haha that shit sounds wack!
engine power is proportional to density, fuel, pressure, rpm, etc
Im thinking you would probably need to come up with a formula for a given curve on a compressor map which fits the turbo (based on the amount of boost you choosing to run);
http://en.wikipedia.org/wiki/Compressor_map
http://www.turbocharged.com/catalog/compmaps/fig9.html
Then work out roughly how much a psi of boost would increase in horsepower or something. Never covered engine design etc in my stream of engineering.
My friends are in their final year of aerospace engineering and have crunched some epic numbers for jet engines etc, ill run the question past them and see if they got any ideas.