Brand Name & Model of Dyno's

Discussion in 'Harley Davidson Extreme Modification' started by Hoople, Oct 4, 2009.

  1. Hoople

    Hoople Account Removed

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    I am new to the HD world and my experience of dyno's apply to automotive chassis & automotive engine stand dyno's . Would anyone know the Brand & Model of the typical dyno that is used on motorcycles. Since the Most important question I have is if the models used are Inertia (free wheeling drum) or Eddy current (pony brake/water brake) I was hoping to find out what most shops use on bikes.

    I wanted to do some research on measuring techniques and standards in testing & how they compare with automotive standards.

    Tks Hoop!
     
  2. mstngjoe

    mstngjoe Member

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  3. Crocker

    Crocker Active Member

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    Yes the most common Dyno used for motorcycles is made by DYNO-Jet , 200-250i are the most common models used and yes they are eddy current load control. there is one company that I have seen that makes Inertia type dyno I cant remember the name but they are rare ,Dyno-Jet has the main share of the market because they make the most used tuner (Power commander ) So they have good product support and software for there product line .
     
  4. Hoople

    Hoople Account Removed

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    Thanks for the info regarding the Dyno-Jet Brand & models. I am very glad to see that they are load controlled via eddy current. Because of that, they most likely have strain gauge load cell torque arms to measure Torque directly through applied physics instead of a software function. You won't find a better way to calculate Torque and once you have that, the rest is math.

    It's Great to hear that most shops use the same make/model Dyno. It makes for better comparisons from 1 shop to the next.

    Next I will dig up the books on these two models and do some reading.

    Tks!
    Hoop!
     
  5. mstngjoe

    mstngjoe Member

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    The Dynojet 200i is inertia.
     
  6. glider

    glider Veteran Member

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  7. Hoople

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    That's not really what I would have liked to hear. They are Great dyno's (inertia) for comparison work, i.e. I had X amount of horsepower with stock pipes and now I have X+5 horsepower with these SE pipes. The problem is you really don't accurately know what X is. Who ever wrote the software to calculate the values is in charge of what you see... Where as with load cells, they can't and don't lie. Sure you can fudge with "corrected" values, but nothing like you can with a software driven product.

    But none the less, maybe I can find some "loose screws" in the software & things to look out for when doing a dyno pull on one.

    Hoop!
     
  8. mstngjoe

    mstngjoe Member

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    You might want to check out the Mustang Dyno:

    Mustang Dynamometer MDC-325, Motorcycle Dynamometer, Motorcycle Dyno

    SuperFlow also makes a motorcycle dyno.

    If you look at the link I posted above you'll see that the DynoJet was initially based on some "faulty" math.

    Whether or not it has been corrected I don't know. And I also don't know if the motorcycle dynos suffer from the same "condition" as the auto dyno.
     
  9. Hoople

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    Thanks Joe for that info.

    I am sure I am going to get Hammered with hate mail when I say this but an inertia dyno should always be questioned with its results. I am not saying they always lie. But under certain conditions (vehicle weight, drum RPM, factored wind resistance, air density, temperature) they can be very in-accurate. The software really has to be done right and that is very hard to do. All recorded results are software calculated.
    The entire concept of calculating Torque by measuring a change in RPM of a massive rotating drum should be suspect.
    They are Wonderful COMPARISON measuring instruments. But if you want dead accurate numbers, they would not be my choice.

    But I will check them out & ask their tech support some really probing questions!

    Hoop!

    Hoop!
     
  10. mstngjoe

    mstngjoe Member

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    Several years ago I was on a quest similar to yours.

    All of my dyno experience at the time was with small block Ford engines, Mustangs & the SuperFlow chassis dyno.

    The absolute numbers were always secondary to me. I used the dyno for optimizing my tune and sometimes comparison of engine components.

    Although I knew that the DynoJet dynos were showing higher hp/tq numbers across the board, I assumed it was because of the nature of the inertia style dynos.

    Little did I know that Dobeck had fudged the math from the get go.

    You might try contacting Harold Bettes at SuperFlow. A nice guy, easy to talk to. I spent some time emailing him and learned a lot.

    The bottom line: It's a tool. But it needs to be calibrated and run by an honest, experienced professional. Otherwise....it's just bench racin'. ;)