[Ducati] themodynamics

[mark middleton]

A good way to look at thermal efficiency is to see the engine as a box, we 
put in calories as fuel, (something like 17000btus per pound perfectly 
combusted) and out comes two things, horse power (work done) and heat 
rejected to atmosphere. Anything we do to reduce heat rejection to 
atmosphere automatically (all other things being equal) becomes work done. 
Turbos extract energy (sensible temperature) from the exhaust, therefore 
reducing heat rejection. Simply adding more BTUs (the propane question) does 
nothing unless there's oxygen left to be burned. Remember one oxygen 
molecule to one  hydrocarbon makes carbon monoxide and about 12000 BTUs per 
pound, two oxygens per hydrocarbon makes carbon dioxide and 17000 BTUs. More 
air is a good thing, except air is only 21 percent oxygen, all that nitrogen 
  goes through carrying heat off to the atmosphere, not a good thing. The 
answer is enough to leave a measurable trace in the stack (O2 sensors) not 
too much. As you guys well know, make up for under cooled cylinder heads 
with rich mixtures and all bets are off. Perfect mixtures may not work in 
imperfect engines!
Propane has an octane rating of something like 120, and comes perfectly 
atomized, if it helps a lot I think it proves you have other shortcomings.

   from just another Kevin Cameron wanna-be