I actually was talking about thermal efficiency of two-stroke vs. 4-stroke, and believed that overall four-stroke does better. Reading about just a little bit,

I actually was talking about thermal efficiency of two-stroke vs. 4-stroke, and believed that overall four-stroke does better. Reading about just a little bit, this may not be the case... depending on what application you are talking about. I would expect to be some differences between a 10-ton marine two-stroke on a ship vs. a 49cc two-stroke on a moped in terms of efficiency.