I was not carefull with my system on my 88 turbo-tbird the clutch started slipping. Car had only 25,000 miles on it and was not abused.
Good luck with your project ShadowWorks.

I think it's brilliant! good luck man let us know how it goes!

Water/mist/vapor/steam
 

I also believe that gains are to be made, but with some different perspectives from my study. Water injection, where a pump pushes liquid through a nozzle and basically atomizes it is used in drag racing and such for power, and I read that it works best with turbo's, ramchargers, or blowers, not so much with naturally aspirated engines.
Therefore:
I am experimenting with vapor injection by vacuum boiling and will report on that later.
I believe the next step is steam, being better atomized and safer than low temperature liquids into a hot engine.
However:
My cohorts have argued that it is the expansion of water in the ICE that produces the effects, not the divergence of water into hydrogen, since the pressure and temperatures are not actually high enough to create this effect.
Therefore:
IF it is expansion, then steam will have less temperature variable to expand and subsequently be less effective than water, however atomized.
Furthermore:
I believe that the use of atomized water mist along with an EFIE will produce verifiable and possibly decent results. The EFIE would overheat the engine at values of around 16:1 (the limit of safety) or more, but the water injection would provide the cooling necessary to allow one to use this device where you otherwise could not. I think a cutout switch would be necessary to allow for accelleration purposes, but the glide mode would be under leanout conditions.
I also would recommend using an EGT to keep an eye on the exhaust temps in case your water unit fails. I figure $50-90 for EFIE(s) and $100 for an EGT, and a few dollars to make an injection unit. Recommendations have been made to limit the EGT to 180 degrees F. max increase over baseline temps.

I think BMW is introducing a system that taps exhaust heat to generate enough power for all accessory loads, supposedly saving 15% in fuel consumption.

regards
gary

I wonder if that's using TEGs or something like the PICC system that never materialized? I've been wondering why TEGs haven't been researched and developed more, since the alternator could almost be eliminated and the free heat waste utilized.
As far as steam input is concerned, the OP was right in that we can do this with little more than a valve and some copper tubing. The trick as I see it would be to find a way to meter and upregulate this as the engine rpm increases. One way would be a mechanical link from the throttle to a metering valve. Another would be a metering pump of some sort with variable current somehow controlled by pulses from the ignition system or tach. I haven't worked that one out yet, but feel free to chime in.

Just build the system like a carb. The only way too have it fail is carelessness. Copper and steel don't mix.