Does engine HP affect driving power

[Bentrim]

I have not read all the replies and may be repeating what has already been discussed. Any transfer of power uses power that is why there is less power at the PTO and the wheels than the engine can produce. That said some means of power transfer are more efficient than others. Anyone that has taken the Kohler certification test should be aware of this. Note that a gear type transmission transfers more power than a hydro. Simply put a gear transmission is efficient due to low friction losses. A hydro uses a variable displacement pump to drive a fixed displacement motor. As with all hydraulic systems the hydro has a relief valve that limits the pressure of the system to prevent broken hydraulic components. A gear transmission is limited by the strength of the components of it, hopefully the engineer did his job correctly and either the clutch or traction is the weak spot. Most hydros are used with a gears transmission ranges so the tractor can be used efficiently. Operating a hydro overloaded can overheat it and cause seal and component failure, Remember more horsepower and or torque output of an engine the more fuel he tractor will use. Although many people desire high power tractors a smaller tractor used at a slower speed and smaller equipment can do the work as a bigger unit could just at a slower speed. As any racer knows speed costs money. On the other hand hydros have the ease of use compared to a gear, you don't need to figure what gear to select and possibly change, a hydro allows the change speed by moving a pedal or lever. Back in the day garden tractors with hydros always had a bigger engine than one with a gear transmission. Sometimes the choice is determined by the ease of use. Just remember ease of use of a hydro can be higher priced more fuel used, and more power required than the simplicity of of a gear transmission. the choice is up to the buyer. and /or user.

 

[Tony H]

My father in law let's me use his 25hp HST tractor quite often. Some of it's use is maintaining the road we live on. It really struggles going up any kind of hill especially with a load of gravel. I know the engine hp doesn't affect lift capacity because it's really based on what the hydraulic pump can do. But what about a HST transmission. Really not that familiar with how those work. Are they hydraulically driven. Basically I'm asking about it I buy a tractor and get a 40hp or so engine will that alleviate the issue of not being able to pull hills very well

Most hat tr

 

[Tony H]

Most HST tractors have High, Medium and Low gears. If you are in the higher gears, yeah, it'll struggle. Ate you aware of the gear options?

 

[Max Power]

I think what the OP wants to know is whether he needs a bigger tractor with more than 25 horsepower. Bigger is not always better, there are trade-offs. The problem, I believe, is not lack of horsepower, but lack of drive efficiency to use that horsepower. In a geared tractor, 25 hp is more than enough to climb just about any grade with as much weight as the tractor's properly fitted loader was designed to carry. I own a manual trans, 25 hp, Kubota B2150. I can fill the bucket with sand and climb any grade upon which the wheels can get traction. It's not always fast, but it never fails. The HST B2150 can't pull the same grades, and even pulling lesser grades repeatedly will soon result in overheated transmission fluid.

I'm not sure the OP knows how to frame the question let alone understand power vs what one asks from a tractor. too many people think there is some magic out there. like all things in life there are compromises.

 

[Martin Roper]

My father in law let's me use his 25hp HST tractor quite often. Some of it's use is maintaining the road we live on. It really struggles going up any kind of hill especially with a load of gravel. I know the engine hp doesn't affect lift capacity because it's really based on what the hydraulic pump can do. But what about a HST transmission. Really not that familiar with how those work. Are they hydraulically driven. Basically I'm asking about it I buy a tractor and get a 40hp or so engine will that alleviate the issue of not being able to pull hills very well

More power should allow you to do the same work easier and be kinder to the kit, but if you use the extra power to do extra work it will still be struggling. Be kind to the kit and it will repay you.

 

[timbrr]

For those that asked have been trying to decide on which Orange tractor to get the L series has the 25hp 33 and 39. All the same frame. Just wantframe make sure I wasn't paying extra for the extra hp if it didn't help

I bought an orange tractor a couple of years ago to help develop and maintain our 22 acres. I originally was considering something in the 32-38 (now 33-39) range. Ended up getting an MX5100 HST. Haven't regretted it at all.

"Hill Climbing Speed" is only one factor you should be considering in your purchasing decision. When you have a 38 and 46 side-by-side the most obvious difference is the wheel size. Traction is important — big wheels give more traction. Then, when you put a 46 and a 52 side-by-side you notice that the 46 has a prominent rectangular cover on the floor of the work platform (between where your legs will be, over the drive shaft). The 52 has a much lower and beveled cover. Ergonomics are important — having a clean platform makes life more comfortable and helps reduce the risk of tripping.

Having had a couple of years to live with my decision, I now realise I would have been miserable with a smaller machine. HST and big tyres are highly, highly desirable if you're doing significant amounts loader work on loose (e.g. sandy) soil. A clean platform is highly desirable for anyone, but especially those who are taller (and have long legs).

The MX5100 HST happily mows a 4% incline with a 5' rotary cutter at 2400RPM in Medium gear at maximum speed (the pedal's on the metal). It pulls overflowing buckets of sand, clay and gravel out of a pond with the 5' bucket up a 15% slope also in Medium (albeit much slower), but with the pedal only pushed down about a third of the way.

So, whilst horses aren't the only things that matter, horses are good. More horses are better. Not picking 'the largest possible' implement size that can be attached to your tractor also makes a huge difference to how well it copes with performing a task. Maximising implement size is not always a good strategy — especially if you want your tractor to remain 'nimble'.

PS: The MX5100 was effectively the same price as the L4600. Sometimes you can cross-grade into a different class at no cost.

 

[marhar]

My father in law let's me use his 25hp HST tractor quite often. Some of it's use is maintaining the road we live on. It really struggles going up any kind of hill especially with a load of gravel. I know the engine hp doesn't affect lift capacity because it's really based on what the hydraulic pump can do. But what about a HST transmission. Really not that familiar with how those work. Are they hydraulically driven. Basically I'm asking about it I buy a tractor and get a 40hp or so engine will that alleviate the issue of not being able to pull hills very well

I am sure some others know more than I do. That being said, with a shifted gear transmission in low gear I will lose traction before I "bog the tractor down". The tries are filled and will dig in the ground but if the tractor cannot move something it will not struggle. (This happens if I am doing something like trying to pull a stump). I realize your transmission is HST. If it is working correctly it should not shift up if the tractor is struggling.

 

[DieselBound]

Torque is what makes things happen. HP is what keeps things happening. (my lawn tractor is a 24hp gas engine; my B7800 is 30hp diesel and there's ZERO comparison- not because of the HP difference, but because of the torque difference [and, well, yes, the B7800 is industrial-like by comparison])

Power is, as some have correctly stated, about the equation of getting work done in a given amount of time. Look at my avatar, that's a Kubota B7800; that 30hp tractor (small frame) has done some incredible amount of work (now 1,800 hrs on it- I've put on about 1,050). It really comes down to ensuring that you're biting off what you can chew. I can bog down the Kubota just as I can bog down my Kioti (25hp difference); while the ease(?)/rate of bogging down might be greater than a geared tractor it still comes down to how much are you trying to chew at one time. I've hauled MANY 10k to 13k loads behind my Kioti; I've done so slowly- when you're pushing/pulling a lot of weight it's silly to look to do so with speed in mind in MOST situations (yeah, I get it, getting down a public road at a reasonable speed is a good thing- I regularly get behind many such tractors around me that are running with loads on the roads- when you're operating as such it is almost always with a pretty big tractor). I'll note that on my property there's NO way you can travel fast due to the terrain (too bumpy): this applies to ANYTHING I want to run over my ground, not just my tractors.

When discussing loader work, shuttling buckets of material around, keep in mind that HUGE loaders aren't being used to run up and down hills with loads in their buckets: they're generally on flat ground and shuttling shorter distances. Heavy loader work is tough on equipment.

If one is expecting to primarily do ground-engaging work then a geared tractor is almost certainly the way to go (and it's the only way once you get out of the CUT range). My HST tractors have done a LOT of ground-engaging work, not optimally, but they've done it; the majority of other tasks well offset such penalties from this more limited role/activity.

My B7800 does things that my NX5510 cannot. And, my NX5510 does things that my B7800 cannot. Although I now use my NX5510 more than my B7800 I have NO plans for letting go of the smaller tractor. Also, my wife is able to operate either machine thanks to both being HSTs (our UTV is also HST- that was the reason I got it, for ease of operation for her). Having fairly flat land makes HST weaknesses less sufferable.

Breaking things on bigger tractors costs a lot more than breaking things on smaller tractors!

Know your needs. Shoot for a good 80% match. Rent additional power as needed: reduce the risk of breaking more expensive equipment- breakages happen at times other than under work loads [don't ask!]).

 

[sd455dan]

my 2 cents, and not getting into Hydro versus manual

Horsepower is Calculated...

TORQUE is Measured... and is the resultant Moment of Force applied at a distance -the lever effect, and actual twisting Force.

Take two tractor engines both rated at the same Horsepower- but at different RPM for their rated "Power" all else being equal give me the one with the lower Rated RPM. it will produce more torque.

Put a high load in ground engagement work and the tractor with the lower RPM but same HP rating will fare better at Lugging that ground engaging implement when things get harder going through that tough ground . YMMV

ps Interesting thread on Torque rise on diesels and how it can help keep things moving

https://www.turbodieselregister.com/threads/curious-about-torque-rise.80829/

 

[Larry D Johnson]

My father in law let's me use his 25hp HST tractor quite often. Some of it's use is maintaining the road we live on. It really struggles going up any kind of hill especially with a load of gravel. I know the engine hp doesn't affect lift capacity because it's really based on what the hydraulic pump can do. But what about a HST transmission. Really not that familiar with how those work. Are they hydraulically driven. Basically I'm asking about it I buy a tractor and get a 40hp or so engine will that alleviate the issue of not being able to pull hills very well

I used to have a 45 HP manual **** tractor. I have a 66" snowblower that goes in the back but you drive forward with it. When I got into heavy snow I would have to downshift the tractor to the next lower gear. Three years ago I sold that tractor and bought a Kioti 35HP HST tractor. Now when I get into heavy snow I simply back off the peddle a little and it will go right through it even with 10 HP less than the old tractor.