Chemistry 101
Oxygen, it is not only required for humans but for the cars humans drive. The problem is air only contains about 21% oxygen. Fortunately our bodies have evolved around that and there isn't much to gain by increasing the concentration. Engines however can perform much better with more oxygen. The more oxygen that can get into the cylinders, the more fuel that can be burned and hence more energy is released as downward force onto the piston. However because the concentration of oxygen in the air is constant, and because the density of air at the Earth's surface doesn't vary drastically we have to look beyond nature to get more oxygen. Enter "power adders" or so called un-natural aspiration. Superchargers and turbochargers compress the air and thus pack more of it into the cylinders. This doesn't change the molecular composition of air, it simply raises the density of air in the combustion chamber, and thus amount of available oxygen for combustion.

The other option for getting more oxygen into an engine, and the subject

Nitrous Oxide (N20)

of this article, is to do it through chemistry. If we can increase the percentage of oxygen that enters the cylinders we have a recipe for making more power. Naturally the first idea that comes to mind is why not inject pure compressed oxygen? While a sound idea from a chemistry standpoint, practically it is not feasibile due to the volatility of pure oxygen. The next best thing is nitrous oxide, or N20. The N20 molecule consists of two nitrogen atoms and one oxygen atom. Nitrogen has an atomic weight of 14, while oxygen is 16. Thus, oxygen makes up 36% of nitrous gas by weight. Furthermore nitrous oxide is denser than air. This means that a cubic foot of the gas contains more molecules of oxygen than in the same volume of air. Since nitrous oxide is stored as a compressed liquid and injected under high pressure, the resulting temperature drop rapidly cools the air around it. This end result is more oxygen in the cylinder. So long as we up the fuel the engine will make more power.

The upside to nitrous oxide as an oxygen delivery method is that there is no parasitic drain on the motor. A supercharger requires engine horsepower to drive it. Super and turbo charging also have the side effects of unwanted heating of the air charge. Nitrous does have a down side in that it is a stored energy and hence takes up significant space. It can only be used in short bursts before the tank has to be refilled. At about $4 a pound, a 10lb. bottle of N20 can be pricey if you want to spray at every stoplight. However if you're our looking for cruise night fun or weekend track events, it is the perfect power adder.

Putting Project '01 GT on the Bottle
With the science tutorial out of the way it is time to get down to business. We decided the best way to test the effects of nitrous oxide would be to throw it on our Project '01 Mustang GT. Of the cars in the FordMuscle stable, it needed it the most. While Ford's 4.6L 2V motor is rated at 260 horsepower, the fact is the modular Mustang is a slouch compared to it's torquier and lighter 5.0L Mustang predecessor. Nitrous, unlike many other power add-ons, is pretty much self sustaining. You don't need better heads or a cam to get it to work optimally. If you set it up properly, and get the right amount of fuel in there, it is going to yield advertised gains in both horsepower and torque. This was a plus in our book as we had not performed any significant modifications on our Project '01.

There are a lot of nitrous kits on the market to chose from. You can also get hung up on the method of fuel delivery for which there are three major categories. Wet systems deliver fuel and nitrous into the intake tract. Dry systems only deliver nitrous and electronically control the fuel injectors to supplement fuel delivery. Finally direct port systems simply move N20 and fuel delivery to each port, usually using a nitrous block placed below the fuel injector. Each kit has it's merits and weaknesses, with cost generally being the biggest difference amongst the three types. Wet kits tend to run the most affordable due to less complexity of parts.

PowerWing Nozzle.

We went with the tried and true wet system from NitrousWorks. Wet systems are easy to setup, and you have straight forward mechanical control over how much nitrous and fuel is added via changing of jet sizes, akin to a carburetor. Speaking of carburetors the NitrousWorks brand is a Barry Grant company. This is evident in the quality and design of the kit. Of particular interest is the PowerWing nozzle. One of the perceived disadvantages of wet nitrous kits has been that they are "old" technology, dating back to early nitrous systems and under-carb spacers and spray bars. These systems had inherent problems with spray bars freezing up due to the adiabatic cooling effect that takes place when the nitrous oxide goes a rapid pressure change from the bottle, at 1000psi, to atmospheric pressure. Barry Grant engineers developed a better design, utilizing a hemispherical cup to facilitate atomization of air and fuel from the adjacent port.