Horsepower is horsepower?

bimbert84 wrote:

wilber1 wrote:

The advantage the 800 has is not peak HP or torque at peak HP RPM. At peak HP, it is producing the same amount of torque as the 650 but because the 800's torque peaks at the same 1600 RPM as the 650, it will be producing more HP at every engine speed until it reaches peak HP RPM which is the same 350 HP at 2900 RPM for both engines.

Exactly right. It's unfortunate the graphs use different scales, or it would be much easier to see. Both the torque curve and the HP curve for the 2011 Cummins are higher throughout the entire powerband, right up to where they meet at 3000 RPM.

Unfortunately, a lot of people will notice the 2011 pulls harder, say "but both have 350 HP," and conclude that HP is therefore irrelevant for pulling. The problem, of course, is that they'll be comparing only peak numbers rather than comparing the curves.

-- Rob

It is too bad they are not in the same scale but it's the shape of the curve that tells the tale. The 800 can make more HP at every RPM other than peak, although the advantage is less the closer it gets to peak. Theoreticaly, the 650 could come closer to matching the 800 but it would need, dare I say it, more gears and would be turning faster in each gear to make the same HP.