content: Could diesel help that?  Part of the problem with Wankel engines is that the combustion gases come into contact with a huge surface area inside of the engine, which acts like a big heat sink, removing heat from the gasses and reducing engine efficiency. You want the heat of combustion contributing to the expansion of the combustion gasses and creating pressure which can be used to create mechanical energy, not being sucked up by the cooling system and dissipated by the radiator.