I knew of the water-injection of the WWII Corsairs, but did not know of water-injection in cars.
Interesting stuff. I've seen a couple variations of this on TV involving water injection and hydrogen & water induction systems. It was all politically shelved as well. Bet we'd all love to see where it winds up 75 years from now.
Years ago I read about a man in Florida who successfully developed a means of doing doing this and in the article it said he was scheduled to meet with government officials to discuss his project. There was never a follow-up article, as had been promised, and I didn't see his name mentioned, again. There are kits for doing this and some say they have had success with the kits. I haven't tried one and I can't in Germany, where they do not allow any deviations from the original manufacturer's design. You even have to get permission to add a sport steering wheel, or change the rims on your car, and don't even think about adding any fog lights to your car that were not original. The fines for failure to comply are excessive. When I arrived I had to take the trailer hitch off the back of one of my cars because it 'wasn't Germany certified.'
I think there was a time when Honda was investigating Hydrogen/water vehicles in California. Never heard a lot about it, and I am sure it got shelved as well.