Dude, I think you need a mathematician or an engineer....
I found this formula for determining temperature from the density and pressure.
http://www.engineeringtoolbox.com/co...ses-d_605.html
And this will tell you the density and volume of a bunch of combustible fuel products.
http://www.engineeringtoolbox.com/fu...mes-d_166.html
Here's one that tells you the temperature of air under various amounts of pressure.
http://www.engineeringtoolbox.com/ai...ity-d_771.html
There's a bunch of other stuff on this page, but this is giving me a headache reading all this math. GACK!
http://www.engineeringtoolbox.com/de...ity-d_290.html
It's got to be out there somewhere! You can find EVERYTHING on the internet if you know the proper terminology for what you're looking for. Unfortunately, I don't speak engineering geek.