Torque vs Horsepower

Discussion in 'Lawn Mowing' started by Ursushorribilus, Feb 8, 2004.

  1. Ursushorribilus

    Ursushorribilus LawnSite Member
    Posts: 207

    I've been searching on the subject, and see that torque seems to be more important than horsepower for mowing. A few questions remaining...

    1) What is the relationship between them?

    2) Can machines with lower hp have more torque than those with higher hp?

    3) What brands and models of mowers, specifiaclly the bigger walkbehinds, have the highest torque?

    Being somewhat mechanically unimformed, inexperienced, and possibly incurably inept, I defer and depend on the mechanically inclined and engineers among you. Tony
     
  2. dishboy

    dishboy LawnSite Platinum Member
    from zone 6
    Posts: 4,311

    1. Torque is what sticks you into the seat of your car and horspower is what keeps you there.
    2. Generally horsepower and torque curves are a result of a lot of variables including cam lift\duration, bore & stroke and head design. Most high horsepower engines sacrifice torque in the low and mid rpm's were a mower needs it. The same identical engine with less cam lift will usually have less hp and more torque. Some engines with a really good head design have both, and large displacement engines may have both.
    3. What mowers have the highest torgue? I do not know this.
     
  3. dishboy

    dishboy LawnSite Platinum Member
    from zone 6
    Posts: 4,311

    I errored, the same engine with less cam duration[not lift] will usually have less hp and more torque.
     
  4. MudslinginFX4

    MudslinginFX4 LawnSite Bronze Member
    Posts: 1,170

    For a truck atleast... "Horsepower is what sells the car, torque is what gets it off the lot".
     
  5. olderthandirt

    olderthandirt LawnSite Platinum Member
    from here
    Posts: 4,900





    "Horsepower is what sells the car, CASH is what gets it off the lot".:D

    Mac
     
  6. Albemarle Lawn

    Albemarle Lawn LawnSite Bronze Member
    Posts: 1,544

    Horsepower is a mathematical calculation.

    Torque and RPM's are the input, measurable data pieces, horsepower is just a computation.

    Check out the Randy's Ring and Pinion website, they have some cool calculation tools:

    http://www.ring-pinion.com/calculators/calculatorsind.html


    BTW yes it is torque that is really important. In fact, many engines such as the Kawasaki 25 and Kohler 25 do not actually make a usable 25 Horsepower. The "horsepower" rated is a gross maximum output number. Continuous horsepower for the Kohler 25 is actually closer to 20.

    Something with REAL power, like my JD 1600 wide area mower, can hold a continuous, honest-to-goodness 65 Horsepower, at 3000 RPM's (vs 3600 for gassers).

    Big torque at low RPM's means your motor is making more horsepower at a lower RPM.

    The real advantage comes in heavy, tall grass or on hills. With a torquey diesel your torque actually increases as RPM's drop, which means, realistically, RPM's wont drop much at all.

    My Deere diesel is so strong that it will smoke a belt at half throttle before it will stall the engine if you suddenly find your mower deck in "the thick stuff."


    KB
     
  7. MudslinginFX4

    MudslinginFX4 LawnSite Bronze Member
    Posts: 1,170

    HAHA, your right about that Mac.... and thats the worst part, the cash.
     
  8. dishboy

    dishboy LawnSite Platinum Member
    from zone 6
    Posts: 4,311

    Albemarle Lawn, well said!

    Olderthandirt, I am LMAO!

    Tom
     
  9. Ursushorribilus

    Ursushorribilus LawnSite Member
    Posts: 207

    Thanks guys, I'm getting the drift, if not understanding the exact technical aspects...I'm going to become a "torque junkie" instead of horsepower.


    Albemarle Lawn, that ring-pinion website is pretty slick, I'll be using their calculator.
    I checked out the John Deere 1600 Turbo Wide Area Mower on their website, what a monster! At $50,699.00, their listed price, I'll be a few years getting one of those :) The applications for one of those must be for really large acreage! What is the fuel consumption for that beast? Tony
     
  10. Albemarle Lawn

    Albemarle Lawn LawnSite Bronze Member
    Posts: 1,544

    My fuel burn has been a consistent 1.1 gallons per hour at full power. For our municipal work where quality of cut is not as important, I set power at about 75% and then I'm at about .9 gallons per hour.

    For comparison, all my ZTR mowers have either the Kawasaki 25 or the Kohler 27. They burn 2.2 gallons per hour.

    So there you have it. Cut 60" at a time with a gasser and burn 2.2 gallons per hour.

    Or, cut 11 feet at a time on LESS THAN HALF THE FUEL...

    Plus, I'm running OFF ROAD diesel, so that drives the cost down even further versus gas.

    One day last summer I really amused myself. On 7 gallons, I cut a 10-acre school, a 20 acre park, and a 9 acre farm. Total revenues = $2400 +/-, total fuel =$9 +/-

    Of course, that was a busy day. Normally we cut $300 of grass for every gallon of fuel on the $50,000 Deere. Every time the tank gets topped off at least another $3000 flows into the coffers.

    Here's the sweet part..."Big Green" is paid for!!!

    Ken

    BTW $50,000 +/- is before the options, such as canopy, turn-breaks, worklight, and a few others. Total replacement on mine is currently $53,900 and don't forget another $2500 for sales tax.
    I get off on telling my customers it cost as much as their 2004 Mercedes E Class or their Ford Explorer, Toyota Camry, and Honda Accord COMBINED!
    :cool:
     

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