[Stan]

On a tangentially related note, In 1963 Rover entered a turbine powered car in the 24 Hours of Le Mans race, and averaged 6 mpg. A year later they averaged 13 mpg with essentially the same engine, only using the exhaust air to preheat the intake air. With hot intake air the engine was down several horsepower, but since it was able to go twice as many laps between refills, its overall performance didn't suffer much.

I have often wondered if preheating/reheating the fuel and intake air might result in FE gains with diesel engines.

Rover's 1964 turbine car entry at Le Mans...