I guess the First law of thermodynmics does not apply to turbos. I always thought heat/energy sent out the exhaust was wasted and deducted from the total efficency of the engine. I also thought using that wasted exhaust heat and energy to spin a turbo was beneficial to improving cylinder filling. I also thought it if it took x amount of gallons of fuel to move a car y amount of miles and z amount of heat went out the exhaust, by lowering z I could go Y+ miles or use x less gallons.
