Horse Power Question

B

Brutalfly

Well-known member
Ok this might seem a little stupid or funny to some but I am trying to figure this out.
I have a cub cadet lt1050 mower with a 25 horse power kohler engine
The cub has a 9-10 horse power engine
I know that my cub cadet can't pull a plow like the cub can or do other things like the cub can
So why is it rated higher in horse power?
Is it because it spins the blades faster?
Can the cub do the work the cadet can't because of the weight?
I have asked this before on another website and got great answers but sometimes all of the jargon confuses me.
 
Depending on the year, the Cub's engine puts out 13 to 16 horse power.

Tractors are rated at horse power on the draw bar or belt pulley and normally not engine horse power. So, the 9 - 10 horsepower is draw bar rated.

Engine horse power is the result of a mathematical formula. Torque x rpms divided by 5252 equals horse power. An engine developing high to very high rpms and with low torque will have more horse power than an engine developing very low rpms and high torque.

Torque is grunt on the ground. Engine horse power is an indication of how fast the task can be accomplished.

Keeping things simple, one is rated at lawn mower horse power and the other is tractor horse power. If you want a lawn mower, go for engine horse power. If you want to accomplish some sort of farm related task, go for torque.
 
Don't know bout CC and plow, BUT my Allis 917-H will out plow my cub pulling Brinley 10" plows ---Did try that last fall here in gardens!---917 has 18 horse engine instead of 17, also has BIG rear wheel weights and big ole fat BAR tread tires on it! the reason for the pullin power is the fact that it takes HYDRO to maximize the speed/traction/rpm/and hp!---THAT is why I am converting one of my 48 cubs to HYDRO drive! thanks; sonny
 
One of the biggest differences however, is how they NOW rate small engine horsepower. Small engines are bench tested with no intake filter, no exhaust, no PTO clutch, and nothing attached to the drive shaft. So, a bare engine is bolted to a test stand, and run unhindered, to determine the "horsepower".

As mentioned earlier, a cub (and all farm tractors of the time) is rated at 9 horsepower at the drawbar. So, tractor built, assembled, complete with exhaust system, air intake filter, transmission, etc., then loaded down to determine how much it can pull.

These are COMPLETELY different methods to determine horsepower.

That 25-hp engine in your new Cub Cadet is likely more equivilant to a 7 or 8 hp farm tractor, a walk behind farm tractor. Probably less since the frame, wheels, transmission, etc., could not handle the load that an 8-hp farm tractor could.

Also, given the opposite, if you ran a cub C-60 engine on a bench with nothing attached to it, it would likely rate in at around 25 to 30 hp.

So, you really have to look apples to apples when comparing these things.
 
Thanks for the replies.
I think these have helped me understand more than any other answers I have ever gotten!
Thanks a million!!
 
Also, don't forget the fact that the garden tractor engine is usually turning at 3600 rpm to get the rated horsepower, while the cub engine is turning at 1800. I wonder which will last longer?
 
John,
That gets into a whole other set of variables. High RPM vs low RPM, air cooled vs water cooled, aluminum vs cast iron block, twin cylinder vs 4 cylinder, V block vs inline block, etc. LOTS of variables there!!! I can tell you however, an inline, water cooled 4-cylinder, cast iron block engine running at 1800 rpm will aparently last...... well..... it's looking like it will last forever.

However, an aluminum, air cooled v-twin running at 3600 rpm will typically last about 10 years or about 1000 hours, or until the first time you let her run a little low on oil!

Oh yea, that's another thing, a small engine holding about a quart of oil, vs a 4-cylinder with 3 or 4 quarts of oil in it. Again, wonder which will be more forgiving if you forget to check it????
 
One critical factor is the weight of the tractor. Of all the Nebraska Tractor Tests I have reviewed, the maximum horizontal pull measured in pounds is always less than the weight of the tractor (including any added ballast). And this is the case for both dirt and paved surfaces. Thus a heavier tractor with less horsepower can pull more, depending on the gearing of the drivetrain, than can a lighter tractor of greater horsepower. A Rumely OilPull 30/60 (30 horsepower drawbar. 60 horsepower belt) probably can pull more than a new 150 horsepower tractor. But the Rumely cannot pull it very fast. Much too slow to be practical for today's applications
I have a larger tractor which travels 1 5/8 MPH full throttle in first gear. With heavy ballast, it is amazing how much it will pull. But the ballast hinders it at higher speeds.
 
Eugene":spn2fk7p said:
........Torque is grunt on the ground. Engine horse power is an indication of how fast the task can be accomplished........
Click to expand...
Another way I have heard this explained is;
Torque gets you moving, Horsepower keeps you moving
 
Did horse power ever go up in the cub series?
Did it ever go up from the first year til 1964?
What about the International Cub until 1975?
Or
The New International Cub until 1979?
 
The later models had a little more horsepower, mainly from higher rpm governors, but they also had different cams, as well as domed pistons and larger manifolds and carburetors. the increase is not huge however. As was mentioned earlier, it would be fun to mess with a hydrostat on a cub, but all the hydrostats I have ever dealt with consumed a lot of power themselves. Maybe I misstated that, I guess what I should have said was they were not very efficient in the transmission of power.
 
John *.?-!.* cub owner":fwg4pg54 said:
The later models had a little more horsepower, mainly from higher rpm governors, but they also had different cams, as well as domed pistons and larger manifolds and carburetors. the increase is not huge however. As was mentioned earlier, it would be fun to mess with a hydrostat on a cub, but all the hydrostats I have ever dealt with consumed a lot of power themselves. Maybe I misstated that, I guess what I should have said was they were not very efficient in the transmission of power.
Click to expand...

The hydrostat would be an interesting thing to put on a cub. I wonder how out of place it would look.
So how different is a 1949 cub from a 1959 cub (not the low boy) not including obvious looks but the inside of the engine and everything internal?
 
Don't believe there's a lick of difference between a '49 and '59 engine. The "later models" John was referring to were built in the 1970's at the end of the Cub's production run.
 
Stanton":93085oiy said:
Don't believe there's a lick of difference between a '49 and '59 engine. The "later models" John was referring to were built in the 1970's at the end of the Cub's production run.
Click to expand...

Thanks Stanton.
I have been reading through the 1959 farmall manual and I plan on reading through some others from earlier years.
They are interesting reads. The cartoons are great
 
Brutalfly":3jye6pv9 said:
.....
So how different is a 1949 cub from a 1959 cub (not the low boy) not including obvious looks but the inside of the engine and everything internal?
Click to expand...
Serial number. LOL. A few cosmetic things such as shape of headlights and looks of the grill, but all parts and implements interchange.
some interesting reading for someone not totally familiar with cubs: Don't forget to go to page 2
http://www.atis.net/CubFAQ/cub_faq.html
 
My hydro design will make the cub look---well just like regular cub with hydraulic controls and NO clutch pedal/clutch/ or drive shaft! in the torque tube! thanks; sonny
 
There are differences between a '49 and a '59 engine.
In 1950, battery ignition became available. True, not an internal engine change, but the variable advance on the timing would make a difference with a bit of additional power. Engine RPM increased in '55, I'm imagine increasing the HP along with it. The Camshaft also changed in '55, and was the only it changed during the life time of the Cub. The Cam did not change again during the later years.
 
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