Question: What is Nitrous? Will it make my car go faster?

NITROUS OXIDE ( Laughing gas )
In a car it is no laughing matter - - -The combustion process could be described as a rapid oxidization of fuel. To get the process started we mix air and fuel at a rate of about 14 pounds of air for every pound of fuel and we introduce a spark that starts the rapid burning process the reason for the air fuel mixture of 14:1 is that there is enough oxygen in this quantity of air to combine with the fuel elements to support the "burn ". Higher oxygen levels make for a more efficient burn, and that makes more horsepower.

The problem is that pure oxygen is very dangerous to handle. For instance pure oxygen and grease coming into contact with each is a recipe for an instant explosion!  So the thing is to introduce oxygen in a safe state: Oxygen combined with nitrogen as Nitrous oxide gives the additional oxygen for more effective combustion (more horsepower) with safe handling characteristics. Adding Nitrous to an engine is like drug doping a horse or an athlete. Increasing the dosage has increased effect just like performance enhancing drugs on the athlete. More is only better up to a point where adverse side effects start surfacing. 

Inside the engines combustion chamber there is only so many fuel molecules to oxidize -- so when there is not enough fuel for the amount of oxygen present anything that will oxidize or burn becomes fuel, like for example engine components. In other words too much Nitrous can be disastrous to an engine unless there is a provision to introduce additional fuel to match the oxygen levels that could be attained in the combustion chamber. Another drawback is that the Nitrous has to be contained in an onboard pressure vessel which tends to limit capacity. Generally it gets most of its use as a performance enhancer on the drag strip as it is a legal addition to some classes of drag racing. It also sees some use at stoplight "Grand Prix" events