Using OP-COM as a Dyno [Archive] - SaabCentral Forums

: Using OP-COM as a Dyno


Deli-Llama
25th June 2014, 06:06 AM
As the title says, I think I've found a way to use OP-COM to plot engine torque vs engine speed (and therefore power). There is a measuring block on the 5 speed automatic transmission that shows the engine torque. To be fair, I'm not sure how accurate the torque measurement is but it seems fairly accurate based on my initial testing.

Here's a screen shot of what I'm talking about:

https://www.saabcentral.com/forums/attachment.php?attachmentid=96914&stc=1&d=1403688628

Now I've left out the bleedingly obvious steps like connecting the OP-COM cable to your car via the OBD port (and laptop) and starting the engine but here are the steps I used to log the data:

1) Start OP-COM
2) Select "Diagnostics"
3) Select "2008" (for my car)
4) Select "Vectra-C / Signum"
5) Select "Transmission"
6) Select "AF 23-5/33-5/40-6"
7) Select "Measuring Blocks"
8) Select "Diagnostic Data Display 1"
9) Select "Next Block"
10) Select "Record"
11) Enter a filename and click "OK"

Now for the fun part. I switched to "manual" mode and selected 2nd gear then I just mashed the accelerator pedal until 5,500rpm (to ensure I didn't break the speed limit). Yes, the car was stationary before I stopped the recording in OP-COM. So now that I had a CSV file I opened it using Excel and added a graph of the data:

https://www.saabcentral.com/forums/attachment.php?attachmentid=96922&stc=1&d=1403689630

Keep in mind that only engine speed and engine torque are being logged by OP-COM. I used formulas to calculate power (well that's what a dyno does so I didn't see anything wrong with that) and then covert from metric to imperial for those of you that prefer non-SI units.

If anyone has done something similar I'd be keen to hear how accurate you think the engine torque measuring block is.