kubota vs. kioti

[tomato coupe]

Neither- my point is a larger displacement engine that has a lower rated power rpm will produce more torque and therefore more horsepower at rpms under the rated rpm compared with an engine that has comparable horsepower at its rated operating rpm. Although the lower rpm engine should accelerate faster thru its rev range because it is producing more torque and therefore hp under the curve.

I f you compare the two graphs you will see that even though the 2000 rpm engine is actually only producing about 48 hp at rated speed compared to the Kubota which produces 50 hp at rated speed, at all operating speeds the 2000 rpm engine is producing much more torque and therefore much more horsepower at any rpm point in its operating range.

Which also means it can do more work on average than the higher revving engine -unless the Kubota is only compared while operating near or at wide open speed.

In a geared tractor configuration the engine is in many applications not running at rated speed but will have more horsepower available especially at low engine speeds - which is an advantage when pulling heavy implements from a dead stop. And many implements in real world conditions.


As i have said before i don't believe the 2000 rpm engine has an advantage in a Hydrastatic drive tractor -where the tractor is operated at peak rpm for the hydros benefit. i do believe it is an advantage in a geared tractor operating many times at lower rpms... i took a few a test rpm horsepower points on the 2000 rpm engine these are ballpark #s but at 1000rpm the 95a engine is @ 30hp the kubota isn't even on the chart but looks to be around 13 hp
@ 1500 rpm 95a @41hp kubota @34 hp
@ 1800 rpm 95a @44hp- Kubota @40 hp

I think due to epa regs and possibly manufacturing costs in materials manufacturers have cranked up the rpms on these diesels to achieve comparable hp #s using smaller and smaller displacement engines- but sacrificed some abilities the lower revving higher torque engines had in the past...

One more thing i am not intending to pick on Kubota it was just the chart already posted.
This seems to be industry wide and if the trend away from geared machines continues maybe it won't even matter because most hydro machines are operated at near rated rpms anyway... JMO and:2cents:

If you want to compare the horsepower of these two engines, you should do it as a fraction of the maximum operating RPM.

Doing so, you get the following:

Kubota Engine
2700 RPM (100%) 50 HP (100%)
2430 RPM (90%) 47 HP (94%)
2160 RPM (80%) 44 HP (88%)
1890 RPM (70%) 39 HP (78%)
1620 RPM (60%) 35 HP (70%)
1350 RPM (50%) 28 HP (56%)

95a Engine
2000 RPM (100%) 48 HP (100%)
1800 RPM (90%) 45 HP (94%)
1600 RPM (80%) 42 HP (88%)
1400 RPM (70%) 39 HP (81%)
1200 RPM (60%) 34 HP (71%)
1000 RPM (50%) 29 HP (60%)

where the numbers in parentheses are the percentage of the values at maximum operating RPM.

When compared this way, the 95a engine still has a horsepower advantage over the Kubota at lower RPMs, but it is very slight. The largest advantage (60% - 56% = 4%) occurs when the engines are run at 50% of their maximum RPMs.

Cheers

 

[tomato coupe]

I love engine performance charts -- there is so much more information in them than just the maximum horsepower and maximum torque that you get in tractor brochures. I was looking at the charts of the two engines previously discussed and noticed something interesting. The specific fuel consumption of the two engines is almost exactly the same at maximum RPM, but the "high torque" engine loses efficiency when operated in the region of maximum torque.

Here are the numbers:

1) What is the specific fuel consumption of the 95A engine when operated near maximum torque (about 1250 RPM)?

=> From the chart, the engine burns about 232 g/kW-h (grams per kilowatt-hour). Surprisingly, this is about the same as the specific fuel consumption ( 233 g/kW-h) at maximum RPM.

2) What is the specific fuel consumption of the Kubota engine when operating at an RPM to match the horsepower of the 95A engine?

=> At 1250 RPM the 95A engine produces about 35 HP (26 kW). The Kubota will produce the same power at about 1650 RPM, and it will have a specific fuel consumption of 213 g/kW-h. This is about 90% of the specific fuel consumption (235 g/kW-h) of the engine at maximum RPM.


So, the two engines have the same efficiency when running at full power, but the Kubota engine is about 10% more efficient when running at 70% power capacity.

===> Before anyone starts screaming, I not trying to make an argument that "high torque" engines are, in general, less efficient than other engines. I'm only comparing these two engines.

 

[tomato coupe]

Its that slight upward bulge in the torque curve. It would be nice to have a good bump reasonably close to max power. RPM could then fall a little ways at constant power. Kinda hard to arrange in a passive fashion.

I would argue the opposite. Imagine an engine whose power doesn't drop at all as RPMs drop, i.e. the engine has a flat power curve. The torque curve of this engine would monotonically increase as RPMs decrease and, therefore, the torque maximum would occur at the bottom of the useable RPM range.

Looking at it another way... Maximum torque occurs at an RPM where the rate of decrease of horsepower (as RPMs drop) accelerates. You would like this rapid loss of horsepower to occur at a very low RPM, therefore you want the torque peak to occur at a very low RPM.

Cheers

 

[SHAC]

Hi. I purchased a Kioti DK35HST new in 2008 along with a hoe, loader, tiller, blower, rotary spreader, rough cut mower, etc. I had rented many Kubota tractors over the years and had set out to purchase Kubota. When I did the comparisons with Kioti, Kubota, John Deer, and Massey Fergusson (all in the same size rane) it turned out that Kioti out shawn them all. I now have nearly 1000 hours on my Kioti. I had a couple of minor hydraulic issues with it when it was new. It has been an excellent hard working piece of equipment ever since. My biggest complaint is that my Kioti is a very noisy running motor. Steven, Hawkestone, Ontario

 

[SPYDERLK]

1. I agree.

2. I have no problem when someone describes an engine as "having a good amount of torque rise." It immediately tells me that the engine doesn't lose horsepower (as the RPMs drop) as quickly as an engine that doesn't have the same torque rise.

3. I think one reason the "horsepower" vs. "torque" debate is so lively is that some people treat torque as something distinct and magical. It's not. If you know the torque of an engine at a given RPM, then you know the horsepower at the same RPM. Torque (at a given RPM) is no more or less important than horsepower (at the same RPM). Arguing that torque is most important is silly. Your second sentence can be be written (with equal validity) as:

"Lose a little ground speed and "torque" on thru w/o a shift." or

"Lose a little ground speed and "horsepower" on thru w/o a shift.

4. Perhaps you mean "tractor-a-bility" rather than tractability. In mathematics and physics a problem is said to be tractable if it can be solved without the use of extraordinary measures.

Yes.

Tractable has its root in dragging or hauling.- ease of [physical] management or control. Adoption to describe management of math is a reasonable extension, but not primary.

I would argue the opposite. Imagine an engine whose power doesn't drop at all as RPMs drop, i.e. the engine has a flat power curve. The torque curve of this engine would monotonically increase as RPMs decrease and, therefore, the torque maximum would occur at the bottom of the useable RPM range.

Looking at it another way... Maximum torque occurs at an RPM where the rate of decrease of horsepower (as RPMs drop) accelerates. You would like this rapid loss of horsepower to occur at a very low RPM, therefore you want the torque peak to occur at a very low RPM.

Cheers

So nice. No transmission needed. A diesel electic train does pretty close.

>>I was of course talking about about a system with a little less overhead that could hold HP for a few hundred rpm. Since HP requirement drops with speed the right single gear for task could provide a very tractable prime mover. -- The Britten racing motorcycle had an engine that was more like the composite train power source. ... It put out ~ 155Hp from 8-13Krpm. Hi compression and very sophisticated fueling and timing controls enabled it.
larry

 

[hurliman]

As a Kioti dealer I will assure you Kioti is the superior machine..LoL
Any American market tractor you buy no matter what color has a better than average chance of being a quality machine that will give years of good service.
Just get the brochures and price from both and start comparing apples to apples.
Next compare dealers and customer service after the sell.
Third I would call and compare prices and availability to parts like filters and water pumps.
JMO,
Donald

As a former {retired} Kubota and Kioti dealer, yes Kubota did everything they could do to stop selling Kioti's, they finally took the Kubota contract away from me. I was pissed for a long time, and finally realized that they did me a favor. Kioti is hands down better than Kubota. Kubota uses psychology and advertising to get people to buy their product. It cut my shop work down by at least 80%, which I wanted. Sell a Kioti and it rarely comes back for any problem. I think, as a rule, any Korean tractor is built heavier and better than a Kubota. In 34 years selling tractors, you learn a thing or two!

 

[sawtooth]

As a former {retired} Kubota and Kioti dealer, yes Kubota did everything they could do to stop selling Kioti's, they finally took the Kubota contract away from me. I was pissed for a long time, and finally realized that they did me a favor. Kioti is hands down better than Kubota. Kubota uses psychology and advertising to get people to buy their product. It cut my shop work down by at least 80%, which I wanted. Sell a Kioti and it rarely comes back for any problem. I think, as a rule, any Korean tractor is built heavier and better than a Kubota. In 34 years selling tractors, you learn a thing or two!

I have never owned one but spec wise Mahindra too looks to be a heavy well built machine.

 

[paulfun9]

As a former {retired} Kubota and Kioti dealer, yes Kubota did everything they could do to stop selling Kioti's, they finally took the Kubota contract away from me. I was pissed for a long time, and finally realized that they did me a favor. Kioti is hands down better than Kubota. Kubota uses psychology and advertising to get people to buy their product. It cut my shop work down by at least 80%, which I wanted. Sell a Kioti and it rarely comes back for any problem. I think, as a rule, any Korean tractor is built heavier and better than a Kubota. In 34 years selling tractors, you learn a thing or two!

This makes me feel much better about my recent purchase of a Kioti over the Kabota.

 

[paulfun9]

As a former {retired} Kubota and Kioti dealer, yes Kubota did everything they could do to stop selling Kioti's, they finally took the Kubota contract away from me. I was pissed for a long time, and finally realized that they did me a favor. Kioti is hands down better than Kubota. Kubota uses psychology and advertising to get people to buy their product. It cut my shop work down by at least 80%, which I wanted. Sell a Kioti and it rarely comes back for any problem. I think, as a rule, any Korean tractor is built heavier and better than a Kubota. In 34 years selling tractors, you learn a thing or two!

This makes me feel much better about my recent purchase of a Kioti over the Kabota.

 

[TomSeller]

As a former {retired} Kubota and Kioti dealer, yes Kubota did everything they could do to stop selling Kioti's, they finally took the Kubota contract away from me. I was pissed for a long time, and finally realized that they did me a favor. Kioti is hands down better than Kubota. Kubota uses psychology and advertising to get people to buy their product. It cut my shop work down by at least 80%, which I wanted. Sell a Kioti and it rarely comes back for any problem. I think, as a rule, any Korean tractor is built heavier and better than a Kubota. In 34 years selling tractors, you learn a thing or two!

Opinions are like noses.