Page 1 of 17 123411 ... LastLast
Results 1 to 10 of 162
  1. #1
    Member
    Join Date
    Oct 2010
    Posts
    39
    Location
    Australia
    Tractor
    Yanmar EA 2400

    Default Does HP matter?

    If two tractors have identical peak torque but one has more power than the other is there any point in getting the tractor with more horsepower?
    For example the JD 3032E has 31.4 Hp while the JD 3038E has 37 HP but they have identical peak torque.
    Are those extra horses useless?
    I would have thought that for heavy work like rotary cutting thick scrub that the extra horses would not help?


    Mark

  2. #2
    Super Member mjncad's Avatar
    Join Date
    Aug 2006
    Posts
    5,114
    Location
    In the civilized First World
    Tractor
    A couple

    Default Re: Does HP matter?

    Ask a woman if size matters.

    Seriously now, do the peak torque and HP numbers occur at the same RPM's between the engines? If the extra HP's don't cost a lot extra, I'd go with the 37HP unit as it in theory will get you an extra foot of brush-cutter width using the rule-of-thumb of 5HP per 1-foot of brush-cutter width.
    Paraphrasing Douglas Adams - So long and thanks for all the bacon.

  3. #3
    Super Star Member
    Join Date
    Jul 2011
    Posts
    14,436
    Location
    Yanceyville, North Carolina
    Tractor
    Kubota L4400

    Default Re: Does HP matter?

    There is a difference of five-5 HP - PTO in those two models. TractorData.com - information on all makes and models of tractors
    The PUPIL who does not surpass his Master, fails his Master.

  4. #4
    Platinum Member JD 4520's Avatar
    Join Date
    Apr 2011
    Posts
    834
    Location
    Brinnon, WA
    Tractor
    John Deere 4520

    Default

    Get more HP if you can. You won't later regret it.
    Gary

    JD 4520, 400X FEL, Frontier Front Blade, Box Blade, Rotary Cutter, Landscape Rake, 48" Wildkat Grapple and PHD

  5. #5
    Veteran Member KennyG's Avatar
    Join Date
    Jan 2011
    Posts
    1,161
    Location
    SW Michigan
    Tractor
    John Deere 2320

    Default Re: Does HP matter?

    Torque is a measure of force while horsepower is a measure of work done so, yes, higher horsepower is useful. If two engines have the same torque but one has higher horsepower, it means the higher powered one will develop that torque at a higher engine speed and do more work. In the case identified above, different causes could exist, but if both are geared to produce maximum power at the PTO speed, the higher horsepower tractor will put more energy into the driven device and do more work.

    The only case in which this wouldn't work is if both tractors have the same gearing and the higher horsepower tractor only produces the greater horsepower beyond the PTO speed, in which case the extra power can't be used when using a PTO powered implement.

    If you look at tractors, you will find that PTO horsepower is almost always less than engine horsepower. Theres a bit of drivetrain loss but most of that is because the torque curve is very flat and the engine will rev somewhat past the PTO rated speed.

  6. #6
    Elite Member
    Join Date
    Jul 2009
    Posts
    4,299
    Location
    SW WA
    Tractor
    Kubota BX2360

    Default Re: Does HP matter?

    Depends if you are pulling or powering, too.

    A heavier tractor with a smaller engine will often outpull a lighter one with a larger engine. Weight makes traction, horsepower lets you run bigger powered implements or do the work faster.

    Bruce

  7. #7
    R.I.P.
    Join Date
    Dec 2008
    Posts
    5,883
    Location
    North Carolina
    Tractor
    Kubota BX2200

    Default Re: Does HP matter?

    Horsepower is work per unit time. Work/per hour, etc. All things being equal, I'd go for the higher horsepower. But I don't say that lightly. You supplied an important point: the torque is equal. But you didn't say what your travel speed limitations are...so I presume low range low gear will be slow enough for you on both tractors.

    The reason it matters is motors always have to be coordinated with gear box ratios. These modify the torque and the speed, and you'd be surprised how many situations I have walked up on in an industrial environment where folks choose a certain HP first because they have a rule of thumb about how much power a machine will take. Then, they meet with production people who ask for extremely fast speeds so the engineer just changes the gearbox ratio and then purchases the machine. Then in production at normal speeds, the device doesn't have the final torque to run the process, but unloaded it can run fast as heck! It's disheartening when I see that happen, but I doubt it will happen with your tractor choices.
    Which is bigger?: a) $100 per month since the Big Bang or b) the US National Debt.

  8. #8
    Silver Member
    Join Date
    Dec 2010
    Posts
    185
    Location
    Love, VA
    Tractor
    Kubota B7100 HST 4WD

    Default Re: Does HP matter?

    Dollars to donuts the torque peak is at different RPM's between the two engines. HP and torque numbers are only part of the equation; where in the RPM range that they happen is important, too.
    "For I am not ashamed of the gospel of Christ..." Romans 1:16
    Kubota B7100 HST 4WD
    94 Dodge Ram 2500 CTD

  9. #9
    Super Star Member murphy1244's Avatar
    Join Date
    Nov 2011
    Posts
    17,024
    Location
    Ohio
    Tractor
    Kioti DK 40-Massey ferguson 135-Ventrac 4500 Diesel

    Default Re: Does HP matter?

    Quote Originally Posted by hodge View Post
    Dollars to donuts the torque peak is at different RPM's between the two engines. HP and torque numbers are only part of the equation; where in the RPM range that they happen is important, too.
    Good advice, I would take the machine that peaks at a lower RPM assuming same same.
    Murph ------------

  10. #10
    Veteran Member KennyG's Avatar
    Join Date
    Jan 2011
    Posts
    1,161
    Location
    SW Michigan
    Tractor
    John Deere 2320

    Default Re: Does HP matter?

    Quote Originally Posted by murphy1244 View Post
    Good advice, I would take the machine that peaks at a lower RPM assuming same same.
    But the original question was about bushhogging. For that application you would want the machine with the highest PTO horsepower since you will be running at the PTO rated RPM.

Page 1 of 17 123411 ... LastLast

Similar Threads

  1. Will 5 hp more matter ?
    By castiman in forum John Deere Buying/Pricing
    Replies: 21
    Last Post: 02-19-2011, 01:31 PM
  2. It was only a matter of time
    By Diamondpilot in forum Trailers & Transportation
    Replies: 41
    Last Post: 08-04-2008, 06:12 AM
  3. Does size matter?
    By EastTractor in forum Owning/Operating
    Replies: 6
    Last Post: 06-05-2007, 06:33 PM
  4. Does size really matter?
    By Zoombah in forum Attachments
    Replies: 32
    Last Post: 06-12-2006, 12:16 AM
  5. It was only a matter of time.
    By Hillbilly in forum Related Topics
    Replies: 12
    Last Post: 12-05-2001, 05:53 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.