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No Laughing MatterI was wondering why nitrous oxide is used instead of pure oxygen in nitrous-oxide systems. Nitrous oxide has two nitrogen atoms and only one oxygen atom per molecule. The nitrous-oxide molecule must be broken apart so the oxygen atom can combine with another oxygen atom to form O2 before it can burn, so why not skip that step and use pure oxygen (O2) instead of nitrous oxide? Much smaller gas-injection jets would be required compared to the fuel jets, of course. Why don't companies do this? Would pure oxygen produce "unpredictable results." Nolan HeinrichsSwift Current, Saskatchewan, Canada
The results with oxygen are actually quite predictable: You'd blow yourself up. But we can be a little more specific. Nitrous oxide itself is not a fuel; it adds power to internal combustion engines by allowing them to burn more fuel. As you know, one of the primary goals of performance-tuning internal combustion engines involves stuffing the combustion chambers with as much air as possible. Conventional means of accomplishing this include porting cylinder heads and using higher-flowing intake manifolds and greater-duration camshafts to improve the engine's volumetric efficiency, thus allowing the engine to "inhale" more air on each intake stroke. External means are also used to force-feed engines, as with superchargers or turbochargers. Filling the combustion chambers with more air allows the engine to burn more fuel, and therefore, make more power.
That brings us back around to your question. An obvious answer might seem to be the injection of pure oxygen, since that is, after all, what we're trying to accomplish with all of the previously mentioned methods of improving power output. Oxygen enables combustion, but introducing pure oxygen to the air/fuel mix would make that combustion much more difficult to control. Nitrous oxide, on the other hand, requires the heat of combustion to separate its molecules, which means that the pure oxygen molecules we're looking for aren't released until we actually need them. Of course, this additional oxygen requires additional fuel to maintain the desired air/fuel ratio, and all nitrous systems have some means of accomplishing this, either by adding fuel with additional feed lines and spray nozzles, or, in the case of some EFI systems, by increasing fuel pressure in the engine's fuel rails, which causes more fuel to be delivered with each pulse of the factory injectors. If you're looking to inject more horsepower, look into nitrous oxide and leave the pure oxygen to the medical professionals.
Fox HuntI enjoyed the article on the Fox Mustang ("5.0L Mustangs: The Next '69 Camaro," Feb. '03) and would like to know if the Mustang and the Thunderbird are the same design. I have an '87 Thunderbird lying dead in the yard and would like to bring it back to life. All of my experience is with GM cars, but the T-bird was rust-free and only $350. I want as much street performance for as little cash outlay as possible. Tom WhitakerWolf Lake, IL