase can the fuel system handle? A supplemental fuel pump may need to be installed.
- How tune-able is the ECU in the car? Higher horsepower levels may require tuning, such as ignition timing retard.
Your nitrous kit manufacturer, like ZEX, can help you figure out the answers to these questions.
Should I upgrade any other components when I add a nitrous kit to my car?
Maxwell: This can vary from car to car. So it’s best to ask a nitrous system manufacturer to see if your car requires any special equipment. A nitrous kit includes all the necessary components required to function, but there are some accessories, such as a purge kit or bottle heater, that enhance the system.
Is it hard to install?
Maxwell: Installation is not very difficult, and ZEX includes very detailed instructions. A performance shop should be able to install a nitrous system in about 2-4 hours. An enthusiast working in his driveway or garage should be able to install it in a Saturday. Only essential tools are needed, such as a screwdriver, adjustable wrench, wire stripper/crimper, and hand drill. It is also a good idea to have a voltmeter on hand to check electrical circuits.
For more information on nitrous kits, see the ZEX website.