Author Topic: Dynos = yardsticks, not micrometers  (Read 1289 times)

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Online Steve in Sunny Fla

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Dynos = yardsticks, not micrometers
« on: December 29, 2017, 05:26:29 pm »
Here's a great video explaining how the same bike, on the same dyno, can produce different results on different days, and the only way to get a baseline is with a standard. In this case "christine" is the standard. in this manner, you can figure the relative performance of another bike on the same dyno in the same conditions. If you notice, the standard is based on real world performance.

  Kinda shoots big holes in what misconceptions most have when it comes to evaluating and comparing dyno charts, particularly from different dynos.

  watch particularly from the 2 min to the 11:30 mark.

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Offline connie_rider

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Re: Dynos = yardsticks, not micrometers
« Reply #1 on: December 29, 2017, 08:51:04 pm »
Very good video.
I saw the exact differences he's speaking about when I ran the dyno's for Shell.

NOTE: He's particularly bringing up humidity as a factor in the numbers.
               Other things effect the numbers too.
               For instance; I saw very similar changes when the barometric pressure changed during tests..
              {NOTE: On our dyno's we were able to control Temp. and Humidity}.

One thing the video doesn't go into is; dyno testing vs real world riding.
  Most Dyno runs are conducted with the throttle only at WOT.
      {All the plots you see posted are done at WOT}
  These Dyno runs are NOT real world. Because; You do not run WOT most of the time.
      The most important part of tuning is done using data collected on a road, in real world conditions.

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« Last Edit: January 07, 2018, 05:19:15 pm by connie_rider »
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Offline Mcfly

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Re: Dynos = yardsticks, not micrometers
« Reply #2 on: December 30, 2017, 12:42:26 am »
A bit wordy, but a very eye opening explanation.

I have near zero experience with dynos...  the 'butt dyno' has been the only one I've used.

Being in Sunny Muggy Floh-ri-duh, it would be safe to assume you're dyno numbers would
not compare well to say a dyno in New England on most days... add all the 'math' that is calculated by the dyno itself
and the results could probably show a considerable variance.  So I get it more now.

As for me personally... I don't give a hoot about numbers...  I don't race. I care how the bike runs and responds,
and how enjoyable the experience is when I throw my leg over on a Sunday afternoon.   Nice Job.   :great:

Bet meh...  I'm just crazy   :o
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