HP is HP......

Discussion in 'Motorized Bicycle General Discussion' started by scotto-, Aug 25, 2011.

  1. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    No matter how you look at it, horsepower is horsepower. RPM's are one thing, but how you get the power to the ground is what we strive for when racing.

    Brake horsepower on the dynomometer is the true measure of muscle that an engine puts out. Wankle, diesel, 2-stroke, 4-stroke, steam, electric, atomic, turbine, whatever.......it's all about the HP that really gets you moving, or is it?
     
  2. bairdco

    bairdco a guy who makes cool bikes

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    i have an HP laptop and it's slow as ****.
     
  3. happyvalley

    happyvalley New Member

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    A horse can be of a different feather but if you lead a horticulture you still can't make her think.
     
  4. Al.Fisherman

    Al.Fisherman New Member

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    HP is not the true factor. I can mount a 12HP engine on say a go-cart and it won't go as fast as a 2.5 HP. Depends on the gearing also.

    Now that was funnier then "****"
     
    #4 Al.Fisherman, Aug 25, 2011
    Last edited: Aug 25, 2011
  5. rustycase

    rustycase Gutter Rider

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    simple way we used to explain to clients was, "Torque gets you up to speed, Horsepower keeps you motivating." it worked well enough.

    rc
     
  6. mapbike

    mapbike Active Member

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    Good one Baird, I think my Dell must be kinfolks with your HP.....LOL!


    First let me say I'm NOT a pro at this stuff, but I do have some experience building engines stock and modified.


    HP is good but HP alone isn't what gets you moving, it's more about the torque produced by an engine that gets things moving rather than just HP.

    Example: A 3.5HP Briggs engine on a mini bike with a centrifical clutch that has 10T driving a 60T sprocket mounted to a 13" wheel/tire, this set up will take off and go pretty good even with a 200lb fella on it and will hit around 30MPH ungoverned.

    Now take one of those 4.2HP 2 smoker GP460 or a 4HP modified CAG and put it on that same mini bike set up the same way and you will find that you will not be going anywhere fast, do they have the HP rating yes, do they have the torque? NO

    The briggs developes it's HP rating @ around 3600 RPM's and the GP460 or Cag gets it rating at probably 3 times that.

    I said all this to say nope HP isnt all it takes.

    Peace, map
     
  7. James912

    James912 Member

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    Thats a very, very good joke. lol
     
  8. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Yeah, my HP desktop ain't all that fast, but it's pretty powerful! laff

    Afterall.....HP is HP rotfl

    dnut
     
  9. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    HP, Torque, and gears are nothing without control :) (c)
     
  10. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    That's the problem....I'm a little outta control :D

    dnut
     
  11. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    I have never encountered a situation, nor had reason to believe I did not have full faith in any vessel I commanded. Capt. E.J. Smith RMS Titanic
     
  12. mapbike

    mapbike Active Member

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    Thanks for this post scotto, we're having a bit of fun with this, I read and I smile, I like it!

    Peace, map
     
  13. Allen_Wrench

    Allen_Wrench Resident Mad Scientist

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    You need torque to move in the first place. You need horsepower to move the mass faster. But you know what's really fun? - Power-to-Weight ratio! That's what makes a bicycle with a pulse jet strapped onto it such a SICK machine!
     
  14. MEASURE TWICE

    MEASURE TWICE Well-Known Member

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    ========================

    From: Measure Twice

    I have an old 70's era Briggs model type 808202 0430 and I am not sure of the HP or Brake HP (Torque) or even the displacement. But it looks like the size of a similar 3hp more modern Briggs by size I figure. See 3 pics and one with a side by side of my old Briggs and a new one that on an edger the store listed as 3 Horsepower, but Briggs Mfr does only list on the engine as 148CC and 4.75 Foot Pounds of Torque SAE. Also the pic early on of the sort of dropping the engine in for mock up.... still finishing the off road bike now... no pedals.... looking to get State approved OHV sticker for State, Federal, and Private parks that have OHV facilities.

    Just as a word of caution, but I guess many already know is as the engine displacement goes up the power can and does many times does go up and not linearly. That is good though ..... better weight to HP or Brake HP ratio!

    I suppose someone here knows or I contact Briggs directly or go to a shop and see if they have old records for model type numbers to get that info.

    Anyway I saw many times engines that have listed HP at different values maybe as a typo from the seller and differing from the mfr. In any case displacement is probably what I would be looking for to see if the cost for an engine is worth the cost or to make a comparison to another even regardless of cost.

    Then comes the new labeling for small HP Briggs and there are no listing even online for HP, only Torque. I guess no problem there should be a way to convert values. The HP is more of a power rating over a longer period of time and Brake HP (Torque) a more immediate measurement if I think I got it right?

    The reason I read for Briggs to have small, I think somewhere under 10 hp or so listed as Torque and not HP for the power measure was something to do with a more relevant measure for the application that small engines have.

    The thing is that for a long time I always knew about Brake HP (Torque), but really paid no mind to it since I knew of small engine 4 stroke for mini bike and motorized bikes, I was making evaluation of what I saw for this application in HP rating power, and I had apples and apples to compare.

    Now with Torque only to see on new small Briggs engines, I have now apples and oranges, so I guess I can do a conversion to make evaluations work for me. If you know the exact application then if they are the same, then you can try doing an accurate conversion and make a good evaluation.

    I tried a few formulas and had a bit of a difference in them so I have a little bit of a dilemma.

    What is something that I got out of this by serendipity was that I had a couple of engines and think I know more of why the act as they do.
    Beside the many Briggs I have had, were Clinton and Tecumseh engines brand for around 3 to 4 HP ratings. I remember that the later two brands with similar HP rating as it were then, I found pulling the rope starter recoil the feel of the piston to go from compression to power stroke before the engine caught, was a feel that if did not like to stay at top dead center for nearly as long as the Briggs engine.

    It could have been that the Briggs engine was a bit more leaking at the valves and lapping was no longer the answer, the valves and seat needed the angles on both restored by cutting. I did that recently with a few Briggs and it helped a way lot. But if it was true that there was a difference in the piston throw from top dead center to bottom dead center, then maybe I have something here.

    But to the point I heard somewhere that the Clinton engines were very powerful, but what I think what was meant was that it was that they had short piston throw and that equates to more Horsepower for greater speed, but less Torque (Brake Horsepower).

    The opposite with greater Torque and like gearing down the Briggs or any other engine regardless of brand that uses a longer piston throw, up to a point gets more hill climbing ability without gearing down as much comparably. I think of it as a gearing down without the uses of toothed gears. It is mechanical advantage by leverage, no gears though. This maybe not too extreme but does account for maybe the feel in the feel of the rope starter cord pull.

    All this seems that if you desire to climb hills as a trade off with less speed, you might not need to gear down as much later with actual toothed gears or pulleys later to get to the drive wheel.

    Of course if you afford to have a Torque Converter then I guess if you want to go fast and have torque at low speeds, you may I think want an engine with a short piston throw and let the torque converter get the low gear when it finds it is necessary. The infinitely variable transmission!

    Measure Twice
     

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    #14 MEASURE TWICE, Aug 26, 2011
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  15. Pilotgeek

    Pilotgeek New Member

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    Ideally, it should come down to the horsepower. Torque is simply a static measurement. Certainly, you need a good amount of torque to get moving, but once you have adequate torque for the intended load, horsepower becomes what matters. Horsepower is an absolute measure of "power", in the same way as a Watt is a unit of power. In fact, 1hp equals about 746W.

    Torque factors into horsepower, and it's really a matter of Torque x Rpm. Any engine with more horsepower should theoretically be capable of more speed. It's all in how you use that power, by trading torque for rpms in the way you gear it. It's also important to make sure the engines are all using the same definition of horsepower, and you also factor in at what RPM range that horsepower rating is given for, and gearing for that RPM at cruising speed.

    /Idk about you guys, but my HP laptop flies. Then again, I'm not running Windows.
     
    #15 Pilotgeek, Aug 26, 2011
    Last edited: Aug 26, 2011
  16. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    Unless I'm wrong most briggs and other brand motors go by hp @ the out put shaft. 3.5, 6.5 with no load. Any type of device attached to it will reduce H.P. I know Mc Cullah under rates the out put of their motors. Kawasaki, And Kohler does also. (c)
     
  17. Pilotgeek

    Pilotgeek New Member

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    You literally cannot measure horsepower with no load. It's a bull**** measurement then.
     
  18. Arnold Layne

    Arnold Layne New Member

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    HP is a little hard to think about, I usually claim that HP is a measure of the work that can be done in a certain amount of time, and torque is the amount of force it can apply to do that work.
     
  19. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    That power robbing Windows.....Microsoft wants all the power and HP's it can get :D

    dnut
     
  20. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    I'm so sorry I didn't make myself clearer. Bore, stroke,rpms of a said motor are a projection from an engineering stand point. What an engine will make is sometimes way different from Advertised Factory claims. I have seen up to a 4 hp difference in motorcycle motors of the same year and size on a dyno.
     

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