What now...fuel conservation mode in auto racing? Can't wait for the Prius to take the lead in the last lap... 
A Formula One engine is not fuel efficient. I'm guessing they average around 2-3 mpg. It's not a case of fuel conservation. It's a case of having to carry ~350 lbs. of fuel on board and setting up the car to handle well throughout the course of the race. Having an engine that burns less fuel is an advantage, but that advantage cannot make up for a poor handling car or a car that wears out the tires five laps into the race.
