rear axle gear ratio
Getting ready to move up to a 3500. I've shopped the available trucks, and have a good idea of what I want. The two I have narrowed down to are a '14 and a '15 Ram 3500. Identical with the exception o...
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I just watched the 2016 Duramax pull 21400 up the Ike.
Doing the same math the Duramax lifted 30,000 lbs the 2225 ft in 9 minutes 48 seconds....so 206 HP. It averaged 49 mpg so that would have taken about 80 HP. So it put out 286 HP and the rated Hp is 397. I never noticed in the video where the Duramax shifts at but I think it revs higher than the Powerstroke and Cummins. It might have averaged 370 crankshaft HP. 286/370 gives it a 77% rating on the Super Ike Dynometer.
Edit:
I screwed up. It would likely take more like 70 rear axle Hp to overcome rolling resistance and drag on the GMC and its trailer at 49 mph. So 276/370 = 75% efficiency. So all three work out very close to the same thing. The Ford should have been forced to shift into 3rd gear at 2400 rpm and it would have made much better use of its power. As for the trucks ability to put their engine's power to the ground goes it looks as though all three are very comparable.
Doing the same math the Duramax lifted 30,000 lbs the 2225 ft in 9 minutes 48 seconds....so 206 HP. It averaged 49 mpg so that would have taken about 80 HP. So it put out 286 HP and the rated Hp is 397. I never noticed in the video where the Duramax shifts at but I think it revs higher than the Powerstroke and Cummins. It might have averaged 370 crankshaft HP. 286/370 gives it a 77% rating on the Super Ike Dynometer.
Edit:
I screwed up. It would likely take more like 70 rear axle Hp to overcome rolling resistance and drag on the GMC and its trailer at 49 mph. So 276/370 = 75% efficiency. So all three work out very close to the same thing. The Ford should have been forced to shift into 3rd gear at 2400 rpm and it would have made much better use of its power. As for the trucks ability to put their engine's power to the ground goes it looks as though all three are very comparable.
