Adding voltage based gear selection indication?

[Chris Wilson]

I have M800 in a RWD Skyline chassis, using a Swedish Tractive sequential gearbox. This came with a display indicating the selected gear on a panel. This is computed from the voltage output of a pot on the selector barrel shaft. Can I ALSO use this output to tell the M800 what gear the transmission is in, and how please?

Given that I can tell the M800 what gear it's in, can I go further and create some sort of table whereby the ecu can log road speed? I don't have any wheel speed sensors, it would need computing from engine RPM, gear selected and diff ratio and tyre rolling circumference. I am going to put the running gear in a new shell soon, and will then have all 4 wheels monitored for speed, and I hope to then add traction control, but for logging purposes right now a road speed and gear indication would be very useful. Thanks.

[dudeman258]

Yes, look under gear detection, and you can use your input value to assign gear for each voltage, it is fairly straight forward. It also allows for provisions to calculate ground speed, you will also need to input your gear ratios and FD.

Let me know if you have any other questions.

Dudeman

[MarkMc]

Wire the sensor into an AV and set it up as a straight 0v=0v, 5v=5v linear calibration for "Gear Sensor Voltage". When you go into the Gear Detection you just need to set the Method as Voltage, the Down Throttle to something like 20 and you want to change the Delay Time to 10, nothing else needs to be set in this screen. Next go to the gear voltages and put the box into each gear with that gear voltage slot highlighted (ECU must be online) and hit enter.

You will need to set a voltage tolerance, this effectively is the length of the dog teeth but in voltage from the barrel position, it is hard to know unless Tractive can tell you but about 50-100mv is a good place to start.

[Chris Wilson]

Thanks Dudeman and Mark, much appreciated, I'll give it a go. Can you see any issue with having both the gear indicator display module [Tractive] and the Motec AV input both off the same barrel position pot?

Also, where would I input tyre revs per mile, or rolling circumference, or whatever, so the data log shows an indication of road speed please?