Algorithmic gear calculation is not going well. Does the ECU output a current gear and if so does anyone know where I can pick it up?

As far as I know the ECU doesn't output the current gear, gear will normally be calculated by a combination of engine revs and speed IIRR.

What gear indicator have you got?

Rich.

It is in a datalogger and the calculation is not going too well so far. Was hoping to cheat and pull the actual gear!

sorry, no, there is a speed pick up from the gearbox though, are you using this output or your own ?

Are you trying to do it live or on recorded data?

Jon, I am using the ECU RPM signal. That looks to be working fine. Final drive is about 3 times so I will plug that in and see how I go.

Chris, currently recorded but will be putting in a dash so will need to be real time soon.

If your raw data is good this should be pretty easy - however you need to handle the periods when the clutch is slipping or disengaged.

Post up some of your data...

I am nearly there and I will post up some of the data. I don't have the car with me at the moment but am doing the following calculation and assuming standard sprockets.

RPM/gear ratio/primary reduction/final reduction*tyre circumference (m)*60/1000=speed (kph)

Have I screwed it up? The gear trace looks roughly right but you can see the effect of a blip about 1/3 of the way through the lap.
Rescued attachment data log.JPG

Can't see your timebase on the plot, how long is the 'blip'? Perhaps you could only register a new gear once it has been in that gear for a short period of time just longer than the clutch is slipping?

The blip last for about 1 second. The total lap was 1min 20s.

It is hard to see but it is obviously speed, RPM, Gear on the plot.

[Edited on 20/3/06 by jecuk]