is horse power over-rated?

Discussion in 'Lawn Mowing' started by mike lane lawn care, Jul 5, 2006.

  1. mike lane lawn care

    mike lane lawn care LawnSite Bronze Member
    Messages: 1,707

    ok, so i was wondering, how come an old garden tractor with 8HP have a large towing capacity, and a rear PTO, and my state-of-the-art broadmoor with 20HP is only rated to tow 500 lbs, and has no Rear PTo, and can't tow a grader? is there more to it that just HP, because i was going to put a snow blade on the broadmoor, as it seems heavy enough but i don't want to stress a machine that i use for mowing. so what is the deal with HP?
  2. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Although I think we are on the same track, I always thought it was more like it's UNDER rated LOL. What I mean is, a 15hp Kohler has a lot of power but it sure don't got the strength of no 15 real horses lol.

    But to answer the question, I think back in the days of steel chassis the frame was able to withstand more pull than the lightweight alloys in use today.
  3. Lynden-Jeff

    Lynden-Jeff LawnSite Bronze Member
    Messages: 1,405

    I really debated the horsepower thing when I bought my ZTR. Ill tell ya I had my heart set on a 23-25 HP kawi and at the last minute the dealer talked me in to a 19. IMO I'm glad I went with the 19, better gas mileage, no problems with power (I cut a field that was a good 12-15 inches and it only bogged under extreme piles of clippings), and by law in Ontario I do not need a rops for anything under 20 HP. If I wanted real power I would go diesel!

  4. TriCountyLawn

    TriCountyLawn LawnSite Bronze Member
    Messages: 1,517

    IMO ,I dont think you can have enough HP on a mower. We mow in wet conditions ALOT and the extra HP goes a long way. When mulching you I dont think you could have enough.
  5. Palmer'sLS

    Palmer'sLS LawnSite Senior Member
    Messages: 535

    well i think that these hp rated motors are a joke.....i was talkin to a mechanic at my dealer the other day, and he told me that the difference between the 19,21,23,25 hp kawis was just a simple carb. setting...(this was discussed on an earlier thread i believe), anyways...and im with topsites, there is no way my 19 kawi is givin me the power of 19 REAL horses
  6. tomo

    tomo LawnSite Senior Member
    Messages: 660

    hello, limiting factor for towing maybe 1/chassis 2/ drivetrain 3/engine hp or cooling 4/braking capabilities-------any or all of the above. Engine hp is measured in at least 3 different ways world wide.Then you have different catergories gross hp, intermitant hp , constant hp . After all this b/s you have marketing spin. It can get real confusing at times!!!! Eg if you compare diahatsu diesel .950cc claimed exmark 26.5/toro 27hp and kubota .902cc claimed 23hp on the same graphs there would be lucky to be 1hp diff, both in the 23-24 range under same test criteria.Referance from kub and diahatsu web sites. Do not beleive every thing you are told!! Finally you have different hp spec of the same engine,when hp is actually inreased eg cams carb etc does not typically happen but it is out there.Usally only for marketing purposes"my engine is 1 hp bigger than yours"Give me 1.1 ltrs 28hp kub in a toro ztr now we are cooking*** TOMO
  7. Nosmo

    Nosmo LawnSite Bronze Member
    Messages: 1,216

    I believe him -- according to Kawasaki's power curve chart
    my 23 HP Kawasaki develops 22 HP at 3200 RPM. When set to 3650 RPM it develops 23 HP.

  8. Richard Martin

    Richard Martin LawnSite Fanatic
    Messages: 14,699

    And if you were to continue the curve up the scale the HP would continue to increase. The Kawi dyno chart only shows power where the engine is rated to run at, not maximum power.

    The numbers everybody should be looking at are the torque figures. Horsepower and Torque are inseperable. You can't have one without the other but they do two different jobs.

    Torque is torsional or twisting force. It is the force that propels the mower up a hill or turns the blades. The more torque you have the more weight you can pull up the hill or the thicker the grass you can cut.

    Horsepower is how fast torque can pull the weight up the hill.
  9. Liquidfast

    Liquidfast LawnSite Senior Member
    from Ontario
    Messages: 739

    I took apart my mower once and found what I believe was a piece of a horseshoe. SO.....I know for sure and without a doubt that my mower has ONLY 1 horsepower :realmad: .... I paid for ALOT more than that!
  10. Picky1

    Picky1 LawnSite Member
    Messages: 38

    My 22hp 60" cut Dixie Chopper bogs in tall Bahia. Would I go for more HP? You bet!

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