[Warren_from_PINZ]

Hi, I'm new in here but I thought I'd post my 2 cents worth... (I have a degree in Physics).
There's been quite a bit of debate about where to inject it and I'd go with those that have actually tried all the possibilities and measured the results. I would expect that you'd get a better result from going after the IC because the IC won't have as much work to do if the incoming air is already "cold". In other words the amount of heat the IC will take out depends on the difference between the cold air coming in the front of the car and the hot air going through the IC. So that suggests not to put a nozzle before the IC so the iC can do its thing first.

On the other hand, if you're drag racing, for example, it might be handy to have a nozzle before the IC just to cool the IC down before you get the green light.

As for putting it before the turbo compressor, I can tell you that if the water is introduced in a stream instead of a pulverized vapour you can get notches on the compressor wheel. I know... I did it. I'll try to get some photos of it. But whether a fine mist would do the same I don't know for sure. I'd be surprised if it did but I haven't tested it.

After much discussion, there seems to be a general concensus that injecting before the compressor should move the efficiency islands towards the higher flow rate of the compressor map, ie. you would get maximum efficiency at a higher flow rate. Has onyone tried this?

Cheers