HP question

[MDM]

This something I have been wondering about for quite a while. Is engine HP related to the weight of a tractor? Hypothetically speaking could an engine from a B3030 be put in larger tractor like the L3130 and move the tractor around the same? Could a new B2930 engine be put in a L2800 and still maintain the same power as the original L2800 engine? The difference being about 1,000lbs in the two machines. The 2920 engine is normally moving around a 1500lb tractor where the 2800 engine moves around a 2600lb tractor.

[Crash101]

A certain hp engine in a light weight kubota should perform the same work as a similiar hp engine in a heavier tractor. There will be those who speak of torque rather than hp, but in our tractors, because much of the work is done at high RPM's, it's mostly hp that does that work, and generally speaking 30 hp is 30 hp, no matter which tractor it's placed in.

[Bird]

And then besides the horsepower, you have to consider the gearing; transmission gears, differential gears, wheel and tire sizes. Are they the same or not? Probably not.

[Racer71]

HP is not related to tractor weight but 30 HP is 30 HP.

A heavy tractor consumes more power to move than a light one. This leaves less power to do work.

[rdsaustintx]

None of these are very satisfactory answers (although Bird is always right).

Small Kubotas are wildly, ridiculously, absurdly overpowered tractors. My neighbor has a Ford 555 TLB, my BX will almost fit in his bucket. That machine is a monster, probably 7-8x the weight of a BX. I've seen it do positively amazing things, but the engine is only 65 horses.



Power is velocity x force. Hydraulics can generate HUGE force with little power, just at a lower speed. As for "moving around" that depends on if you are ground-engaging. We really don't use much tractive power for other jobs.

I would *guess* the problem with switching engines would be integration, just making stuff fit, like Bird says (and Bird is always right). I have done it with cars but not a tractor.

[/uninformed rambling]

[rdsaustintx]

Originally Posted by Racer71

A heavy tractor consumes more power to move than a light one. This leaves less power to do work.

Only when you are accelerating or climbing a hill. A heavy tractor just helps get the power to the ground. Ballast certainly does NOT mean less work. Most TLB work is lifting or moving, but not much at the same time.

[john_bud]

Originally Posted by MDM

This something I have been wondering about for quite a while. Is engine HP related to the weight of a tractor? Hypothetically speaking could an engine from a B3030 be put in larger tractor like the L3130 and move the tractor around the same? Could a new B2930 engine be put in a L2800 and still maintain the same power as the original L2800 engine? The difference being about 1,000lbs in the two machines. The 2920 engine is normally moving around a 1500lb tractor where the 2800 engine moves around a 2600lb tractor.

Yes, a little engine can get swapped into a larger tractor. BUT, it won't last as long. (typically - expect the block to break as it is part of the tractor structure and is weaker) And balance won't be there, so you would have issues with certain chores.

The larger engine can also get swapped in (theoretically) and be happy. Balance may be goofy and the front may steer oddly or even wear out faster.


For all of the examples you give, the engines run at about 3500 rpm to generate the rated power. So, the torque question goes away. If you replaced a 45 hp engine that was rated at 3500 rpm with one that was 45 hp rated at 1515 rpm there would be a large torque difference. 68 ft-lb VS 156 ft-lb