Fuel Economy in History

The Predator carb "gulping huge quantities of gas in the process" you got that right! I was getting under 5mpg on a 351c in a light 57 Ford. Carbs can't reat get better. The feedback carbs late in the game would monitor o2 sensors and adjust A/F accordingly. Prett much burning every molecule of fuel in the chamber OR exhaust....but all that does is create heat.Something like 90% of the fuels power is not motion but heat. Turbos reuse a portion of this heat to covert to mechanical energy but the "killer app" would be a thermocouple exhaust of some sort that would take that wasted heat and turn it into electrical energy for a hybrid generator assist but they even produce heat. I think a fuel cell is probably the best MPG in a technical sense.