What is the difference

I was talking with my wife and we were talking horse power in tractors.
We both were not sure.

What is the difference between a 25 horse power kohler engine cub cadet
and
a 20 horse power john deere 850?


What is the difference in the horse power. Just not understand why one can pull a plow and another could not.

Weight is the big difference. What could a 20 HP steamer pull?

The other difference is engine vs PTO power. PTO is typically
about 20 percent less than engine. Most of today's tractors are
sold on engine power, it sounds bigger.

Old tractors, hp was measured at the wheels, pto, or pulley accounting for all frictional losses.

25 hp Kohler is measured at the engine.

Then what throws people is the pulling force. If you gear something down, a small engine can generate a large force.

An example of getting a lot of force from a small engine is hydrostatic tranny or hydraulics on a log splitter. Whenever you generate a large force, you slow the speed. The more you slow it, the greater the force.

Then Briggs got in trouble for inflating hp numbers. So you can't always believe what you read. Another example of inflating hp rating a shop vac, 5 hp shop vac, 120v and 15 amps, numbers don't add up.

Got it? Test tomorrow.

Another very big difference is the torque that the
engine produces. Diesel will give you a lot more
useable torque and much better fuel efficiency.

Diesel gives better fuel efficiency only. It offers NO more torque and even less horsepower then a gas engine when bore and stroke is the same and aspiration is the same. There used to be many engines around that were built on the same format and offered in gas and diesel versions. Gas always had more horsepower and the same torque curve.

Up to about 50 horse. Beyond that diesel will totally pull the lugs off a gas engine tractor.

Allan

That 78 cubic inch Yanmar in the "Deere" is rated
nearly 30 gross horsepower. You are comparing PTO
horse specs with the Deere/Yanmar to the Kohler
that is only rated with the "gross" HP spec. It's
an apples to oranges comparison. It is a truly
bogus comparison. The "small engine" Kohler is
rated with the J1940 gross spec and NOT the Yanmar.

I"m still not sure I understand. My 1950 "H" Farmall displaces 152 cid, produces about 24 HP. My Massey 240 3-cylinder Perkins diesel also displaces exactly 152 cid, but produces 48 HP. Twice.
As I understand this, HP is the RATE of performing work, torque is the leverage.
I still don"t quite get it.

The displacement for a given amount of time is probably different. If the old engine turns just half as fast with the same cubic inches, then it probably produces about half the horsepower, but about the same torque.

Nonsense. Show me even one example. Here are few to the contrary including the famous Ford IH 7.3 diesel when it was a gasoline engine. Long stroke makes torque as does a lot of turbo-boost. Gas or diesel.

7.3 diesel in Ford trucks was made from the IH MV446 gas engine.

Ford-IH 7.3 diesel (445 cubic inches), no turbo: 185 HP @ 3000 RPM, 360 lbs. max TQ @ 1400 RPM. 4.1" and stroke 4.18"

IH gasoline 7.3 (446 cubic inches), no turbo, 235 net hp at 3600 rpm, 8:1 compression ... 385 lbs. max torque at 2600 RPM, 4.125" bore x 4.18-"stroke


Oldsmobile 5.7 (350) diesel - 120 HP @ 3600 RPM and 222 TQ @ 1900 RPM
Oldsmobile 5.7 (350) gas engine - 170 HP@3800 and 275 ft/lbs of torque @ 2000.
Both 4” bore X 3.38” stroke


Tractor engines with equal sizes in gas and diesel (same bore and stroke):

Hercules DD and GO engines (Oliver)

130 gas: 30 horse, 97 lbs. torque @1400 RPM
130 diesel: 30 horse, 96 lbs. torque @1200 RPM

Hercules 133 c.i. engines (IXB and DIX4B)

133 gas 43 horse @ 2600 RPM, 92 lbs. torque @ 1800 RPM, 3 1/4" bore by 4" stroke. IXB engine.

133 diesel 45.5 horse @ 3000 RPM, 96 lbs. torque @ 1500 RPM, 3 1/4" bore by 4" stroke. DIX4B engine

Continental 157 c.i. engines (G157 and GD157)

157 c.i. gas 37.7 horse @ 2000 RPM, 121 lbs. torque @ 2000 RPM. 3 3/8" bore X 4 3/8" stroke.

157 c.i. diesel 37.5 horse @ 2000 RPM, 109 lbs. torque @ 1200 RPM. 3 3/8" bore X 4 3/8" stroke.

Waukesha 135 GK and DK engines:

426 c.i. gas: 138 horse @ 2400 RPM, 264 lbs. torque @ 1200 RPM. 4 1/4" bore by 5" stroke.

426 c.i. diesel: 140 horse @ 2400 RPM, 259 lbs. torque @ 1600 RPM. 4 1/4" bore by 5" stroke.

Buda 153 c.i. engines (4B153 and 4BD153)

153 c.i. gas, 49 horse @ 2800 RPM, 112 lbs. torque @ 1500 RPM, 3 7/16" bore X 4 1/8" stroke.

153 c.i. diesel, 40 horse @ 2400 RPM, 102 lbs. torque @ 1400 RPM, 3 7/16" bore X 4 1/8" stroke.

Here are a few examples of tractor engines with equal sized power ratings in gas and diesel with different sized engines - and also two equal sized in gas and diesel:

Deere 2010 (and 1010 with diesel version)
Note that both 145 engines are equal bore and stroke, and the gas has more torque)

145 gas: 39 horse, 114 lbs. torque @ 1500 RPM
145 diesel: 36 horse, 95 lbs. torque @ 1500 RPM
165 diesel: 46 horse, 119 lbs. torque @ 1500 RPM
Those are specs published by Waukesha. The gas 426 runs 6.2 to 1 compressoin ratio. Diesel runs 17.5 to 1. Horsepower is stated as "rated horsepower" and torque as "maxium torque - RPM."
So the 426 diesel runs a max torque of 259 lb. ft. at 1600 RPM.
Gas 426 264 lb. ft. @ 1200 RPM

Mack had a pile of long-stroke gas engines.

707 cubic inch gasoline Mack had 5" bore by 6" stroke. 232 horse @ 2100 RPM and 617 lbs. of torque @ 1200 RPM.

707 cubic inch diesel Mach had 5" bore by 6" stroke. 201 horse @ 2100 RPM and 602 lbs. of torque @ 1500 RPM.

Mack's "little” 464 in gas and diesel:

464 gas engine, 464,cubic inches, 4 7/16" bore by 5" stroke, 185 horse @ 2800 RPM and 380 lbs. torque @ 1400 RPM

464 diesel engine, 464 cubic inches, 4 7/16" bore by 5" stroke, 140 horse @ 2600 RPM and 325 lbs. torque @ 1800 RPM

The key differentiator is weight.

It takes x horsepower to pull a plow of a given width in a given soil to a given depth at a given speed. However, that is horsepower AT THE DRAWBAR. Tractors are typically rated by PTO horsepower, which is pretty close to net engine horsepower. But tractors differ widely in how efficiently they can convert engine horsepower to drawbar horsepower. The JD 850 is rated at 22 PTO HP and 19 HP at the drawbar. So it can get 86 percent of its horsepower to the ground. It can do that because it weighs around 2400 lbs, maybe more with ballast.

Now if we look at the top-of-the line Cub Cadet, the GTX 2154, it has an engine rated at 22.5 horsepower, fairly close to the JD 850. But how much does it weigh? I'm guessing less than 1000 pounds. You could probably get it up to 1000 pounds with ballast. So it's at a huge disadvantage to the JD on weight alone. Plus the 850 would likely have agricultural tires, while the Cub Cadet is on turf tires, which offer very little traction on soft ground. How much of that 22 engine horsepower can the Cub Cadet get to the ground? At plowing speeds, say 2 to 4 mph, my guess is it would be doing good to get even 5 drawbar horsepower. And let's say you managed to add enough ballast to get the Cub Cadet up over 2000 lbs. It's unlikely the drivetrain components were designed to handle forces generated by 20 drawbar horsepower; something would break.

So why does the Cub Cadet even need a 22 hp engine? Well, its primary purpose is mowing. Mowing takes a lot of power, and it can deliver almost all of its engine horsepower to the mower.

The Farmall H made 28 belt horsepower when rated at seal level. It was only spinning at its max of 1650 RPM. The MF with the Perkins would not of done any better if only tested at that low engine speed. The 240 was rated at 2250 RPM.

Another element is the old engine's durability under full load (or even the 850 maybe). If you ran the 25 h.p. Kohler constantly maxed out it wouldn't last. Reminds me of top fuel drag engines. They can make extreme power (some say 8000 to 10,000 h.p.) for a few seconds, after that look out.

Those figures are more out of whack today then ever
before because of all the different ways they figure just to
goof with you.

FWIW: Our JD 750 was only be like 18 hp but when on a
dyno made more like 24. And in real world dragging things
around could match or out perform a JD B and a Ford
Jubilee. 4x4 on one makes a world of differance on these
compacts.

The difference is the torque rating at what RPM.
Torque is related mostly to displacement and a
typical tractor engine produces the max torque at
a low rpm 1500-1800 rpm. Crank them higher and
they will produce more horse power but less
torque. The little Kohler rated horse power is at rated at
about 3600 rpm which is well above the torque peak
and because it is a rather small displacement the
torque (work effort) is no where near the 20 hp JD
or my 9N rated about 23 hp or my 12 hp Cub.

My old JD 400 mower only has 19 hp but has a
displacement of about 750 cc. Compared to the 23+
ratings on current mowers with about 480 cc. The
400 does just fine with a 60" deck while the the
normal 480 cc higher HP mowers struggle with a 54"
deck.
















0

Torque is measured whereas HP is calculated from a formula of torque and RPM.

You can pull a train with a mouse IF you gear him
right a small engines power no matter what it is
can be doubled or more with gearing and that is
called a transmission --thus drawbar horsepower or
pto horsepower (a point to ponder)

I would agree with the others, apples to oranges. You have to get the HP to the ground at a speed that is useful.

Chassis length, width, weight and tire sizes.
HP is the rate of work.
Put both of them on a pto dyno the 25HP engine does more work than a 20HP engine per hour.

There are those who talk torque, torque, torque and torque is what gets the work done. Apparently they are more evidence in the failure of the education system to teach the basics . HP = torque ftlbs X rpm / 5252 .

A lightly loaded diesel burns more fuel per HP hr than a modestly loaded gasoline engine. Have you never looked at the Nebraska tractor tests?
Diesels pay when working under constant heavy loads loads for extended periods of time.

I looked at few of the responses and they are very correct.
Statement A: Would you rather have a 25HP cub cadet mowing tractor that weighs 700 lbs. OR-- a 25 HP New Holland Diesel that weighs 1700 lbs.
It also comes down to gearing/engine RPMs, Those garden tractors are rated at 3600RPM, the Compact diesels are rated at 2600 RPM, with Waaay more engine torque.

It all comes down to Torque and Weight.
If you are a super tough guy that that can bench press 300 lbs, Ok--Fine, but if you only weigh 140 lbs with big arms, a guy that weighs 250 lbs and can only bench press 300 lbs can grab you, throw you and sit on and crush you.

To do any real farm work with any tractor you need weight, and the torque supplied by a farm tractor engine will do the work,,,,with the weight of the tractor. Try pulling a 2 bottom plow through topsoil with a cub cadet mowing tractor that you got from Home Depot.

I believe a simpler way to ex-plane this is if you substitute the word weight for torque. The engine alone produces torque not the whole tractor. Therefor the heavier the engine components, the more torque produced. Heavier crank, heavier pistons, heavier flywheel etc. More torque alone will not enable it to pull the plow so now you have to add to it some weight on the tractor. Oh man now I see this explanation is not simple at all.

From the Washington Post comes clarification in simple terms:
.... In some cases, the lawsuit alleged, identical engines were labeled with different horsepower ratings, leading consumers to believe they were getting more power by purchasing more expensive models.

Briggs advertised one engine as having 6.75 horsepower and yet told the Environmental Protection Agency the same engine had 3.6 horsepower, an 88 percent overstatement, according to the lawsuit.

At least since 1997, the engine manufacturers Briggs, Tecumseh, Kohler, Toro and Kawasaki have reported horsepower ratings to the EPA that were significantly lower than the ratings advertised to the public, the lawsuit said.

For Briggs, it wasn't an attempt to mislead anyone, according to Thomas R. Savage, a senior vice president at the company.

There are different testing protocols for the EPA than for the general public, Savage said. The EPA ratings are based on a "composite" of test results at different engine loads, while results for the public are based on an engine's full-power capabilities.

An Illinois judge dismissed the suit in March, but it may resurface.

"It's still not totally resolved because the judge did not tell us what portions of the suit he dismissed with prejudice or not. So in effect, it allows the lawyers to come back," said James E. Brenn, Briggs's chief financial officer.

Over the years, manufacturers in the intensely competitive small-engine business have used horsepower ratings as a marketing tool.

"Horsepower sells," said Jeff Hebbard, a vice president at Ariens, a manufacturer of lawn tractors and other outdoor power equipment in Wisconsin. "It doesn't always sell for the right reasons, but it does sell."

The horsepower race sounds like what has occurred with electric motors, where power claims have been embellished, said Kevin Brady, a Minneapolis lawyer and engineer not affiliated with the horsepower lawsuit.

"You can exaggerate a bit and not get in trouble," Brady said. "It's called puffing."

Jim Nicholson states what follows:
In reality hook it to a dyno and crank it up to the max and load it till it produces a real graph of HP and torque. Look at the graph. It will not tell you which one will last longer, it will tell you which one is more powerful. If you also measure the fuel used while on the dyno at every point on the graph, and assuming the fuel is correct for the engine, the coolant temps are correct, and the engine lubrication is nominal, and atmospheric pressure and humidity are controlled as well as ambient air temperature, and the engine is connected to intake filtration as it would be in the equipment, it might provide real information.
I know a guy that claims to be able to jump flat footed over a 5 foot fence. I think he exaggerates some. Jim

B&D,What is reason then that a 3010-3020 can't stay in the field with a 720-730 on the same load,tires,weight unless the 30XX is turbo'd and then it can't keep up with a 4020 with everything being the same.Or a Farmall 460 can't stay with a SM?

All tractors are bound by the same laws of physics and thermodynamics, which haven't changed since the days of James Watt. If tractor A outperforms tractor B under certain conditions, it is given that tractor A is producing greater drawbar horsepower. Whether or not its engine torque is greater is besides the point.

or in the case of the 4020, the gas had smaller engine but same rated hp.

(quoted from post at 13:46:39 03/15/14) B&D,What is reason then that a 3010-3020 can't stay in the field with a 720-730 on the same load,tires,weight unless the 30XX is turbo'd and then it can't keep up with a 4020 with everything being the same.Or a Farmall 460 can't stay with a SM?

Click to expand...

Put them on a pto generator and compare.

There are some people that can't tell torque, from HP, from Torque rise.

What I said is a 67hp 3020 will not keep(match) up with a 56hp 72-730 in the field,with like load-tires, weight.So the question is still not answered.HP is supposed to be HP,but since the 50s-60s,it hasn't been that way in real life.

You're going to have to explain to me where you got your test data. The only RELIABLE test data I'm aware of is from the Nebraska Tractor Tests. These tests try to replicate real-world conditions as accurately as possible. Partial data from the older tests is posted on tractordata.com.

John Deere 730 Diesel
Belt HP tested: 57
Drawbar HP tested: 52
<a href="http://www.tractordata.com/farm-tractors/000/0/5/52-john-deere-730-tests.html">http://www.tractordata.com/farm-tractors/000/0/5/52-john-deere-730-tests.html</a>

John Deere 3020 Diesel
PTO HP tested: 71
Drawbar HP tested (Syncro-Range): 61
Drawbar HP test (Powershift): 55
<a href="http://www.tractordata.com/farm-tractors/000/0/6/63-john-deere-3020-tests.html">http://www.tractordata.com/farm-tractors/000/0/6/63-john-deere-3020-tests.html</a>

So the Nebraska tests indicate the 3020 outpulls the 730. So your original premise is simply wrong. You may be convinced otherwise, but the data does not support you.

I have a question.

If I put a 2 bottom plow to my IH "H" and plowed ,say, a 1/4 of a mile.
Now I take my H--pull the motor and replace it
with a lawn mower motor of same HP and pull the plow same distance. Which one will get to the end first? That would be more like true comparison.

If that lawn mower engine was dynoed at the same HP as the H (not advertized HP), and the engine was geared to match the H engine full load speed so its (usually) much higher operating and rated HP RPM were driving the H at the same ground speed, they would match perfectly. Jim

No test data,just real life field facts.Neb.replicated nothing other then what could be done on a concrete pad.Too many people found out different when they put the tractors in the fields together.M&W is the only thing that saved Deeres butt in the 61-67 time period.Plus IHs in the same period.Case and Minnie Mo were the only ones that were not affected in that time period.(60 to 90hp.)But if you and B&D want to believe what is on paper instead of real life then I can't say anymore.

The 22 horse power Cub Cadet doesn't have the ability to pull or tow as much as the John Deere 850. As others have
stated the Cub Cadet figure is the rated horsepower of the engine, the John Deere is from a Nebraska Tractor test
demonstrating how much draw bar pull it develops. As for the comment about a Kohler not lasting as long running at
3600 RPMs, at rated RPMs they do okay for engine life, but probably won't run as long as the Deere engine run it
its' rated RPMs. When I worked at the golf course we could expect 3,000 to 4,000 hours on a Kohler K series engine
IF we took care of them (regular oil changes and cleaned the carbon out of the combustion chamber). Some gas farm
tractors didn't run that long, some much more.

Size verses horsepower, again to beat a dead horse some of that is from engines rated a different speeds. Some
industrial engines produce their rated power at lower RPMS which is a factor in them being able to run "forever" at
the rated speed and power. By forever I mean with out overheating and going into a failure cycle. An example is one
of my previous employers had a large pump that was powered by a Ford 4 cylinder "Lima" engine, think 2.3 Pinto, I
had another version of that same 2.3 liter engine in a Mustang with a turbo charger and electronic engine control
system. The one in the car put out a lot more horsepower, Don't think the car could run for hours on end at 6,000
rpm (where it was rated at 200 HP) the pump motor would run for days at 2,000 rpms. Ford offered 2.3 car four
cylinder engines ranging from 88 horsepower to 205. I had a 2.3 in a 1983 Ranger and have a 2.3 in an 1986 Mustang
SVO, the Mustang has twice the HP the Ranger did. The Ranger had a 1 barrel carburetor, the Mustang a turbo charger
& multi port fuel injection. The Mustang engine would run at 6,000 RPMs plus, I don't think the Ranger engine would
pull more than 4,000 RPMS

Variations on the motor will make a difference. Let's look at a 200 cubic inch engine. The Ford Model A was a 200
cubic inch engine and was rated at 40 HP. Ford made a straight six in the 60's it was rated at 120 horsepower
(overhead valves and turned faster). GM made a 200 cubic inch V6, the highest horsepower they offered was 170 HP,
Honda made a 200 CID V-6 with 200 HP. When I was in High School I had a '63 Pontiac with a 389 V-8 rated at 313 HP,
at the same time my Dad drove a truck with a 8V71 Detroit Diesel (568 CID) rated at 318 HP. Wouldn't want to drive
a Semi Truck with a 389 Pontiac in it and a Bonneville convertible with an 8V71 Detroit would be a dog.

I gotta agree with Mark on this one.
The reason for the Nebraska tests were because people/companies were trying to sell tractors with claims that were untrue.
So some smart engineers came up with a series of standardized tests to measure the actual work a given tractor could do. No inflated claims or unverifiable statistics.
Just the facts.
For me I will take the scientific results as verified by smart engineers over what Mike or Willy or Bubba say any day.
That doesn't mean you have to. Unless of course, you want to sell a new tractor in the state of Nebraska.

I called nnalert..She said "what difference does it make"

You are right on Neb.testing,but these newer tractors HP ratings don't hold up against the older tractor HP ratings on work being done.JD-Rs,80s,Case 500-600s.Massey 55-555s and etc.50HP tractors pulling 5-6 bottom plows where modern 60-70hp tractors won't pull 4 and keep up.Same in automotive engines too.

(quoted from post at 15:44:42 03/15/14) I gotta agree with Mark on this one.
The reason for the Nebraska tests were because people/companies were trying to sell tractors with claims that were untrue.
So some smart engineers came up with a series of standardized tests to measure the actual work a given tractor could do. No inflated claims or unverifiable statistics.
Just the facts.
For me I will take the scientific results as verified by smart engineers over what Mike or Willy or Bubba say any day.
That doesn't mean you have to. Unless of course, you want to sell a new tractor in the state of Nebraska.

Click to expand...

There are several variables here. JD had that very long stroke on their 2 cylinder diesels. Add in the massive weight of the flywheel and crank and they would do much more than the what the Nebraska test list. It's about the only tractor I know of that I think may have been cheated on the test.

Rick

Some of the difference is gearing. The Kohler runs at 3600 RPM? The Deere runs a thousand RPM's or so slower, as a guess. At 2 MPH the Kohler will be geared down farther than the Deere will at 2 MPH, creating more torque at the wheels. There are a lot more factors than that but it's an example. JIm

After all the Technicrats have weighed in with their long winded pained explainations all I can say is I can take a 20 HP Allis Chalmers B and drag a 25 HP Cub Cadet all over the place no matter what any one does to the Cub and the B won't break a sweat.

Speaking of gas vs diesel...
Click on the link for a PDF file on the Ford 3000.
They list the performance differences in the gas vs diesel engines.
What is not mentioned is the 3000 gasser is 158 CI
(4.2 bore X 3.8 stroke)
and the 3000 diesel is 175 CI. (4.2 bore X 4.2 stroke)
The gasser does turn 100 rpm faster.
PDF File

Correct you are,but in 8 hours the lawn mower engine would be toast. The H maybe quite a few years later. We've been through this whole thing before.

152 Perkins are almost identical whether gas or diesel.

(quoted from post at 05:22:06 03/15/14) I was talking with my wife and we were talking horse power in tractors.
We both were not sure.

What is the difference between a 25 horse power kohler engine cub cadet
and
a 20 horse power john deere 850?


What is the difference in the horse power. Just not understand why one can pull a plow and another could not.

Click to expand...

The simplest way to put it is that your "25hp" Kohler has wildly inflated HP numbers that are used for advertising purposes. If it was measured like it was back in the 60's and 70's it might be a 12 or 14hp engine. But they don't measure them like that anymore. That's why today you need a "8hp" engine to run a cement mixer that used to take a 1.5hp engine.

Yes . . . aren't facts a boring nuisance! Much better and fun just to guess at things and make judgments based on emotion and/or anecdotal events.

No experience beats what people read out of books that haven't tried to apply it in the real world.
You can argue fuel consumption all day from some data source or another but the only way to really compare two tractors is put them in the field with identical pieces of equipment and see which one burns the most fuel.