Folks,
  I was a KC-135 crewchief from 1982 until (military) retirement in 2003.  I
worked in KC-135A's and -Q's with the 13,700 lbs thrust Pratt and Whitney
J57 water-injected turbojet engines.
http://www.globalsecurity.org/military/systems/aircraft/systems/j57.htm
  670 US gals of distilled water is injected only during take-off to
increase thrust; E=MCsquared (increase of a mass accelerated = increased
thrust output for a given engine).  That's exactly how and why a
turbosupercharger works, but much more pronounced.  By packing more
molecules of air/ fuel/ water vapor (to a limit) per power stroke more mass
is accelerated, creating more power.  BTW, I also worked on RC-135 V/W's
(with J57's), KC-135E's (with TF-33's) and KC-135R's (with CFM56's), not to
mention some time as a jet mech on F-15A/B's (with F100's).
   This basic priciple of physics applies to ALL engines, including
reciprocating engines like those in our Vanagons!
  When I was stationed in Okinawa ('82 - '85), I rigged a homemade water
injection system on my '70 VW Squareback with dual carbs.  I can describe
exactly how to anyone interested.
   It does two things; it quenches pre-ignition in a reciprocating engine
(preventing engine knock/ ping to eliminate detonation from pre-ignition by
cooling the charge in the cylinder.  It also, will augment thrust output
(HP) a small amount, but in an under-powered vehicle every little bit helps,
when you need it.   Obviously, this has its limits both in amount and
duration applied.  Too much quantity and you'll quench the combustion
completely. Too long and you'll use up your limited supply onboard.
   It was nice to be able to hear engine ping starting, then press the
momentary switch that I'd mounted on my automatic's shifter, and apply water
just long enough to overcome the uphill load situation that was causing
detonation.
  I think it's time to experiment with this age-old technology, to see if it
helps the Vanagon engine........

Mike B.

Subject: [SPAM] Re: Water Injection

> Definitely, the engines that had trouble water getting into the combustion
> chamber, had their insides immaculately clean and the cooling was great.
> Zoltan