2014 Ultimate 1 Ton Challenge results

4x4ord wrote:


The drive line can handle tremendous torque and could very likely handle the 3000 or so lbft that comes out the back of the transmission under full fueling. I pull heavy trailers in very soft ground at times and have needed to shift the transfer case into 4 low where the torque is multiplied by 2.72. If the driveline can't handle full fuel in high range just think how severely the fuel must be limited in low range.

Yes they can handle an immense amount, but not full engine torque with resistance and survive in terms of longevity.

Get an OBDII scanner and watch load, you would be shocked at how little load it takes in lower gears to get the job done especially once you are in 4lo.

I'm not the one who put torque management into these trucks, I just know it exists and the reasons for it.

4x4ord wrote:

AH64ID wrote:


The second comment is also about a chassis dyno and how they are effected by engine loading. To make 50 more ft/lbs of torque at 2500 rpms takes 35 more hp, you know the equation since you posted it. So you should have no problems understanding that at 2500 rpms 800 ft/lbs is 380 hp, and 850 ft/lbs is 405 hp... A difference of 35, weird right!. There you go , gears made hp... Um no, not really the point if that was to show the issues of a loading the engine on a chassis dyno, not real world power production. On a chassis dyno taller gearing allows the engine to make more hp, and more torque.. Not because of the gearing but because the load required to spin the tires is higher.

If a vehicle on the dyno is ran in 5th and makes 415/800 and then ran in 6th and makes 425/850 the hp curves are not identical. Which one do you think is more accurate? What do you think made the extra hp in the middle of the rpm band? I can tell you the gearing didn't do it, it just facilitated it.

Think about it from the engine's perspective. An engine is placed on a bench and is running at full throttle and loaded down to 2500 rpm. The power output is measured at the crank and determined to be 500 HP. Now hook it up to a driveline and load it down to 2500 rpm. The engine has no knowledge of what happens down stream of the crank. The power measured at the rear wheels will be less than 500 HP due to inefficiencies in the driveline. If in 5th gear you happen to measure less power than 6th gear it is because more power is being turned into heat while running through 5th or because your dyno is not capable of taking accurate measurements at different wheel speeds or a combination of the two. So you could say gears make heat ... therefore consume power.

Very true real world, but not true on an chassis dyno unless it's a pull down dyno which are rare. If you could find a pull down dyno and run from redline down to 1500 you might see that, and that would be cool info to see.

However, on a standard chassis dyno the engine isn't fully loaded in a shorter gear, the rpms revved too fast for full power to be developed. A chassis dyno measures acceleration of the dyno wheel, if you have a short run with a small mph gain, i.e. short gears, then the power is lower than a run that takes the same time but has more mph gain on the wheel, i.e. taller gear.

This is very common putting a turbo diesel on a chassis dyno, run in the highest gear possible. Increases smoke and low boost are both indicators of the engine not having enough load.




Anyways, this has gone too fat OT. The data here, and elsewhere, gearing increases rearranged wheel torque. The gearing can come from the trans or axle, but in the end the more hp and the more wheel torque means the most work at the highest rate. Taller rear axle gears do fine at speed, 1 gear lower, and lower gears get going quicker.