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lostsoul

Wheel Speed Calibration

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I must be missing something ....  according to "help" to calibrate ..... # of Teeth (26) / wheel diameter (0.61m including tyre ) x 31.83 = 1,334.1 ... to me this can't be right as I am getting a speed reading in the "thousands" kph with a calibration of 260 ??????

Car is a z32 300zx with the G4+ Thunder fitted ... factory wheel sensors.

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The calibration number of ~1300 should be correct for your setup.  A bigger calibration number will give you a lower displayed speed.  I suspect MagicMike's number might be from a gearbox sensor, not a ABS sensor?

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Thanks for clearing that up. What through me was the help section stating that the values would typically be 170 - 280 ... since my wheel sizes are typical and the ABS sensor wheels are factory ... well anyway you get the picture.

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No, the Xtreme DI's are limited to 500Hz.  common ABS rings with more than about 20 teeth will be too many for these.  If you dont need ABS then you can grind some teeth off to make them work.

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Any number of frequency dividers can be used to reduce ABS or high frequency gearbox sensors down to sub 500Hz levels. Dakota digital make a simple to use box that does this, but you can also build your own out of about $15 of parts from jaycar using a 4024 frequency divider chip (I have one on a modern honda gearbox reducing it by /16). If you put this divider between the point you splice into the wire and the ecu, you can leave the ABS in tact.

FYI I also found in testing that the DI inputs can accept slightly higher than 500Hz - about 1300Hz (@12v) they go from reading ok to just reading 0hz until a few seconds after you bring the frequency back down. I wouldn't recommend using them like this though on purpose as i'm sure there is a reason Link dont recommend over 500Hz, but if you hit 501Hz briefly it will still register correctly.

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