Easy question. My little Kubota B7510 has a roughly 20 HP diesel engine. My uncle's riding lawnmower, from Sears I think, has a 25 HP gasoline engine. My tractor engine looks a whole lot more serious than his lawnmower engine. Does his REALLY have more power, or are they rated differently?
HP vs HP
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DaveNay
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I believe thet the torque vs. rpm curve is more important than an "arbitrary"* horsepower rating.
*I say "arbitrary" because the hp rating that is printed on a sticker slapped on the side of the equipment is created by the marketing department.
Here is a pretty good explanation of how it all figures together.
Dave
*I say "arbitrary" because the hp rating that is printed on a sticker slapped on the side of the equipment is created by the marketing department.
Here is a pretty good explanation of how it all figures together.
Dave
Gatorboy
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</font><font color="blue" class="small">( Does his REALLY have more power )</font>
If you are talking Horse Power, then yes, he has more.
If you are talking Horse Power, then yes, he has more.
Bob_Skurka
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Much of the actual power of a tractor comes from the gearing of the machine.
I have a car that has about 300hp, I have a fleet of diesel trucks that have about 175hp. Which will haul more weight? The diesel trucks have the ability to pull loads in the 30,000 pound range, but my Avanti convertible would likely burn out the transmission trying to move that amount. This is very similar to the garden tractor versus CUT question.
There are also some serious torque issues involved, as previously mentioned. The garden tractor will have minimal torque compared to the CUT, which effectively means it will be unable to transmit the power to an implement or the wheels or both. For example: consider a high speed drill, they typically have very low torque and it is pretty easy to get the bit stuck in a fairly thin piece of metal when drilling, but a drill with greater torque and lower power can easily drill through the same material without binding.
There are also some additional issues as well, such as transfer efficiencies. A hydrostatic transmission is slighly less efficient than a gear transmission and consequently a tractor with a HST tranny will put 1 or 2 hp LESS to the PTO than will a tractor with a GEAR transmission. That said, your uncle likely has a glorified fan belt that drives off a spindle at high speed and is reduced down to run the rear wheels and the mower deck. SHORT OF MENTAL TELEPATHY, it is probably the least efficient way to transfer power I can think of.
So, a garden tractor may need more power simply to do less work because of a combination of the above factors because many things conspire against its abilities. And most of the reasons are cost related. It is often cheaper to up the HP of the tractor than to put in a more efficient transmission, gearing, etc.
Further, much of the reason I think (MY OPINION ONLY) for garden tractors having such large HP engines falls into the TIM TAYLOR line of thinking. If 12 hp is good, then 24 is TWICE as good! ARG! It is simple marketing. Give the caveman more power and stroke his ego.
I have a car that has about 300hp, I have a fleet of diesel trucks that have about 175hp. Which will haul more weight? The diesel trucks have the ability to pull loads in the 30,000 pound range, but my Avanti convertible would likely burn out the transmission trying to move that amount. This is very similar to the garden tractor versus CUT question.
There are also some serious torque issues involved, as previously mentioned. The garden tractor will have minimal torque compared to the CUT, which effectively means it will be unable to transmit the power to an implement or the wheels or both. For example: consider a high speed drill, they typically have very low torque and it is pretty easy to get the bit stuck in a fairly thin piece of metal when drilling, but a drill with greater torque and lower power can easily drill through the same material without binding.
There are also some additional issues as well, such as transfer efficiencies. A hydrostatic transmission is slighly less efficient than a gear transmission and consequently a tractor with a HST tranny will put 1 or 2 hp LESS to the PTO than will a tractor with a GEAR transmission. That said, your uncle likely has a glorified fan belt that drives off a spindle at high speed and is reduced down to run the rear wheels and the mower deck. SHORT OF MENTAL TELEPATHY, it is probably the least efficient way to transfer power I can think of.
So, a garden tractor may need more power simply to do less work because of a combination of the above factors because many things conspire against its abilities. And most of the reasons are cost related. It is often cheaper to up the HP of the tractor than to put in a more efficient transmission, gearing, etc.
Further, much of the reason I think (MY OPINION ONLY) for garden tractors having such large HP engines falls into the TIM TAYLOR line of thinking. If 12 hp is good, then 24 is TWICE as good! ARG! It is simple marketing. Give the caveman more power and stroke his ego.
crown
Platinum Member
As others have metioned the HP on the machine is marketing, hook your tractor to his tractor and have a pulling match you will easily drag him around your yard without any effort. /forums/images/graemlins/laugh.gif
Bob_Skurka
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crown, great idea, but drag him around on HIS yard because his wheels will be spinning while you drag him around and there is a good possibility that the spinning will tear up his lawn.
crown
Platinum Member
You make a good point!!! /forums/images/graemlins/smile.gif
lablovers
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Bob,
You have an Avanti? Pictures man I need to see pictures. /forums/images/graemlins/grin.gif
You have an Avanti? Pictures man I need to see pictures. /forums/images/graemlins/grin.gif
L
LarryRB
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th3e Avantis built in Ohio, weren't they built on modified Pontiac Firebird frames?
L
LarryRB
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the Avantis built in Ohio, weren't they built on modified Pontiac Firebird frames?
Gatorboy
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Larry,
Instead of writing the same post out again with a type-o correction, it would have been better to just "edit" your first one.
Instead of writing the same post out again with a type-o correction, it would have been better to just "edit" your first one.
jinman
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</font><font color="blue" class="small">( SHORT OF MENTAL TELEPATHY, it is probably the least efficient way to transfer power I can think of. )</font>
What a great statement! /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
I'm gonna "steal" that and use it 'til I wear it out. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
What a great statement! /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
I'm gonna "steal" that and use it 'til I wear it out. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
Gatorboy
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</font><font color="blue" class="small">( As others have metioned the HP on the machine is marketing, hook your tractor to his tractor and have a pulling match )</font>
I think the reason for buying the lawn tractor was to cut grass -- not enter pulling contests. I'm sure the higher HP helps in the cutting through tall or thick stuff.
I hardly believe HP is used for marketing reasons. My Scag 48-inch walkbehind is offered with 15 to 18 HP engines. I will guarantee that an 18 HP engine will be able to cut faster, taller and thicker grass without bogging down than with the 15 HP.
I think the reason for buying the lawn tractor was to cut grass -- not enter pulling contests. I'm sure the higher HP helps in the cutting through tall or thick stuff.
I hardly believe HP is used for marketing reasons. My Scag 48-inch walkbehind is offered with 15 to 18 HP engines. I will guarantee that an 18 HP engine will be able to cut faster, taller and thicker grass without bogging down than with the 15 HP.
Bob_Skurka
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Gatorboy, I was referring to the high horsepower MTD-Craftsman-and similar units, typically sold at box stores, typically sold as value priced units in the $850 to $2000 price range, that seem to be in the range of 22-to-25 hp with little 48" or 52" mower decks. A Scag can use lower hp and probably cut a heck of a lot better, but at a higher price, but I was not referrring to the upper grade equipment with my comment.
As for the Avanti being built on a Firebird frame, that is not my understanding, it is my understanding that some of the models were built on modified Monte Carlo frames. After the inventory of Studebaker engines was used up, they switched to Corvette & Camaro engines. The Convertibles got the lower hp Camaro engines because the are a bit too flexible to handle the torque of the Corvette engines.
Jinman . . . feel free, but if you get rich and famous using it make sure you give me credit in some footnote somewhere.
As for the Avanti being built on a Firebird frame, that is not my understanding, it is my understanding that some of the models were built on modified Monte Carlo frames. After the inventory of Studebaker engines was used up, they switched to Corvette & Camaro engines. The Convertibles got the lower hp Camaro engines because the are a bit too flexible to handle the torque of the Corvette engines.
Jinman . . . feel free, but if you get rich and famous using it make sure you give me credit in some footnote somewhere.
Soundguy
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There was a big discussion about this a while back.
For one.. your 20hp engine probably easilly produces that, and is rated to run at that 'usefull' hp. The 25 hp number listed for that lawn tractor may have been with all accessories off the engine, and it produced that hp at some rpm right befoe the engine detonated on the test bench... in other words.. a very unrealistic number.
When I first moved into the horse community I lived in 4 years ago.. I had this same discussion with a neighbor across the street.. he had a big huskie 25 hp machine.. and my little ole' 21ish hp yanmar 1700... he wanted a tug of war... Lets just say i pulled him around his pasture till he had a sad look on his face... even in high gear...
Weight will also be a concern. Even IF a lawn tractor could put 25 hp to the wheels.. if it only weighed 800 pounds... it would break traction before ever using it in a pull or ground engaging fasion..
Soundguy
For one.. your 20hp engine probably easilly produces that, and is rated to run at that 'usefull' hp. The 25 hp number listed for that lawn tractor may have been with all accessories off the engine, and it produced that hp at some rpm right befoe the engine detonated on the test bench... in other words.. a very unrealistic number.
When I first moved into the horse community I lived in 4 years ago.. I had this same discussion with a neighbor across the street.. he had a big huskie 25 hp machine.. and my little ole' 21ish hp yanmar 1700... he wanted a tug of war... Lets just say i pulled him around his pasture till he had a sad look on his face... even in high gear...
Weight will also be a concern. Even IF a lawn tractor could put 25 hp to the wheels.. if it only weighed 800 pounds... it would break traction before ever using it in a pull or ground engaging fasion..
Soundguy
lablovers
Silver Member
Bob,
I know we are supposed to be talking tractors here, but the Avanti is an automobile icon. I grew up with a father and step-father in the car business and have a deep appreciation for the classics.
The 9/11 connection to your car gives it a special place in the heart. Just reading your post brought back some powerful memories. The thought it belonged to someone killed on 9/11 gave me goose bumps. Good luck with the car, and give it the care it deserves.
I know we are supposed to be talking tractors here, but the Avanti is an automobile icon. I grew up with a father and step-father in the car business and have a deep appreciation for the classics.
The 9/11 connection to your car gives it a special place in the heart. Just reading your post brought back some powerful memories. The thought it belonged to someone killed on 9/11 gave me goose bumps. Good luck with the car, and give it the care it deserves.
Bob_Skurka
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The Avanti spends most of its life in storage, but I bring it out on sunny days in the summertime. It gets into a fair number of parades alternating between some politicians and various groups of high school cheerleaders. Prior to me getting it, the car was very lightly used, and for much of its life was a trailer queen being towed back and forth to car shows where it was a regular award winner. I'm not a big fan of show cars, I believe if you own it you should drive it. And I love to drive it. A guy who owns a string of car dealerships was tooling around in his Ferrari and he stopped it in the middle of the road to gawk at the Avanti. It is a joy to own and a great thing to drive. I find that men really are drawn to the car, it is not flashy enough for the ladies, but guys go out of there way to talk to me about it.
One of the most bizarre experiences I had was when I was driving home on a divided 4 lane rural highway. At a stoplight a group of about 40 Hells-Angle types surrounded the car. For a while I thought that the police would find me on the side of the road dead, but the bikers (and these were NOT the weekend biker-weekday accountant types) seemed to appreciate the car and several asked questions and talked to me. We sat through a full red light-green light-red light cycle (because they had me surrounded and I couldn't move) but they finally went on their way and I went home and checked my shorts to see if they needed to be changed!
BUT SOMEHOW I THINK WE ARE WAY OFF TOPIC
One of the most bizarre experiences I had was when I was driving home on a divided 4 lane rural highway. At a stoplight a group of about 40 Hells-Angle types surrounded the car. For a while I thought that the police would find me on the side of the road dead, but the bikers (and these were NOT the weekend biker-weekday accountant types) seemed to appreciate the car and several asked questions and talked to me. We sat through a full red light-green light-red light cycle (because they had me surrounded and I couldn't move) but they finally went on their way and I went home and checked my shorts to see if they needed to be changed!
BUT SOMEHOW I THINK WE ARE WAY OFF TOPIC
Currmudgeon
Gold Member
</font><font color="blue" class="small">( I have a car that has about 300hp, I have a fleet of diesel trucks that have about 175hp. )</font>
Reminds me of a discussion I had years ago with a sports car snob sneering at my truck.
"I'll drag you, but under my rules."
<Lighting up> " Really? OK! What are the rules."
"We face the vehicles in opposite directions and run a log-chain between the back bumpers. Then we see who drags."
Reminds me of a discussion I had years ago with a sports car snob sneering at my truck.
"I'll drag you, but under my rules."
<Lighting up> " Really? OK! What are the rules."
"We face the vehicles in opposite directions and run a log-chain between the back bumpers. Then we see who drags."
We had a long talk about this a month ago or two.
If summarize it (without referring the old thread);
Power (HP) is a kind of unit of Energy (E) which is a multiplication of Speed (S) and Force (F) or Torque (T).
This means "some" of your HP energy is spent on the Speed and "some*" of HP (Energy/Time) is spent on Force/Torque.
In the cars, most of HP is spent on the speed while in tractors most of it is spent on Force that does the Work.
If summarize it (without referring the old thread);
Power (HP) is a kind of unit of Energy (E) which is a multiplication of Speed (S) and Force (F) or Torque (T).
This means "some" of your HP energy is spent on the Speed and "some*" of HP (Energy/Time) is spent on Force/Torque.
In the cars, most of HP is spent on the speed while in tractors most of it is spent on Force that does the Work.
