why horsepower

[1930]

Tractors are marketed by HP because it's an easy number. Most people look for PTO HP, for work done with a PTO driven implement, and weight, for work done with ground engaging equipment. My previous L3301 and current L3560 are vastly different tractors in the ground engaging category, but in theory any PTO implement the L3560 runs the L3301 would handle fine. Manufacturers use engine HP because it's a higher number, and I'm sure some of them like that they can hide "clunkers" with low efficiency between the engine and PTO HP ratings.

That said, the L2501 isn't a slug. It's probably the best balance of HP to weight offered in the standard L. I could, and have on more than one occasion, spun 3 tires with the L3301. It simply doesn't have enough iron, even loaded down with beet juice and a FEL for the tires to grab and pull properly when powered by the higher HP version of the engine. I can only imagine the L3901 is worse.

The L2501's main deficiency is in PTO HP. With only 19 PTO HP on tap you're in a situation of having a 5' wide tractor that really should be paired with 4' PTO implements.

The other issue with the tractor is they de-rated the hydraulic pump. I've never been clear on why. But that leads to reduced flow for any implements and longer cycle times for the loader and backhoe, as well as a negligible drop in pressure, which manifests as slightly reduced capacity on the loader and backhoe.

As far as "turning up" a modern tractor, it's not like the old days. The L2501 uses the same direct injection engine as its bigger brothers. Everything's controlled by the brainbox, and I don't think there's a large enough market to support chipping it.

I have only read your response thus far, I'm at the shop, have to start working and will read the others later.

I found your response informative and easy to understand, I'm short on time right now, I'll make a better response later on this evening but I'd like to mention that I thought the l2501 was not computer managed therefore wouldn't need a chip to enhance performance. Thanks

 

[oosik]

For me it's all about weight. I could gear my previous tractor down and spin all four wheels - same with my new M6040. However, the added weight of my M6040 ( 10,100# ) means extra "grunt" before the four wheels start spinning.

Bigger tractor, more weight, more grunt, larger implements = larger projects.

 

[1930]

Tractors are marketed by HP because it's an easy number. Most people look for PTO HP, for work done with a PTO driven implement, and weight, for work done with ground engaging equipment. My previous L3301 and current L3560 are vastly different tractors in the ground engaging category, but in theory any PTO implement the L3560 runs the L3301 would handle fine. Manufacturers use engine HP because it's a higher number, and I'm sure some of them like that they can hide "clunkers" with low efficiency between the engine and PTO HP ratings.

That said, the L2501 isn't a slug. It's probably the best balance of HP to weight offered in the standard L. I could, and have on more than one occasion, spun 3 tires with the L3301. It simply doesn't have enough iron, even loaded down with beet juice and a FEL for the tires to grab and pull properly when powered by the higher HP version of the engine. I can only imagine the L3901 is worse.

The L2501's main deficiency is in PTO HP. With only 19 PTO HP on tap you're in a situation of having a 5' wide tractor that really should be paired with 4' PTO implements.

The other issue with the tractor is they de-rated the hydraulic pump. I've never been clear on why. But that leads to reduced flow for any implements and longer cycle times for the loader and backhoe, as well as a negligible drop in pressure, which manifests as slightly reduced capacity on the loader and backhoe.

As far as "turning up" a modern tractor, it's not like the old days. The L2501 uses the same direct injection engine as its bigger brothers. Everything's controlled by the brainbox, and I don't think there's a large enough market to support chipping it.

Bearing in mind I know almost nothing about PTO engineering ( as far as I know at this point it's nothing more than another output shaft on the trans. ) couldn't the user change gears within the 2501 to change the speed of the output shaft to their desires (assuming the gears we're avail. ) and if so why wouldn't Kubota have made it more efficient in the first place?


On the pump ( and again know even less about the pump) couldn't the user replace the pump with a more efficient unit or wordy case bore/sleeve their existing pump and match with a larger piston to increase volume?

I already commented on the brainbox above.

I'd like to hear whatever you can tell me about the things we have discussed above. Thanks

 

[1930]

For me it's all about weight. I could gear my previous tractor down and spin all four wheels - same with my new M6040. However, the added weight of my M6040 ( 10,100# ) means extra "grunt" before the four wheels start spinning.

Bigger tractor, more weight, more grunt, larger implements = larger projects.

I have some pict. thoughts to share with you once I get home to my desktop.

 

[1930]

Thanks for the other comments, food for the brain

 

[Zebrafive]

Bearing in mind I know almost nothing about PTO engineering ( as far as I know at this point it's nothing more than another output shaft on the trans. ) couldn't the user change gears within the 2501 to change the speed of the output shaft to their desires (assuming the gears we're avail. ) and if so why wouldn't Kubota have made it more efficient in the first place?


On the pump ( and again know even less about the pump) couldn't the user replace the pump with a more efficient unit or wordy case bore/sleeve their existing pump and match with a larger piston to increase volume?

I already commented on the brainbox above.

I'd like to hear whatever you can tell me about the things we have discussed above. Thanks

PTO rpm is standardized at 540rpm or 1000rpm. Implements are designed with this in mind. Manufactures can design what engine rpm is required to produce the correct PTO rpm. It's normally at peak engine HP.

 

[Egon]

Anyone recall drawbar horsepower?? It was delegated to the pulling capabilities.

 

[TheMadOne]

Bearing in mind I know almost nothing about PTO engineering ( as far as I know at this point it's nothing more than another output shaft on the trans. ) couldn't the user change gears within the 2501 to change the speed of the output shaft to their desires (assuming the gears we're avail. ) and if so why wouldn't Kubota have made it more efficient in the first place?


On the pump ( and again know even less about the pump) couldn't the user replace the pump with a more efficient unit or wordy case bore/sleeve their existing pump and match with a larger piston to increase volume?

I already commented on the brainbox above.

I'd like to hear whatever you can tell me about the things we have discussed above. Thanks

The PTO goes 540 RPM. That's it. That's all you get. That's what implements are designed to handle. You can over/under speed it, but the designed setup is what everything should be sized by. (Torque X RPM)/5252=HP. If we know RPM is 540 then it's a simple enough calculation to get HP based on how much actual force the engine turns the shaft with, PTO HP is calculated at the peak of the Torque curve of the engine. As speed is constant then there is no "changing gears". The exception to this is 540E PTO mode that some tractors have. This actually reduces available PTO HP by moving the point that the drive system provides 540RPM off the peak of the torque curve.

As for the pump, it's buried inside the tractor, and not user serviceable. It also controls the steering and the brakes. Unless you really know your stuff, any "upgrades" you make are a good way to void your warranty and end up with an expensive lawn ornament.

 

[1930]

The PTO goes 540 RPM. That's it. That's all you get. That's what implements are designed to handle. You can over/under speed it, but the designed setup is what everything should be sized by. (Torque X RPM)/5252=HP. If we know RPM is 540 then it's a simple enough calculation to get HP based on how much actual force the engine turns the shaft with, PTO HP is calculated at the peak of the Torque curve of the engine. As speed is constant then there is no "changing gears". The exception to this is 540E PTO mode that some tractors have. This actually reduces available PTO HP by moving the point that the drive system provides 540RPM off the peak of the torque curve.

As for the pump, it's buried inside the tractor, and not user serviceable. It also controls the steering and the brakes. Unless you really know your stuff, any "upgrades" you make are a good way to void your warranty and end up with an expensive lawn ornament.

Great answer and more to think about once my warranty vexpires and assuming I see a problem.

All I see is improve torque curve

 

[MossRoad]

Anyone recall drawbar horsepower?? It was delegated to the pulling capabilities.

Yes. The topic is rarely discussed here.