I have been watching this thread with some interest. I'm beginning to become inspired to do a little testing. Currently I am only using one of the TEC3r's (
www.getfuelinjected.com) mapable outputs to map WI (using Aquamists 2C system), with 2 nozzles post IC. I have another spare mapable output - and I'm beginning to think that placing another HSV in a line supplying a pre-compressor nozzle might be a worthwhile experiment. This would enable me to play with the water delivery and compare results of varying switch on points and delivery amounts independently of water that is being delivered post IC.
The only thing making me think twice at present is I am running a Garrett Disco Potato turbo (GT28RS, 0.86 AR compressor 76 trim, 0.64 AR turbine 62 trim) - so it is if anything oversized for a 1.6L engine making 280bhp (sized for future plans).
Worth making the effort? I have full data logging software that will allow repeatable power/torque graphs to be plotted if using the same stretch of road.