whats the return, or formula for how much psi(pounds per square inch) is made when fuel is burned in an engine( like a standard v-6)?

need specs about the engine and how much fuel is in the cylinder how much of it actuall burns. for the engine we need the volume of the cylinder when its at its smallest and we also need the temperature post combustion if you give us the precombustion temperature we can work out the post combustion temperature. we also need the pressure of the moment of combustion. we need more info basically

i guess what i was asking for was a formula that would tel me how to get what i'm asking for.