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Topic: Bike interface OBD (Read 146818 times) previous topic - next topic


Hello again. A quick update.

I've gone out and logged some data in a bunch of gears with my Racechrono setup. The purpose was to test 1) OBD Speed vs Speedometer vs GPS as well as to check 2) Oil Temp on cluster vs OBD and 3) Indicated Gear vs Gear from OBD, 4) RPM on cluster vs OBD Log and 5) throttle position values

Here are my findings:

1) The Speedometer always indicates high. For instance, at 120km/h the logged GPS and OBD are at 111 and 112 respectively. I did some research and it's very common for the speedometer to indicate wrong as the MFR's do it on purpose. So I'm happy with the formula kph = byte x 2

2) The Oil Temp is either bang on or 1 deg F off, so I'm very happy with the formula = (byte*160/255)-30

3) The indicated Gear is great. It does a weird value switch at times for instance showing 1,3,5,4,3,2 as gear in the spreadsheet when shifting from 1 to 2. But this is extremely quick and the value settles appropriately at gear 2 within a fraction of a second.

4) The RPM equation seems to be off by and average of 210. The cluster is not digital so the visual readings are very possibly off be 100-200, however, I am positive that they are off. At higher speeds it appeared to be approx 340 off. TriB, I know you're still looking into RPM and if you have any thoughts I'd be interested. The equation I'm using is:

= (byte(H)*255+byte(L))/255*100

5) The values for throttle I did not specifically check, however, I will be doing some comparisons later. OBD apparently usually shows 20-80% for throttle so I'm not sure what the equations range will show but I can determine that later. Racechrono has a great option for percentages and it can scale it. So as long as I hit 100% throttle and 0% then it will scale all the values appropriately in my video overlays.

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