Hey 1M, if your TIO 540 is running properly, it's probably using 165 per hour. Our's do........... (350 H.P.) NZMarty, you ever seen a Queenair? Geared AND supercharged!!! Pains in the arse to manage properly tho...... and that T.B.O...... ouch!!!!!! Inverted, you kind of missing the point of Turbo/Supercharging. Usually used to boost Take off H.P., and increase cruise manifold pressure, giving altitude and cruise speed increases. Because the a/c engine is usually operated at constant power, supercharging in both forms quite useful in some circumstances. It's a different animal to the car type Turbo or Supercharging