Ford V10 revisions

Bruce Brown wrote:
Exactly.

Take a low torque Cummins ISB @ 300HP/600TQ and the same MH with a Cummins ISC @ 300HP/950TQ and go climb the Rockies. It will be very apparent what number means the most.

Now take a 20 HP farm tractor from the 50s and compare it to today's 25HP lawn mowers and see which one gets the job done.

And lastly, you cannot figure HP without torque - HP = RPMxTorque/5252. Torque is a constant, HP is just a calculation.

For my money, I'll looking for torque first, HP second.

If the two 300 HP engines are operating at their maximum power point of 300HP, they'll climb the rockies equally as well. The RPMs may well be different, of course.

Tractors are trickier because they have different jobs (I would not find it at all convenient to mow my yard with a 1950's tractor, nor would I pull a hay wagon with a lawn tractor that lacks the weight and braking power to safely control it) and are sometimes talking of different ratings (drawbar power vs. engine output power).

If you really do want only torque for your motorhome engine, all you need to do is put a gear reduction between your engine and your transmission and you can have all the torque you want, as your formula demonstrates. You could then adjust your axle final ratio to compensate if you wanted. It wouldn't help the real world performance of your vehicle one bit, but you'd have gobs and gobs of torque on the spec sheet.

Power is usually calculated from torque and RPM more because it's hard to measure directly, not because it's a less fundamental concept. Power is the rate of energy production or equivalently the speed at which work is done. Torque is merely rotary force; you can have torque with zero work and zero power. I've seen this myself when trying to remove stuck bolts and nuts; I apply as much torque as I can, but nothing moves.