http://youtu.be/NFU6KrSOe8U
This is new to me. I just found this last night.
Pre-turbo has always been generally a "bad idea". Water droplets can actually damage the compressor blades over time. But I guess some guys have found a happy medium.
Kind of odd though. I personally would prefer to avoid humidity (moisture in the air). It makes the air heavier. That's why you go the fastest in cold, dry air. So kind of weird to me to purposely inject water before the turbo. In one forum or another, the turbo has to pump that air/water. Only thing i can figure is that it removes so much heat that its worth the added weight to the air.
Either way, that is an awesome idea. Its basically using boost to pump the water into the turbo and using a nozzle to break the water up at the injection point ( like nitrous does to fuel at a wet kit fogger nozzle, only fuel is 50-100psi and nitrous is 900-1200psi ). The water coming out of the nozzle is running at a pressure below what ever your boost is. Then the nozzle necks the pressure down blows the water apart to mist it.
The pre-turbo setup is pretty much nothing compared to what a real water/meth system pumps in.