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...
Forum Discussion
Cummins12V98 wrote:
4x4ord
My 11 HO Dually dynode 304 out of 350 that's 87 percent. The newer RAM's are at that percent of higher. The Ford's are less than 80 as you noted.
Let's compare the results of the Ike dyno run
The Ram lifted 38600 lbs 2225 ft in 12 minutes 28 seconds. That required 2225 x 38600/748/550 or 209 HP. (1 hp is the power required to lift 550 lbs 1 ft in 1 second)
Additionally the Cummins provided power to overcome rolling resistace and drag. It pulled the 8 mile hill at an average speed of 38.5 mph. This would have required approx 62 Hp. If the Hp of the Cummins is 352 @ 2100 and 385 at 2800 then a the engine would have averaged somewhere close to 369 HP throughout the run. So 271/369 gives the Ram a 73% efficiency rating on the Super Ike dyno.
So now the Ford:
38600 x 2225/683 seconds / 550 ft lbs/sec = 229 HP. Additionally the Powerstroke provided the power to run the race at an average speed of 42 mph....about 69 Hp. The Ford ran between 2100 and 2800 rpm where it produces between 366 and 440 HP. So the average crankshaft output of the Powestroke should have been somewhere close to 403 HP. And (229+69)/403=74%.
