Quote: Interesting thread. I have a question about the optimal cruise rpm. What is the reasoning behind the peak torque rpm being the optimal cruise rpm? Peak torque rpm is determined at full throttle. Cruise is done at fairly light throttle. Why would peak torque rpm be the optimal cruise MPG rpm - theory-wise? -Shupe
Peak torque occurs at the lowest brake specific fuel consumption, which is how much fuel you use per HP per hour. The engine makes the most torque at its most efficient RPM. Go above this RPM, and the engine will make more HP, but less torque, and it will be using more fuel to do it with less HP per unit of fuel.
