The best link that I've been able to find is this:
water injection
I've admit I've been somewhat inspired by it.
I'm in the middle of implementing it myself so I can't comment
if it works or not. If my car was simpler it would have been done
some time ago.
Also, water boils at lower temperatures if it is in a vacuum.
Boiling Tempetrature of Water in Vacuum - Engineers Edge
In my vehicle I get a vacuum of 10-20Hg on the vacuum
gauge on the manifold which suggests the water only needs
158-194F to boil.