In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Looking to get a saw to limb with

Discussion in 'Chainsaws and Power Equipment' started by old iron, Nov 30, 2023.

  1. huskihl

    huskihl

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    Cutting speed increases are different than dyno power increases though. The two numbers might be close together but they might be quite aways apart in how they feel. It is easy to raise the exhaust way up and get 7 HP out of 346, but they don’t like cutting wood bigger than 4” without falling off the pipe either
     
  2. The Wood Wolverine

    The Wood Wolverine

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    Here's a plot for a MasterMind261. A tick above 5hp. :dex:
    mmws261.jpg
     
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  3. Eggshooterist

    Eggshooterist

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    In a recent video of Joe's he discovered that very thing. He relied solely on dyno runs for his saw fest builds and got his but handed to him on all but one class if I recall correctly. He basically has started testing in the wood now because of it.


     
  4. T.Jeff Veal

    T.Jeff Veal

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    Have you bought it yet?
     
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  5. huskihl

    huskihl

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    He discovered it quite a while ago because he and I were talking about it before he was even charging to do dyno runs. If a saw has 5HP and gains 50% in HP, it’s now 7.5 HP. If a ported saw gains 50% in cut speed, that is twice as fast as it was stock. So the numbers don’t directly correlate with each other
     
  6. MasterMech

    MasterMech The Mechanical Moderator

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    Dyno info should still be useful though if you pay attention to the torque generated within the normal operating range of the saw. Outside of swapping sprockets, torque can only be manipulated by increasing cylinder pressure or using a larger piston. Stroking the crank or offsetting the piston/cylinder works too but that's not really within the realm of most "woods ported" saws. As long as you can keep the load under the peak amount of torque available, 7HP is 7HP. But that's the kicker isn't it? Torque matters more than HP because for any given size log, it requires a fixed amount of force (torque) to drag the chain through it. If there's more torque available in reserve, the engine accelerates until the torque curve falls off, equalizing with the load.

    Using the 7HP 346 as an example, if we were to gear it down (gear drive saw anyone?) so that the final torque output (match the chain speed?) was similar to a 90cc saw, we'd be cutting 36"+ wood no problem with that 7HP 45cc engine. It would just be heavy, and not last nearly as long as a stock 90cc saw exerting the same amount of force (torque) at a lower crankshaft RPM.
     
  7. Eggshooterist

    Eggshooterist

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    Ahh.. makes sense to me.
     
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  8. Eggshooterist

    Eggshooterist

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    No. I'm showing restraint. For now. Lol
     
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  9. MasterMech

    MasterMech The Mechanical Moderator

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    I still love mine. Don't get to run it enough. But I'd still have a hard time letting it go. I'd sell the 441 first and that thing is excellent too.
     
  10. huskihl

    huskihl

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    One would have to dyno and cut in small wood and large wood with the same saw and recipe several times to get a feel for which one felt better and cut faster. The width of the curve makes a difference in the torque number as well. There is also something to do with the angle of the torque curve at maximum hp rpm. A saw can still cut well if the RPMs are dropping out of the hp curve if torque is still on the rise
     
  11. Deererainman

    Deererainman

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    :rootintootin: :dancer: I love all this sexy talk about RPMS and Torque curves. Am I weird???????????
     
  12. buZZsaw BRAD

    buZZsaw BRAD

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    You and Eggshooterist should start a support group! :rofl: :lol:
     
  13. Eggshooterist

    Eggshooterist

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    First topic will be...

    I have a 241 or two, and you don't, how does that make you feel.
     
  14. buZZsaw BRAD

    buZZsaw BRAD

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    :(
     
  15. The Wood Wolverine

    The Wood Wolverine

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    All my percentage gain remarks/experiences were timed cuts in wood. That’s the first I recall seeing a dyno number gain % shared. Pretty impressive but like you state, most guys here wouldn’t want a piped cookie cutter. :saw:
     
  16. huskihl

    huskihl

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    Yeah I wasn’t referring to your stuff, though I know you’ve done lots of testing . Just trying to show the differences in speed gains vs dyno hp gains to eliminate confusion. The 2 aren’t linear or related
     
  17. JD Guy

    JD Guy

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    Pretty normal in my opinion :rofl: :lol:
     
  18. Deererainman

    Deererainman

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    Same person doing the porting, how does a 346xp compare to the Stihl 241? Similar?
     
  19. huskihl

    huskihl

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    Not similar.
    Ported 346 is rowdy like a big block Chevelle.
    241 is rowdy like a v-8 Vega
     
  20. Deererainman

    Deererainman

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    Thanks for the info.. I like big block Chevelles