Easy Speed - Dispelling Myths of Adding a Nitrous System to Your Ride


When the topic is raised about easy ways to add performance to just about any automobile, whether it’s a classic muscle car, a computer-controlled piece of modern technical wizardry or even an old pickup, a nitrous oxide system is often the first answer. But even though many of us understand that nitrous is an easy and inexpensive way to add power, there are still many questions out there that scare people away from adding some punch to the ride. To help spread some knowledge, we cornered ZEX product manager Matt Patrick and asked him the questions that most of us have when contemplating adding a nitrous system.

Isn’t nitrous dangerous to an engine?
Nitrous, when properly installed according to the manufacturer’s instructions, will not damage your engine. Nitrous is still the easiest and safest way to greatly increase your engine’s horsepower. People run into problems when they get greedy, realizing how easy it is to greatly increase an engine’s power. With today’s modern nitrous systems, all that is required is approximately two minutes to change the nitrous and fuel jets that will add an additional 50, 100 or even 300 horsepower.

Beginners often try to push the window, figuring if everything appears to be running fine, a “little” more nitrous can’t hurt their engine. Caught up in the excitement, the novice nitrous user often forgets to make the proper (and safe) engine adjustments in accordance with the increased nitrous jet sizing. The most commonly overlooked adjustments include forgetting to retard the ignition timing, not changing to “colder” heat range spark plugs, and in some cases, not installing an increased flow capacity fuel pump to deliver sufficient fuel flow. The result is a nitrous system that is not correctly installed for safe operation, making engine damage inevitable. As long as the installer follows the manufacturer’s tuning instructions and advice with regard to engine adjustments and vehicle upgrades, they will have the same, reliable power gains that will not harm their engines.

I understand that you have to add additional fuel when you use nitrous, but I have no idea how much. How do I make sure the fuel flow properly matches the nitrous injected into the engine?
It’s really simple. Basically, in every kit we sell at ZEX we provide a selection of jets. Jets are just little orifices of different sizes that control the amount of flow of either fuel or nitrous. By changing the size of the jets you can control how much nitrous and fuel gets to your engine. In our kits we provide the correct nitrous and fuel jet combinations to install in sets so you always have that perfect mixture.

Does adding a nitrous system mean I automatically have to upgrade the fuel pump to get enough fuel flow?
Generally, for stock V8 applications you can add up to 125 horsepower with nitrous and still be totally safe with the stock fuel system. Start worrying when you are modifying the engine and spraying nitrous on top of that. If you increase your engine power over the stock baseline more than 30 percent or so, you need to start looking into upgrading your fuel delivery system.

But that’s a basic guideline, and every application is a little bit different. For example, Volkswagens in particular have weak fuel systems. On a four or six cylinder VW anything above 50 horsepower will require an upgraded fuel pump. But we’ve had some 5.0 Mustangs on a bone-stock motor spraying 150 horsepower without any issues with fuel. It just depends on the application. If you have a 215 horsepower 5-liter Mustang and now you are making 350 on the motor, obviously, you have used up a lot of the excess capacity of the fuel pump and will need to start looking at a higher capacity system.

Isn’t a blower or turbo safer than nitrous injection?
A properly installed nitrous system offers virtually the same level of engine safety as supercharger and turbocharger enhancements. Forced induction engine kits are usually complete packages that include fuel system and computer tuning upgrades, allowing the manufacturer to build a safe computer “tune-up” into the system. That concept is fine, but adding all those extras dramatically raises the cost of the upgrade by thousands of dollars.

With a nitrous system, the manufacturer provides the precise requirements to safely use nitrous and detailed recommendations when fuel and ignition upgrades are necessary. The beauty of this information? The customer makes the decision as to how far they can go with their nitrous systems based on their specific upgrades. A person spraying a 75 hp shot of nitrous doesn’t require a fuel pump upgrade, so why should they have to pay extra for one? But a person that wants to spray a 200 hp shot will definitely need to increase the fuel flow as well as the ignition system performance. When it comes right down to it, a nitrous system is just as safe as a blower or turbo kit as long as it’s installed with the fuel and ignition system upgrades needed for the power level you want to run.

How long does a bottle of nitrous last?
It really depends on how you use it and what your jetting is. A 50 horsepower set of jets will last you three times longer than a set of 150 horsepower jets. You really are limited by the capacity of the cylinder. At ZEX, we use 10-pound cylinders, which is the industry norm.

When talking about the capacity of a cylinder it’s important to understand that, yes, there are 10 pounds of nitrous in a 10 pound cylinder, but we are primarily concerned with what’s called liquid nitrous. In every bottle there is what’s called the clearance volume, which is the vaporous nitrous that has to be in there to properly give the nitrous in the bottle room for changes in temperature. You normally can use 70 percent of your nitrous fill as liquid. When you get below around 30 percent, any liquid that’s in the bottle will turn to vapor. You can still use the nitrous system with the vaporous nitrous, but it will make about half the power that the liquid nitrous will. So be aware that with any nitrous system you can use about 70 percent of your cylinder. A 10-pound nitrous fill will actually get you about 7 pounds of liquid nitrous.

Using those parameters with a 10-pound bottle, a 100 horsepower nitrous setting will give you about 79 seconds worth of liquid nitrous to use before you go below that 30 percent line. If you go to a 50 horsepower setting, that will extend it to almost three minutes. You can go to a 200 horsepower setting and get 40 to 45 seconds out of the same bottle.

Is nitrous oxide the same thing as nitro methane?
Nitrous oxide and nitro methane are not the same thing – not even close! Many people, especially those casual spectators of Top Fuel/Funny Car drag racing competition, think that nitrous and nitro are the same fuel. Having watched their favorite racers explode engines while making a 300 mph run down the quarter mile, they believe that nitrous also causes their engines to blow up. Nothing could be further from the truth. Nitro methane used in Top Fuel competition is a very volatile liquid fuel and only racing engines designed specifically for this fuel can handle its huge power and destructive force. Nitrous oxide is injected into the engine in comparatively small amounts and delivers smooth burning characteristics to enhance the fuel’s combustion process. Nitrous oxide can be safely used even with bone-stock engines. Whether it’s a small 55 hp shot of nitrous added to a four cylinder engine or a 300 hp shot added to a properly built V8 racing engine, nitrous allows you to add just the right amount of power without fear of damaging your engine.

I’d like to add a nitrous system, but I’m not a mechanical genius. Is this something I can handle?
At ZEX, making our kits as easy as possible to install is our claim to fame. We call our systems plug-and-play kits. We have what’s called a “nitrous management unit,” which is a little box that has your solenoids, your activation electronics, the fuel control circuitry and everything else you need. There are three wires and four hoses that come out of it, and all the customer has to do is basically plug in your fuel and nitrous, run the exit lines to the nozzle and hook up the three wires – one goes to the power arming switch, one goes to the ground, and the third goes to your throttle position sensor – and that’s it. The system will program itself and activate off the throttle position sensor automatically. I’d say typical installation time is two hours.



Optimum nitrous performance is achieved at 900-1000psi



Purge kit clears unwanted vapor from the nitrous line before racing, ensuring full nitrous power off the starting line