2018 Dodge 3500 dually gas motor row ratings
With the super high diesel ratings they have, how do the gas motor ones rate?
Forum Discussion
RoyJ wrote:
Normally, I always correct people on the "torque vs HP" argument - as it's hp that pulls you up grades, not torque.
However, this is one exception where the TORQUE of the Cummins allows it for the much higher tow rating. An important spec in tow rating is startability - ability to pull away from a steep grade.
Cummins / Aisin: 930 lb-ft x 3.75 (1st gear ratio) x 4.10 = 14,299 lb-ft rear axle torque. With 33" tire gives 10,400 lbs of tractive effort.
6.4 HEMI / 66RE: 429 lb-ft x 3.23 x 4.10 = 5,681 lb-ft axle torque. With 33" tire gives 4,132 lbs of tractive effort.
The gas engine has only 40% of the starting tractive effort of the Cummins!
This means even with a 15,600 lbs trailer (23,400 GVW), the 6.4 gets beat off the line by a Cummins / Aisin towing 30,320 lbs trailer (39,100 GVW).
Simple math tells us the HEMI can only start out on a 17.7% grade, while the Cummins can pull away from a 26.6% grade!
In real life, the Cummins would perform even better as its torque peak (1700rpm) is much closer to the converter stall than the HEMI (4000rpm).
Nice explanation.
I have ended up starting out on some fairly steep grades towing 33-35k combined with the AISIN/4.10/Cummins combo. Not a single bit if shudder or axle bounce, it simply took off!
