Injecting prior to turbo comp' impellers

[Macabre]

Originally Posted by b_boy

For the sake of arguement let's say we could "recover" all the energy lost to heat at these near maximum speed. We could realize a 50% increase in compression with no heat loss. Effectively, our turbo would be 50% larger. That is a major accomplishment for the injection of a little water.

I've read through this thread, and this statement is really the crux of what's being discussed here. However, what I have not seen is any evidence or argument to suggest that this effect would be any different from the heat absorbtion that occurs when injecting water after the compressor. I.e., that it isn't accompanied by a proportional drop in pressure. I don't mean to be challenging, just looking for an explaination if there is one. It seems to me that there is a fairly large logic leap involved in the supposition that injecting water at the compressor inlet will increase the MASS at the compressor outlet (that is, a drop in temperature without a drop in pressure). It would be fairly easy to test. Anyone with a WRX + DeltaDash could gather this data from their MAF/MAP sensors. However the theory of why it would happen would be interesting as well. In order for the turbocharger to be "effectively" larger, it would need to flow a greater mass of air at a given PR with the same efficiency, and I cannot get my head around the logic of that.