Active Nitrous Systems - History of NOS

A quick history lesson

It was during the Second World war that it was discovered that by injecting nitrous and a proportionate amount of fuel would generate almost endless horsepower increases, the only limiting factor being the mechanical limitations of the power plant. From the 1960`s to the present day drag racers have embraced the idea of injecting nitrous into their engines. Nitrous provided huge power increases at a modest cost with controllability and reliability.

Nitrous oxide is a substance that comprises of one part oxygen to two parts nitrogen. It is not poisonous or harmful to the environment. Under normal atmospheric conditions nitrous oxide must be kept under pressure to remain in a liquid state. To convert nitrous into a gas is a simple operation of releasing it into the atmosphere.

Ok, so how does it work?

The chemical properties of nitrous oxide make it an almost perfect catalyst for combustion. Nitrous quickly expands from a liquid to a gas when released into the inlet tract absorbing a massive amount of heat as it changes its state, this refrigeration process cools the inlet tract, which dramatically increases the density of the inlet charge. You may notice on a cold frosty morning that your engine seems a bit more responsive, this is due to the charge temperature being cool.

By injecting nitrous oxide into your engine you are introducing a cool, dense, oxygen rich inlet charge just ripe for combustion. But this charge will not burn on its own so additional fuel will need to be introduced in the correct ratio. The dense, highly concentrated air/fuel charge increases combustion pressures as it burns, which as a result transfers huge amounts of energy to the engines crankshaft, this equals more bhp.

Types of nitrous systems

Wet, dry, direct port or plate systems – which is best?

Here at Active Nitrous there is no answer to the above question. What it comes down to is which type of system is best suited to your vehicle.

The differences between wet & dry systems are that in a wet system nitrous & extra fuel are injected into the inlet tract through a common nozzle. In dry systems nitrous oxide only is injected into the air intake. The additional fuel has to be provided by enriching the jetting of the carburetor or by increasing fuel pressure, altering injector duty cycle or by fitting bigger injectors.

In direct port systems Nitrous oxide and extra fuel are injected into the intake ports through individual nozzles and jetted on a per cylinder basis.

Finally plate type systems are for engines fitted with carburetors, these are systems where nitrous is injected into the inlet tract via a plate mounted between the carburetor and the inlet manifold. The plate has two brass tubes, one positioned above the other. The upper tube is usually the nitrous and the lower the fuel. The higher velocity of the nitrous as it is vented helps to atomize the fuel in the manifold.

We feel that for road use a wet system is suitable for the majority of cars, because when the system is not in use the engine is ignorant to the fact that nitrous is installed. This is primarily because the oe fuel system remains unaltered.

Dry systems do have their place on road cars but usually on engines where the inlet manifold is a dry flow type. This occurs mainly on American engines ie GM`s tuned port injection engine which has a port injected fuel delivery system. The inlet manifold is not designed to flow fuel and air, this can cause fuel drop out and puddling. Though not normally a problem when an oxygen rich inlet charge is introduced a normal backfire can cause detonation in the inlet manifold, sometimes with dramatic results.

If you are unsure what type of nitrous system is most suitable for your application click on the product picker link in the menu at the top of every page.

Nitrous Oxide History

A quick history lesson

Ok, so how does it work?

Types of nitrous systems