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Horse Power?

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Dutch
Doug, I wouldn't mind telling you why I like brussel sprouts. Maybe you should start a new message thread. Be fore-warned, these members have some weird tastes. Hope you have a strong stomach. I'm sure a few would even like the "can of worms".

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Brent_Baumer
Fact- I pull a 60" trail mower with a 13hp briggs behind either a 3416H (briggs) or a 916H (kohler). In thick, tall grass the trail mower readily boggs down and will even die unless I go at a snails pace. The tractors do not, even though they are powering a 48" deck, a hydro tranny, the weight of the tractor with me on it, and the trail mower. Hmmmmmm. Does 3hp and 12" of cutting width make so much difference? Brent

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Guest
How come, why does my old (1976)12hp kohler, seem so much stronger than my Newer vanguard 15hp, I understand differnces in transmissions and gearing and such but the 12 is bigger, WAY heavier, louder, uses more gas, (looks meaner) is horsepower a universal means of measuring torque or strength? How accurate is the measurement? Am i imagining things, Does anyone understand this question.

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Dutch
My old 12hp K-series Kohler also seems "stronger" than my 18hp Kohler Command. The 12hp "roars" while the 18hp is smooth and quiet. I can tell the 18hp really has more power when in actual use. The 18hp keeps the RPMs up long after the 12hp will "bog down". Horsepower ratings can be deceptive since there are different ways to measure. What one engineer measures as 15hp, another can measure as 16hp, and another as 14hp. Don't confuse torque with horsepower. Although usually related, those are two different measurements. Plus, torque can be multiplied through gearing, horsepower cannot. Your 250hp car can "jump" away from a stop light and be going 60 mph in a few seconds, but it couldn't pull an empty semi-trailer very well. A 250hp truck can pull a fully loaded semi very easily. The reason is the 250hp truck engine produces more torque than your car engine, which is then multiplied by gearing.

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KenSee
I understand the question, but am not sure I have any of the answer. I have thought about this as I have a "5hp." Yardman "Sno Bird" snowblower, 2 stage. It seems like it works better than later models of higher nominal horsepower. The most likely scenario, in my mind, is MARKETING, i.e., the mfr. overstating the hp. rating on the newer machines I am familiar with. But that wouldn't be honest.... You could compare the bore and stroke (as well as total displacement) b/w the two engines. The one with the longer stroke (in proportion to the bore size) will produce more "torque," which IMHO ends up feeling a lot like "power," to the operator. Curious if the 12 has a longer stroke-to-bore ratio than the 15hp. In cars, strokes got shorter, until they were "oversquare," i.e., the bore was bigger than the stroke. I believe the Ford 300 I-6 was still "undersquare" when it was last produced in 1996, and it definitely has more torque than at least some years of the 302 V-8. Something to consider....

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Dutch
Peter, You're absolutely right about the 300 six cylinder. I ran quite a few in F-350 tow trucks. They would pull circles around 302 and 400 V8s. However, top speed loaded was "only" 65mph (10mph over the speed limit). Fast enough for my drivers.

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Dutch
I thank you fellas for the replies, it makes a person (me) wonder how a manufacturer chooses what engines to use, with marketing in mind, as bigsix mentioned above, I wonder if in the drawing room when a product is being developed if they consider who, will need a tractor this big/small, and how it would be used and what they base the decisions on??? Im glad to hear I wasnt imagining things...thank you "panel of experts". wouldnt it be great if there was a group of folks that could answer every question a person had (all subjects)

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Dutch
Doesn't make me wonder how some manufactures make decisions..... What sells.....................? BIG horsepower - YES! FAT tires - YES! FANCY paint - YES! HYPE - YES! It's not just garden tractors. What appeals to the crowd with money? Younger, healthier, sexier, faster, easier...... anything they want, someone will offer. BTW - This IS the group that seems to be able to answer any question (at least opine) on any topic. Just ask us.........

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Guest
Man Herb did you just open a can of worms! ANY question? why do so many people like brussel sprouts when they have such a bitter taste? Actually, Spyder, the tech stuff blows me away, I wish i had a brain that could process that stuff but I do find it fascinating, let me give an example. I went to the marine museum in Duluth Minnesota last fall, there is a display that focuses on the engines of the early (1900s) ships and tugs ect. Althoug probably crude compared with todays stuff, I was amazed that these giant contraptions with open connecting rods and copper tubing and brass manifolds worked at all. Some were over 10 feet tall! I WONDERED how they engineered this stuff, trial and error? It seems to me, so much of the what we know today is based on things in the past, but yet these guys had no modles to base there stuff on, ya know what i mean? They would have been shocked if they could see into the future and look at the blueprints for a 12 hp kohler which btw could power a ship! Thats it,I gotta get back to work. thanks again for the info Dougm (Iwonderboy)

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HubbardRA
Difference in horsepower! Older flatheads had massive torque at lower RPMs but did not breathe well at the higher speeds. The newer overhead valve engines are smaller, but breathe better. They have less low rpm power, but make power at higher rpm. Since horsepower on most engines is rated at 3600 rpm and Horsepower is basically torque x RPM. The manufacturers are telling you only what they have "wide open". In fact many mew machines are recommended to be run that way. At 1500 to 2500 rpm, the older engines really do have more power. Nobody is imagining this Rod H.

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Spyder
Hi Doug, I'm going to pull on some of my engineering background, so bear with me. Sounds like you have a significant difference in "drawbar horsepower" versus "rated engine horsepower". 10 HP is not 10 HP. Engines have a power curve which is a plot of engine rpm and torque (measured in foot-lbs). A force of one pound exerted on a moment arm of one foot length equals one ft-lb. The power the engine develops is usually not at full speed. For the Briggs&Stratton 243400 series maximum torque is at 2600 rpm. Engine manufacturers also try to state the "rated engine horsepower" as the normal long term rating to get good engine life. Drawbar horsepower is the pulling power that the engine can produce in a moving machine. Drawbar horsepower also increases with speed. You are not imaging things here. A mathematical model of each tractor could pinpoint the differences, if you are really wanting to find the reason for the observed performance. Download the link below. Its a .pdf file from Iowa State Univ. that will take a while to open. You will need Acrobat reader if you dont have it. Its free all over the web. It is the best explanation I have seen anywhere. Hope this helps. Note: horsepower is a relative measure, not an absolute measure as it has no units. (Only defined by James Watt’s assumption that a horse could move 33,000 pounds one foot in one minute. Dave [A href='http://www.ae.iastate.edu/AST358/Lecture07.pdf']http://www.ae.iastate.edu/AST358/Lecture07.pdf[/a]

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Dadsy98
I would recommend for general reading... "Audel's New Automobile Guide" This is for" Mechanics, Operators and Servicemen with Questions & Answers and Illustrations Written by Frank D. Graham, first copyright 1938 Over 1600 pages of history concerning design and maintenance of the gasoline engine. Steve

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