Does engine HP affect driving power

[JTMachineDesign]

I dunno.. buying a tractor with more HP will speed up the work, maybe.. but it will certainly speed up your debt

 

[sportscarclinic]

An HST transmission is not super efficient. At best about 80-85%, so that means out of the 25hp, you only have 20 or so HP available to the wheels. I have a 35hp Kioti with HST and a ‘53 NAA (30 or so at the PTO). I can easily pull a two bottom plow with my NAA in second gear. The Kioti bogs down pulling it in mid range and struggles/crawls in low range with the same plow.

I love the HST for bucket work, mowing and clearing snow but I should have accounted for transmission losses and gotten a 40hp to be on paar with my NAA but that would have put me into a bigger tractor. Something you should keep in mind.

"...not super efficient" I think "super inefficient" is much closer to the truth, but perhaps you are were just being diplomatic.

 

[Dennis Mohn]

You don't mention what manufacture tractor it is or if it is a yard and garden variety. Check to see if you have a setting that allows you to change the "speed" from Hi to low. You may just need to make a slight mechanical adjustment. Also you need to be running the engine at a minimum of three quarters throttle to full throttle and the engine needs to be maintained. You also didn't say if it was diesel or gas as this will make a difference also. I run a Steiner 430 with a small Kubota diesel and floatation tires and it will spin the tires and not bog down, in low range, under load as you describe. I will add I have never put it in high range even when roading

 

[Denco54]

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

your HST tractor is equipped with a High & Low power setting. When working hard you must use the Low setting, this will boost your power but slow the speed. Power is usually sufficient to climb a tree. I know cuz I own a 16hp B7100 Kubota & you would not believe the tasks it has performed.

 

[CH4Ohio]

Honestly, guys, I love HST. ESPECIALLY for loader work. My 30 HP HST Kubota B2910 has been the single handiest hard-working versatile piece of equipment I've ever owned. I've done everything with it -- including pushing a lot of snow, tilling, mowing, pulling hay wagons, backhoe attachment, etc.

I have a L5740 HST that I use with a 9' haybine, 23' hay rake, and square baler pulling an accumulator or hay wagon. In Medium range, you don't even know you're pulling anything. It's also carrying a FEL that I almost always leave on while doing hay work. Also have the rear tires loaded. It's a cab model so with all the accessories it's pretty much maxed out on weight.

With engine at proper RPMs and in the proper range, I find the HST to be very capable and dependable. I do all work in Medium range. About the only time I use LOW range on either machine is when tilling with a 5' tiller. Except for VERY light work, like pulling a hay tedder, I use HIGH range only for travelling on the road or similar smooth surfaces.

 

[chander]

Buy the biggest HP tractor you can afford, just like build the biggest garage you can afford. We outgrow them both in no time!

 

[RancherGuy]

Thanks for all the input. 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 have orange and have had orange tractors and understand what you are experiencing. I started with a 23 gear transmission, had a 38 HST and have a 37 GST.

I was extremely disappointed with the 38 HST (same as L3901 today). It was extremely noisy even after I replaced the transmission oil with recommended special Kubota oil. I hated it so much that I sold it with less than 100 hours. It had no power. The transmission seemed to suck every bit of power the engine could produce. My only choice was to use M range a lot more than I thought was necessary. Had a 60" shredder. Interestingly, it seemed that it had less power than the 1992 23 hp (engine) that I previously sold. That L2350 had over 5,000 hours and needed some mechanical maintenance work that I just didn't want to get into.

I now have a 2002 L3710 GST. An oddball of sorts in terms of the engine size. For the frame it is a step up in frame size from the L3301/L3901. I think it is the same machine as an L4400. The transmission is what is called GST. I really love this machine. The transmission is what I think of as a compromise between a gear transmission and HST. Some may think of the transmission as powershift. It has 8 speeds and left hand reverser. Shifting can be done with or without the clutch by simply selecting the desired gear. It soft-shifts into the new gear. Once shift is complete, it acts like a gear transmission with no power is lost through hydraulics. It has absolutely no problem pulling and easily works a 72" shredder. If I could not get GST, I would absolutely select a geared transmission every time.

 

[Max Power]

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

engine hp does affect all the work the tractor is able to do. whether it drives a hydraulic pump, HST or plowing a field. more hp allows more work to be done. the definition of horse power is "work done".

 

[rScotty]

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

Higher HP tractors also weigh more, so the problem with going uphill doesn't change much with simply adding HP. We've had a dozen or more tractors from 15hp up to 100 hp, and they all struggle going up hill - and expecially with a load. I think it's the way they are geared. Most of a tractor's work is at low speeds, so the designers optimize for low speed. As long as you can shift down to climb a hill, the designers don't seem to mind how slow that makes them go.

Of course the more gears the tractor has to chose from, the less it is going to struggle with hills.
The old fashioned geard drive tractors were efficient at getting HP to the wheels, and the GST shift is maybe the best combination of efficiency and convenience. Some tractors have the new 6 speed HST & it does pretty well, but basically they all tractirs struggle with hills - even our 100 hp turbocharged tractor won't even pull itself up any long hill at full throttle in high gear. Add any load - even half a bucket of dirt - and it's back into the medium gear range just like the others.
rScotty

 

[sportscarclinic]

engine hp does affect all the work the tractor is able to do. whether it drives a hydraulic pump, HST or plowing a field. more hp allows more work to be done. the definition of horse power is "work done".

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.

 

[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.