Say the words “nitrous oxide”.

Some people will think of jabbing a button and leaving your spleen behind as massive acceleration shoves you back into your seat. Others will think of shattered con rods, mangled pistons and huge repair bills. (Some might even think of yellow balloons and laughing fits, but that’s for another blog.) Here at the Atomic Labs we just love the stuff.

Nitrous oxide (N2O) was discovered by Joseph Priestley in 1772, and in the 1790s Humphrey Davy tested the gas on himself and some of his friends (hmm, what’s this stuff? I know, let’s sniff it…). The first practical application of N2O was as a medical anaesthetic and painkiller. The German Luftwaffe experimented with nitrous engine injection in World War II, which allowed their planes to fly higher than previously possible. But with the advent of jet engines, the project was shelved. After some stop-start forays into motorsport, nitrous became mainstream in 1978 with the formation of Nitrous Oxide Systems Inc.

Enough history. So how does it work? First off, nitrous is not the engine-destroying monster as many people believe. When installed properly and used sensibly, there is little or no engine degradation. And by itself, nitrous oxide is *not* flammable or explosive. That scene in The Fast and The Furious when the car explodes in greenish flames is Hollywood crap.

(Chemistry warning!) Okay, we all know what nitrogen is. Most of the air we breathe is made up of nitrogen (N2). Take nitrogen and add an atom of oxygen to the molecule, and you have nitrous oxide. This new molecule is pretty unstable, and wants to return to a nice stable N2 by getting rid of that oxygen. When heated to 302 degrees C, the nitrous molecule breaks apart, giving off the oxygen atom and reforming N2. So for every 2 N2O molecules that break up, you get two N2 and two oxygen atoms, which join up to form an O2 oxygen molecule.

In a car’s engine, fuel is burned with oxygen (O2) to create power. When nitrous is injected into the engine, additional oxygen is released from the reaction above – allowing more fuel to be added which produces more power. Simple as that. As an added bonus, when nitrous is vapourised its temperature drops hugely, cooling the intake charge which makes it denser, allowing even more oxygen to flow into the cylinder.

There are 3 types of nitrous systems, but all achieve the same effect at the end of the day. Dry systems supply N20 into the intake airstream with a single nozzle, and rely on the existing injectors to add the additional fuel required. Wet systems supply extra fuel along with the N20 gas. Lastly, direct port systems add N20 and fuel into each individual cylinder, with nozzles installed between the intake plenum and cylinder head. Direct port systems can add up to 500hp or more…

There you have it. Now can you resist the temptation to go out and buy a bottle of instant power…?

Questions? Comments? Requests? -> tachyon (at) carblog (dot) co (dot) za.

(C) 2006