Re: Would pure oxygen increase horse power or output of a combustion engine?

Essentially, pure oxygen would give more horsepower to a gasoline engine 
because it is not diluted by nitrogen like it is in air - to a certain 
point (RPM).  The ignition timing of a gasoline engine is optimized for 
running in diluted oxygen (air, which is mostly nitrogen).  You would get 
significantly better horsepower only at low RPM, where the burning time of 
gasoline at 8 or more atmospheres is not critical.  However, most engines 
are designed to have optimized power in the 2500 to 4500 RPM range.  At 
high RPM, gasoline would burn too quickly and you would loose power.  The 
ignition characteristcs of the engine would have to be completely 
re-designed and re-thought out from scratch for burning in pure oxygen.  
Other oxidizers, like nitrous oxide, supply roughly the same ratio of 
nitrogen to oxygen but are more reactive than air, which is why nitrous 
oxide supplies so much more power at high RPM - i.e., the burning rate is 
unchanged but the ability to supply oxygen on demand is better than with 
air.