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Most powerful 372XP

Discussion in 'Chainsaw' started by Simonizer, Oct 23, 2007.

  1. Simonizer

    Simonizer Addicted to ArboristSite

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    I just dynoed one at 8.2HP@14160. No expansion chamber. Stock is 5.4. Doug Herman raced it against a modded 390 and won marginally in a 50" spruce, bucking, 34" 75ga. Fun. Cheers, Simon.
     
    Last edited: Oct 23, 2007
  2. SWE#Kipp

    SWE#Kipp Addicted to ArboristSite

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    Thats insane :D
    good work !!!!
     
  3. Simonizer

    Simonizer Addicted to ArboristSite

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    Still 71 cc's, but vented-skirt piston and pretty aggressive porting. I have built about 80 this year, had a half-dozen connecting rod failures, big-end. 3 or so were due to poor quality oil. Doug is a pro-faller and has two of mine both over a year old, both still strong other than usual wear, clutches etc. Is is sad that production on this excellent little machine will stop in 2008. Last year the swedish engineers told me they would be available through 2011, but I guess the emissions criteria folks are really pushing these 575's, (which are a piece of S**t).:mad: :cheers:
     
    Last edited: Oct 23, 2007
  4. Peacock

    Peacock Addicted to ArboristSite

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    Sounds awesome!!

    So you hate the 575.....what's your opinion on the 441? I realize the mod-ability of strato saws is limited.
     
  5. Mr.

    Mr. being watched

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    Do you find 5.4 to be the average for stock 372's when you test?

    Fred
     
  6. jack-the-ripper

    jack-the-ripper AboristSite Guru

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    What type of modding was done to the 390? Also what is the longevity of such a highly modified saw, not typically for everyday use I imagine.
     
  7. PES+

    PES+ Addicted to ArboristSite

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    I had the same question Simon

    Did you dyno the stock 372s on the same dyno as a reference?

    Also what type/brand is the dyno?
    Water brake?
    Electrodynamic?
    Mechanical brake?

    What calibration standard are you using?

    I bet people would love to see some pics of your test set up
     
  8. troutfisher

    troutfisher Addicted to ArboristSite

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    I would like to see that setup! I use the old wood dyno with a stopwatch.
     
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  9. brncreeper

    brncreeper Addicted to ArboristSite

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    Probably Inertia or Hydraulic.
     
  10. Simonizer

    Simonizer Addicted to ArboristSite

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    Actually torsion-bar set-up. A driven shaft is forced against a load, (tiny disc-brake), the shaft deflection is measured at several different rpm's. Horsepower is derived from 2*Pi*rpm*torque/33000. This gives a very accurate reading as there are no frictional losses to calculate as with a hydraulic or electric dynos. Yes, the stock 372 does deliver 5.35 hp +/- 0.30 hp. Any saw builder will agree with me that there are casting differences and port-height differences as Mahle probably has 25-30 different dies. Cheers, Simon.
     
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  11. Dennis Cahoon

    Dennis Cahoon Addicted to ArboristSite

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    Simon, did you mod the 390.....Hahahahahahaha!
     
  12. 2000ssm6

    2000ssm6 Stihl User

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    Do you run any other saws? Looks like you are a Husky man. I would like to see the Stihl and Dolmar numbers.....

    btw that 372 is smokin' :cheers: :cheers:
     
  13. PES+

    PES+ Addicted to ArboristSite

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    A straight mechanical brake dyno

    With no friction losses

    Now I GOTS to see a picture
     
  14. sILlogger

    sILlogger Addicted to ArboristSite

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    so i have to ask...what could u get out of a 395 or a 660???:clap:
     
  15. RiverRat2

    RiverRat2 Addicted to ArboristSite

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    Thats easy!!!!

    How much money do you have????? LOL!!!!!
     
  16. sILlogger

    sILlogger Addicted to ArboristSite

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    yea...i know what u mean...but if he can do that to a 372 then the potential really ought to be there for a 395 or 660 worksaw
     
  17. troutfisher

    troutfisher Addicted to ArboristSite

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    [​IMG]
     
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  18. Simonizer

    Simonizer Addicted to ArboristSite

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    The resistive load is 100%friction, but the torque measured before this gives the accuracy that beats a hydraulic or electrical dyno.
     
  19. PES+

    PES+ Addicted to ArboristSite

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    Simon
    It appears you are reluctant to post a pic of your set up.

    That is fine with me but again I ask what you are using as a base of reference.

    You may either be shorting yourself in actual HP OR you may be using a base calculation that is over estimated by using two different sources of measure.

    You are aware that the KW rating of pretty much all saws is not a direct correlation to HP figures are you not?

    And you should also know why this is.

    No calling out anybody nor bashing or anything of the kind.........

    Let us have a true technical discussion.

    BTW you have so far been extremely fortunate with the crank failures by your posted numbers.
     
  20. rahtreelimbs

    rahtreelimbs A.K.A Rotten Tree Limbs

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    Amoungst My Saws........Fool That Has Too Many!!!

    As it is and always shall be!!!
     

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