Use it before going on a long hard country lane drive. Gives a bit more help to keep the intake temps down and it does work. Very rairly use it when driving along as most of the water will just get blown of the i/c due to the airflow through it.
Auto version is the way to go, as charge temp's get to hot or to high,for arguement sake 40 degrees then the Ecu or apexi will atuomatically
bring the Water injection/spray on!! so your engine doesn't retard ignition timing,some tuners don't like water injection, but I know that it also helps a to stop detination to an extent,,just from experience
funny you should talk about this been talking about this very thing today rs components do a 12 dc timer unit £20 all you have to do is wire this in simple to do in ten mins and then you can set the water spray from 10 secs to 6 mins simple and very cheap to do . worth it for the summer ..
...or if you don't mind a bit of wiring you could spend about £39 (plus courier) and get the fully auto Autospeed jobbie that monitors the IC temps, learns your use of the car then predicts when to spray the intercooler and for how long. The fully boxed, wired version inclusive of 2-5 day DHL from Oz is £98.55. Add on a couple of decent spray nozzles that Autospeed do to replace the standard Evo dribblers and you get a decent kit for £121 all in.
I can obtain nozzles in the UK if I find them necessary , same goes 4 the pump except I wouldln't buy the ERL due 2 cost , I wud use a large flow pump from a headlight washer system off a Porsche (they r good 4 something ) or wotever.
I know every1 thinks the stock nozzles r crap but u need 2 remember that when the car is moving the airstream will atomize the spray , anyway we'll c.