I made the consumption of water with the spraying 3dl to 100 I would like to spend 5dl env for that I will mix the turbo pressure in the water tank and use the accumulation of air to spray in deceleration mounted with a non-return valve between the turbo and the air water tank
this summer i tried spraying water with the perfume sprayer, for lack of time it was not as expected
I doubt your windshield washer pump will last long
an other idea ! use a tank half water half air inflated to the right pressure, you will empty your water without losing too much air pressure, a perfume sprayer with an electro valve
or a motorhome pump with built-in pressure switch (1,8 bar max)
http://www.top-accessoires.com/index.php?cPath=40_73
pitmix! with your golf you encouraged me to resume testing on the vito