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Old 10-30-2011, 09:46 PM   #24 (permalink)
3-Wheeler
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AlienMobile - '00 Honda Insight
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Quote:
Originally Posted by MetroMPG View Post
Not commenting on the info as shown, but I was thinking recently about using this method (video of the speedometer) to compare aero mods and had this thought:

1) Switch the display to KM/H (for higher resolution), or,

2) If you have a ScanGauge, switch to KM/H and then change the speed correction factor to increase resolution even further. I'm not sure if it will let you *double* speed, but that would be cool & useful.
Hi Metro,

I have heard from members of the IC forum that the VSS (speedometer) signal gets five pulses per tire revolution on the digital speedometer of the Insight, so switching to KM/H should show an increase in velocity accuracy.

However, I still get quite the variation in seconds for each drop in 1.0 mph decrements during the coast-downs. The graph below shows the variation in the change in seconds per mile-per-hour drop.

The graph below is very typical of the variation I see for each run. The X-axis is mph and the Y-axis is the change in seconds per mph drop.

In the graph above, I have done quite a bit of smoothing using a custom software program to filter this wide variation.

Now the question is, what is the cause of this wide variation?



Jim.
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Last edited by 3-Wheeler; 10-30-2011 at 09:56 PM..
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