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.