The 'sweet spot'....
I've seen several posters indicate that they have found the 'sweet spot' with their engines. How do you know? My thoughts are that the sweet spot is traveling in the highest gear at the lowest s...
Forum Discussion
wolfe10 wrote:
Reality is the "best MPG speed" varies with coach, gearing and terrain.
On flat ground, the lowest RPM you can hold high gear is the best "reasonable" speed. That will be right at peak torque RPM for your diesel.
When I say "reasonable" in most coaches peak torque RPM in 5th gear (MUCH less aerodynamic drag at lower speed) will give better MPG, but is excruciatingly slow!
But, that speed (peak torque RPM, 6th gear) in rolling hills will cause a downshift on each hill-- so a little higher speed that will allow you to stay in high gear is better.
I agree. 1450 is max torque on my ISC. 67mph is 1750 in 6th. A down shift leaves the RPM at 2050 right at peak HP.
