"First off, nitrous alone will not make you Mustang fly. Instead, it helps you engine make additional power by adding oxygen to the combustion process. Torque (and horsepower for that matter) is created by burning the air/fuel mixture efficiently in the cylinders. When gasoline is atomized, mixed with oxygen, and burned in the combustion chamer, the result is a release of great enery and tremendous cylinder pressure that pushes down on the pistons and rotates the crankshaft. And so, if you can get the engine to burn more fuel and oxygen, it can create more energy and thus more power. To efficiently burn gasoline it takes oxygen and a spark. Only then can we complete the combustion process. While fuel is pumped in by the fuel system, the oxygen comes from the atmosphere and therefore it's less controllable, and that's why it is harder to tack more oxygen in the cylinders. The air we breathe is actually a mixture of 72 parts nitrogen, 23 parts oxygen and about five parts unknown gases. But it's only the oxygen content that our engines use for combustion. If you want to get technical, we'll tell you that for every cubic fot of air, only about 21 percent is oxygen. With nitrous, the percentage of oxygen per cubic foot increases to about 50 percent. That's why some call nitrous "atmosphere in a bottle". To make maximum power, your engine needs to have the correct air/fuel ratio. If the ratio is altered due to a rich or lean mixture, the engine will be less efficient. In extreme situations, an excessively rich or lean condition could result in damaged parts. Naturally aspirated street-type engines operate with appoximately a 14.7:1 air/fuel ratio. However, in racing it's common to have a slightly richer air/fuel ratio, such as 13:1. When a power adder is used, the ratio may be necessary to go as rich as 12.5:1 or lower. That's because with power adders comes increased cylinder pressure and with that comes increased heat. Adding fuel actually keeps the combustion from getting too hoot, which helps prevent detonation. Over the years, there have been great advancement in nitrous technology; however, there are still only a few different ways to deliver the spray to the engine. These systems include dry systems, wet systems, port systems and plate systems. And despite the differences between them, most kits operate similarly. A typical kit will have a nitrous bottle, fuel and nirtous lines, solenoid(s) and either nozzles or a plate to spray the nitrous and fuel into the manifold. Most kits also include electrical connections to energize the solenoids and a switch to activate them. With electronic fuel-injection manifolds, it is common to run a "dry" nitrous system. Having a dry system simply means no gasoline flows through the intake manifold, even though the nitrous is injected at the throttle body. In a dry system, the additional fuel is added through the fuel injectors. This is done to prevent gasoline from puddling in the manifold as it tries to turn the sharp corners found in many stock-type manifolds. Puddling is very bad for two reasons: If the fuel is puddling it's getting to the cylinders, and secondly, is a valve hangs open, the fuel in the intake can explode and blow the intake right off the car. In contrast to the dry system is the "wet" system. Wet systems inject the nitrous and fuel at the same point, usually directly under the carburetor or at the throttle body on tunnel ram style intakes. Wet plate systems are very popular because they are simple and usually easy to install. The third type of system is called direct-port nitrous, the nitrous and gasoline are injectedby a common nozzle mounted directly into the individual ports in the intake manifold, usually at a close point to the cylinder head. A benefit of direct-port nitrous injection is the ability to fine tune individual cylinders. Most of you know that superchargers and turbochargers add performance by pumping air into the engine uder pressure. It's also common knowledge that naturally aspirated engines rely on the negative pressure created in the cylinders to draw the charge of air and gas into the chambers. The beauty of nitrous oxide is that it can add power to any of these engines by adding pure oxygen to the cylinders. The difficult part of adding nitrous is tuning the flow of nitrous and the proper flow of fuel to the engine maintains the proper air/fuel ratio. With today's huge electric fuel pumps, fancy regulators and large lines, we can flood the engine with fuel if necessary. But dialing in the right amount of nitrous oxide is a bit more difficult. Fortunately, there are many levels of nitrous kits available so you don't need a degree in mechanical engineering to get going. Usin nitrous oxide is not rocker science, but there a few basic rules to follow. By now you realize that nitrous has a tremendous and instant ability to produce huge power gains. Nitrous also causes sylinder pressure to rise and with that comes lots of heat. As with any power adder, excessive heat can lead to pre-ignitiong, detonation and severe engine damage. So, let's start with some basic rules of the game. Rule number one is to be smart. Read the instructions and follow the recommendations of the manufacturer or an experienced installer/tuner. Second, use only the spray when the engine is in top running condition and use it in a controlled environment. If you've been driving around on a 100 degree day and the engine is cooking, that's a bad time to make a 20-second nitrous blast, even if it will impress your new girlfriend. Being smart also includes staying aware of your gauges and treating your car with respect. Next, be sure to have the proper octane gasoline. The octane rating determins the gasoline's resistance to detonation or spark knock. Gasoline with a high octane rating burns (or evaporates) slower than a low-octane gas and this is absolutely necessary in the oxygen-rich environment of a nitrous engine. Our tip: if you're using a 50-125 horsepower kit, and the engine timing is set properly, you can get away with 92-94 octane gas. Beyond that we suggest using race gas. Nitrous oxide has great power-making potential, but the "shot" or horsepower level you decide to use must be tailored to the capabilities of you engine. The nitrous used must understand that as power levels rise, the strain on the internal parts increases. Racing engines producing over 400 horsepower will require special preparation. We all know that stock 5-liter engines can handle quite a bit of abuse, but they won't tolerate detonation very long. If you're new to the nitrous game we recommend starting with a small (50-125 horsepower) shot, and then set the timing to 10 degrees (with EFI). With carburation, back the timing off about two degrees per 50 horsepower of nitrous. Thankfully, most 5-liter and 4.6 engines can handle these smaller nitrous kits without any modifications. Still, be smart. Always run the high-octane pump gas and start with a small test squirt. Make a 300-foot run and check the plugs. If they look clean go another 300 feet. Remember, the longer you stay wide open, the larger the load on the engine and the hotter things get. Be patient and finally you'll be running to the end of the track with the juice flowing. (Note: This test can also be done on a chassis dyno.) A burned spark plug electrode is a clear sign of detonation. Another sign of detonation comes in the form of black dots and a greenish tint. A "clean" plug will show light brownish coloration and the electrode will be in perfect conditioin. We also recommend that you check all the plugs, because different manifolds will distribute the fuel and nitrous differently to each cylinder and will cause some cylinders to run leaner than others. And when tuning the juice, always tune for the leanest cylinders. In addition to learning the basic tuning procedures, it's also important to know the limit of your engine's internal components. As you increase the level of nitrous, you must also increase the strenght of the engine parts. While stock rods and pistons will work with a 125-175 shot, a 250 shot normally requires stronger rod and main cap bolts, forged pistons, a stronger crankshaft, and aftermarket connecting rods." 5.0 4.6 Tech Guide", from the editors of "Muscle Mustangs & Fast Fords". If you want more, i can always finish the article, because that's about half of it