Re: Fuel additives and H2O injection
The thing with MW50 injection - as it used to be known if you were buzzing around in a DB605 powered fighter was this - it was supposed to provide Oxygen (from the water) and provide extra fuel as well (methanol + a side order of hydrogen.
This worked fine in a 6.5:1 compression engine of something in the region of 65L displacement - but only for short bursts as even with such low compression you could mince an engine in short order. I think on DB605 engines you have 5 minutes and thats it - generally it was used as, to quote the monty python crew 'run away!!' mode..
The merlin engine as fitted to spitfires had a similar system - referred to by pilots as 'going through the gate' as you had to literally jam the throttle through a wire top-stop to engage this extra power (if the wire was broken the ack-emma or engineer would know he'd have to strip the engine and most likely do a rebuild as well, and if you kept it doing woe betide you). Six hours of pulling, rebuilding and replacing an engine for no good reason while having the living cr*p bombed out of you does not a happy mechanic make...
Now its not to say that this wouldnt work with the chengines but there is a problem.. and that is of delivery of water or whatever else you want to use. Considering that a large V8 only needs a mist of water that would be provided by the feed of a small bore surgical needle to give an effect - I have no idea what you could use to provide a feed. The water needs to be vapourised and fed into the engine with the fuel. So far so good. But too much and you will end up, in short order, with a 67cc swimming pool and not enough - no effect. Worse is an uneven delivery which would also cause problems.
Given the vibration of the engine - anything too flimsy would break and even a small bit of metal up the works at full power isnt gonna help matters any...