The key is a large area to discharge into, and also to have a bit of pre swirl of inlet air, this combined with low particle size for your droplets and you will have excellent performance (at very high water flow rates as I and my customers use) and non visible long term effects on the compressor wheel.
You can see the RX2 in this video
http://www.riceracing.com.au/Videos/...-injection.wmv and you will see one of my jets located on the back of the compressor cover pointing into the air filter void and against the oncoming air stream. This 13B engined car makes 600+rwhp (over 750bhp) on Optimax 98 Ron pump petrol and uses around 600cc/minute water flow rate. It has consumed well over 200lt of water and the compressor wheel looks just like a new one
