For what it's worth department:

Water added to fuel under the right conditions and in the right way is a
plus.

During WWII the Corsair aircraft engines had a water injection system.
When the situation warranted, the pilot could achieve "military Power",
  slightly above rated power, by going to full wide open throttle. This
would activate the water injection system. Apparently the addition of
the water enhanced combustion to develop the extra power for
emergencies. Possibly by reducing heat, or changing the burn pattern to
enable greater power, ot maybe something else from a theory standpoint.
I don't know. I just know that it was done, and it worked.

Jophn Rodgers
88 GL Driver