How Does This Work? Voodoo Engineering?

[Cahaba Valley Farm]

Nobody has gone down this road yet but these are 2 completely different frame sized machines. If you compare like for like the l3301 will clobber the lx3310 all day long. Roughly the same ponies but many more differences. I just had trees cut down and the tree guy brought his lx3310 with his wicked 55 for clean up. I had my l3901 and wicked 55 out and he ran both. Horse power aside he flat out told me my machine would out work his all day long.

As Jeff would say that is mostly to do with weight.

 

[Cahaba Valley Farm]

Here is another enigma: 3043D | 3 Series Compact Tractors | John Deere US

With all that power it only has one more ft-lb of torque but a lot more PTO horsepower. I still don't understand how this works.

 

[TMGT]

Higher rated rpm (2800 as opposed to 2500), the torque curve will be on a downward slope at this point so as the engine speed goes up the torque will be going down but the HP will be going up.

I think some of the confusion is that they are listing the HP and torque at the same rpm but because the torque peak is at a lower engine speed its not easy to do a direct comparison.

Looking at 1 or 2 data points doesn't really give you enough info, either post just HP or provide the full curve! Including BSFC

 

[Midniteoyl]

Including BSFC

I wish they would include this, even if its just at PTO RPM.

 

[Cahaba Valley Farm]

Higher rated rpm (2800 as opposed to 2500), the torque curve will be on a downward slope at this point so as the engine speed goes up the torque will be going down but the HP will be going up.

I think some of the confusion is that they are listing the HP and torque at the same rpm but because the torque peak is at a lower engine speed its not easy to do a direct comparison.

Looking at 1 or 2 data points doesn't really give you enough info, either post just HP or provide the full curve! Including BSFC

BSFC?

 

[Midniteoyl]

BSFC?

Brake Specific Fuel Consumption. Basically how efficient the engine is at turning fuel into power.

Brake-specific fuel consumption - Wikipedia

en.wikipedia.org

 

[Midniteoyl]

Some vids to watch. Uses gas engines, but the principles still apply. I wish I could find old Hot Rod articles as there were many that went through these and explained them very well.

 

[rScotty]

I think of power as being how torque is used over time.

Several people have explained it well.
None of them seem to see any Voodoo in the specs.
But they all agree you can't tell anything from a single number. It needs to be looked at over a range.

 

[TMGT]

I think of power as being how torque is used over time.

Several people have explained it well.
None of them seem to see any Voodoo in the specs.
But they all agree you can't tell anything from a single number. It needs to be looked at over a range.

Yup, HP is just work(torque) over time(rpm)

If you know the rpm of the torque peak for both engines you can compare a little bit better, but I think including the tq number at rated rpm is just going to add more confusion when comparing specs.