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Woods porting

Discussion in 'Chainsaw' started by alderman, Jul 9, 2013.

  1. alderman

    alderman Addicted to ArboristSite

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    If I were to send a saw to have it ported by somebody in the know, what would I expect to see in return. More power, a bigger power band, which I understand is usable power under more load, or more rpm for a faster cut?
    Can somebody put it in very simple terms for those of us who were never around a shop growing up.
     
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  2. nmurph

    nmurph ArboristSite.com Sponsor

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    In a word, yes.


    You will likely see both in a woods port. Done incorrectly, a WP will produce a peaky, slow to rev saw. But send it to any of the builders with established reps and you will see increases in power and a broad power curve.
     
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  3. bower4311

    bower4311 ArboristSite Operative

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    They can pretty much do anything. The experienced guys will get it as good as possible for working. Correct me if I'm wrong but the general consensus seems to be you can "jump" 10-15cc with a port job compared to a stock saw.
     
  4. treesmith

    treesmith Addicted to ArboristSite

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    On hard Eucalypt today and it was easy, instant throttle response and spool up, power in the cut that makes cutting almost effortless, slightly rich tune as breaking in but it'll be tuned to 14,600 tomorrow with my new tach and then we'll see! It cuts crazy fast already
     
  5. MCW

    MCW Somebody's talking crap here & it ain't the tree!

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    That would be on the mild side.
    For example my pop upped and ported 79cc Dolmar 7900 with a 20" bar is around 20% faster in the cut than a stock 93cc Stihl MS660. Once you get to a longer bar like a 32" buried the Dolmar has only a slight edge, maybe 10% faster.
     
  6. Nitroman

    Nitroman Addicted to ArboristSite

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    It would mean you don't have to buy a larger saw.
     
  7. CJ1

    CJ1 AboristSite Guru

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    Upside as everyone mentioned 20-30% faster and if done correctly better across the board. Bad part louder to extremely loud, more fuel useage and more sensitive to fuel/oil quality. The last 2 are not a big deal to me but a quiet saw is a big plus, fuel is not a concern. Durability? well if you get more HP out of the same parts it would reduce the life of the parts. If there is enough design percentage to handle the extra HP you are good. Most people that I know do not wear out a saw, it either get destroyed or changed out. CJ
     
  8. MCW

    MCW Somebody's talking crap here & it ain't the tree!

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    The other thing to remember though is the amount of wood cut per unit of fuel.
    I've ran the numbers in paid falling and I was well ahead with a ported saw compared with a stock saw. The ported saws use more fuel per time unit but they get more wood on the ground in that time.
     
  9. bower4311

    bower4311 ArboristSite Operative

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    Yeah, I figured it was. So you're 20% faster with 14 less ccs. So that's probably more than 20ccs stock.
     
  10. bower4311

    bower4311 ArboristSite Operative

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    Using that, another way to look at it is like this:

    If you port an engine and modify it for best performance you will lose life on the saw. How much? We don't quite know exactly. But...either way, the saw will still last so long that if you wear out a modified engine, you sure as hell have enough money in your budget for whatever business you're in, to replace the P&C if necessary. Or buy a new saw even. The only downside to porting is cost for someone who is not in the business, for when it's a hobby.
     
  11. treesmith

    treesmith Addicted to ArboristSite

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    My fuel economy doesn't seem to have suffered too much, not that I'd lose any sleep if it did
     
  12. moody

    moody ArboristSite.com Sponsor

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    Ported saws run cooler than stock.
     
  13. blsnelling

    blsnelling Site Sponsor

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    HP makes heat.
     
  14. moody

    moody ArboristSite.com Sponsor

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    Increased flow allows more of that heat escape. Plus the fuel increase allows for better lubrication of moving parts.
     
  15. nmurph

    nmurph ArboristSite.com Sponsor

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    Yep, and though a ported saw pulls more fuel and air through it, it also burns more. Now, if it tuned rich, then you are pulling fuel through that doesn't get burn and it will serve to lubricate and cool the engine some.

    Muffler mods probably do allow a saw to run cooler bc it is allowing the gasses to escape faster regardless of the state of tune.
     
  16. bower4311

    bower4311 ArboristSite Operative

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    There was a thread a while back with an 026 where the temperature was taken at different levels of muffler modding. It got cooler.
     
  17. WhistlePunk99

    WhistlePunk99 ArboristSite Member

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    Depending on the builder the saw can either last or fail. Ignition timing is a critical side to the modifications. The one thing to look at is the carb, port the saw and you need to match the carb to the port job.
     
  18. nmurph

    nmurph ArboristSite.com Sponsor

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    Most saw carbs have enough spare capacity to work well for a woods port. Now for a hot saw, yes, carbs are a very important consideration. And, there are some applications where a carb swap is beneficial in getting that last little bit from a build.
     
  19. blsnelling

    blsnelling Site Sponsor

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    What a woods port entails is ever evolving. It used to mean not much more than widening the ports. It's only in the last couple of years that you could expect significant compression increases, ignition advance, etc. Builders pushing builders makes for a buyers market:clap:
     
  20. moody

    moody ArboristSite.com Sponsor

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    We've evolved into port mapping really. We did this growing up racing Yamaha/Honda products. Our drag Banshee was my first experience with the term port mapping. Takes time and careful thought process but it's worth the gains.
     

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