You hit the nail on the head. It's a weird feeling to fly a small plane and suddenly remember that there's a giant fuel tank between your legs. I don't want pure oxygen in the back seat.
When dealing with pure O2, you have to consider where it's stored
and where it's going. Basically, until it bonds with a hydrocarbon and is flushed out the exhaust, the oxygen is going to be pressurized for the entire time. A pressurized oxygen environment is an open invitation for just about
anything to blow up. Remember the Apollo 204 fire (yeah, before my time too, but maybe you've read about it)? Nobody is sure what actually started the fire, because there were so many things that could have exploded. Thanks to the pressurized oxygen in the cabin, spontaneous combustion was quite possible. Velcro, for example, was found to catch fire instantaneously. Strange but true. You could end up with burning metal, and that's a really bad thing. Who knows. Since O2 injection is not the most common thing in racing, I doubt many people know just what
could happen. Maybe your aluminum heads would catch fire and start a ferro-aluminum thermite reaction with the rusting iron block. Okay, my imagination is running wild, but you get the point.
It's very risky and unlikely that your engine (or you) would survive for long, but yeah, it's an interesting concept. So give grandma back her respirator; she'll get more use out of it than you will.
