Tractor classification — HP vs torque

[LD1]

This here illustrates how higher HP will get the job done faster but torque will get more work done…

Thats not an illustration of torque. Its weight/traction......and dont even look like they had weight on the sled.

 

[Chewwy]

Interesting video but it does nothing to prove the claim that “torque gets more work done.”

 

[S854]

I still don’t get it… I once had a (roughly) 110 HP BMW 2002tii… the car was quick, handled well and was an absolute ball to drive…

However, that cars engine didn’t have any hope to be able to move that CASE an inch… let alone the sled (weighted or not)

 

[Chewwy]

I still don’t get it… I once had a (roughly) 110 HP BMW 2002tii… the car was quick, handled well and was an absolute ball to drive…

However, that cars engine didn’t have any hope to be able to move that CASE an inch… let alone the sled (weighted or not)

Sorry you don’t get it.

Properly geared the 110 hp engine could move the Case just fine, but likely not very fast. Torque can be mutipled via gearing. HP cannot be multiplied by gear ratios.

 

[S854]

I’m just gonna wash out my brain, forget this whole “HP vs torque” thing and enjoy my tractor…

Probably better this way…

 

[etpm]

I wonder just how true HP figures are. I have a JD riding mower with a 24 HP Kohler engine. I have a Yanmar YM23210 tractor with either a 23 HP engine or a 27 HP engine. I'm not sure which because I have seen specs both ways. But even if it has a 27 HP engine my tractor will way out perform the JD pulling something at the same speed. Better than twice as good and 3 HP wouldn't account for the difference. And my tractor weighs a whole lot more than the riding mower. I believe the HP spec for my tractor but not the one for the JD.
Eric

 

[Chewwy]

I wonder just how true HP figures are. I have a JD riding mower with a 24 HP Kohler engine. I have a Yanmar YM23210 tractor with either a 23 HP engine or a 27 HP engine. I'm not sure which because I have seen specs both ways. But even if it has a 27 HP engine my tractor will way out perform the JD pulling something at the same speed. Better than twice as good and 3 HP wouldn't account for the difference. And my tractor weighs a whole lot more than the riding mower. I believe the HP spec for my tractor but not the one for the JD.
Eric

I assume your JD Riding mower is gas powered and your Yanmar tractor is diesel powered. Their operating characteristics are significantly different.

Look at the typical torque/hp vs speed curve for both gas and diesel engines. Diesel engines typically develop peak torque at low rpm that is well below the rpm for peak hp. Gas engines typically develop both peak torque and hp at significantly higher rpms.

 

[WinterDeere]

I still don’t get it… I once had a (roughly) 110 HP BMW 2002tii… the car was quick, handled well and was an absolute ball to drive…

However, that cars engine didn’t have any hope to be able to move that CASE an inch… let alone the sled (weighted or not)

What is the BMW's ground speed at 2500 RPM in its lowest gear? Now compare that to your tractor at 2500 RPM in its lowest gear.

Does that clear it up?

I wonder just how true HP figures are. I have a JD riding mower with a 24 HP Kohler engine. I have a Yanmar YM23210 tractor with either a 23 HP engine or a 27 HP engine. I'm not sure which because I have seen specs both ways. But even if it has a 27 HP engine my tractor will way out perform the JD pulling something at the same speed.

As already noted, different power curves, which results in different torque at each RPM. Also, there are multiple methods by which horsepower can be measured, all valid, but with different caveats and results.

 

[etpm]

I assume your JD Riding mower is gas powered and your Yanmar tractor is diesel powered. Their operating characteristics are significantly different.

Look at the typical torque/hp vs speed curve for both gas and diesel engines. Diesel engines typically develop peak torque at low rpm that is well below the rpm for peak hp. Gas engines typically develop both peak torque and hp at significantly higher rpms.

Yeah, I understand the torque differences. It doesn't matter where the rpm is. The JD doesn't come close in pulling power. I set the JD throttle high and use the HST pedal for low speed. This should give me the best pulling power. Yet the engine lugs down way before the engine in the Yanmar. The JD just cannot pull near the load without the engine lugging way down that the Yanmar can. I think either Kohler is overstating HP figures or Yanmar is wildly understating the HP output of their engines. I don't have a dyno and so can't test the engines that way. So I really don't know how much HP I am getting at the rear wheels.
Eric

 

[Chewwy]

Yeah, I understand the torque differences. It doesn't matter where the rpm is. The JD doesn't come close in pulling power. I set the JD throttle high and use the HST pedal for low speed. This should give me the best pulling power. Yet the engine lugs down way before the engine in the Yanmar. The JD just cannot pull near the load without the engine lugging way down that the Yanmar can. I think either Kohler is overstating HP figures or Yanmar is wildly understating the HP output of their engines. I don't have a dyno and so can't test the engines that way. So I really don't know how much HP I am getting at the rear wheels.
Eric

Thats the difference between the performance of diesels and gas engines. Diesels when loaded drop in rpm but the available torque increases with that drop in rpm. Gas engines just drop in rpm and also drop the available torque.