I have heard of this process.
Don't know the theory around it, but I do know that it has been done for about 20 years. It is simply, injecting small amounts of water vapor into the airstream along with the fuel. It boosts both horsepower and efficiency. I don't know about the copper line to the carb thing though. I heard it has to be injected (water does not vaporize as easily as gasoline). Ever notice that a very humid rainy day that the car runs better. I am from a very dry climate, and a little moisture in the air makes a noticeable difference. Same thing.

If anyone has an article on this process, please post it.

Curtis