Quote: 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.
That's not necessarily wrong, but, again, fails to account for the fact that while traveling at low-load highway speeds, a turbocharged IC gas engine is still making vacuum and not seeing any boost or associated benefits. So, the heat passing through the turbo and out the exhaust is still "wasted".
Pretty sure that was covered on the first page though.
This point would apply more to an industrial or constant load application where you are always making boost.
