Why do you Cummins guys want more gears

Groover wrote:

mkirsch wrote:

SweetLou wrote:
Not needed. More speed towing is dangerous for many reasons, and you achieve a good speed now. Lugging any engine while pulling a weight not good either. Continual searching for correct gears can't be good. The best overall range for towing with that Cummins is around 1800 RPM so in my opinion not needed.

Most of what you said is an argument FOR more gears.

Lugging is certainly not good for the engine. You need more gears to keep the engine in the ideal RPM range over varying conditions.

This raises the question of what is the definition of lugging and engine? Every vehicle that I own keeps the engine turning as slow as it can while providing the required power, presumably for fuel economy. I frequently force a downshift but I also wonder what the thought process was for the engineers that are designing those drivetrains and what they consider lugging to be.

Lugging is when you are in too high of gear at a low rpm(generally below peak torque) with your foot past 75% throttle and the truck is not accelerating or barely accelerating. You will generally see your EGT's spike when lugging. This cannot be done in an automatic because it would shift way before it gets to this point. It can only be done in a manual trans unless the auto trans is specifically tuned to do so.

I have a tune that will allow my engine all the way down to 950 rpm and even then it is not lugging since it has enough torque that low to easily accelerate under light throttle when unloaded even up slight hills. Of course, I get my best fuel mileage on this tune since it keeps the RPMs low when not towing, however, it is not an ideal tune for towing.