datalog at the track - make your test sessions count

[lindermant]

have an SCT device? datalog at the track? add engine RPM, output shaft speed (drive shaft speed - available on 2005+, maybe others), and clutch position (if manual) to your datalog config file.

monitoring RPM loss at launch/between shifts, tire spin (spike in drive shaft speed), and time between shifts (clutch position), along with a good video of your launch will tell the tale...

logged a run last night: blue = engine RPM, purple = driveshaft RPM, gold = clutch position (on/off).

launch, 1-2 shift and 2-3 shift shown below. 12.446 @ 108.80, with 1.675 60' (DA hovered around 2000')

time between launch and clutch in for 1-2 shift = 1.751 seconds (it looks a little skewed because I expanded the x-axis)

 

[stangfreak03GT]

Nice job with the datalog!

So, do you just let your laptop sit in the passenger seat? I've been wanting to do some loging but wasn't sure the best way to do it while going down the track.

 

[lindermant]

Nice job with the datalog!

So, do you just let your laptop sit in the passenger seat? I've been wanting to do some loging but wasn't sure the best way to do it while going down the track.

yea, I bought an OBD-II extension cable so I could tuck it under the dash and run it to the passenger side (otherwise the SCT cable hangs at your feet and is in the way when you shift). car -> SCT device -> laptop.

You can log to the SCT device, and then transfer it to your laptop after the run if you want (but my X3 only holds one datalog file at a time, and if I forget to transfer it gets overwritten the next run).

The SCT Livelink software is a tad clunky. It does not have a function (least not that I found) to set the "O" or launch time. I started the log after the burnout, but before I staged - and there was 28+ seconds of data that I could scrap if I wanted. You can also download the log file as a .csv and then manipulate it in excel, plotly, etc and get rid of that front end data you don't want.