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data logging and tuning

Posted: Sun Oct 30, 2011 12:52 am
by terrysheldon
I have been data logging and was curious about how to use the knock retard info, on one when im in WOT was -3.0 and another one was +3.0, but the total remained at 0. The max retard was at +12? Is this offset normal? Is one of the knock retard values the main one to be at 0 and the others go up and down? If the positive number from adding time, or is the low one from adding time? I am sure I will be having a custome tune done but I am still wanting to learn more about making adjustments on my own when I need to. Living at 7k elevation is more difficult to have the canned tunes work to their max potential.
Sorry it's a long post really wanting to learn tuning a motor without a screwdriver and timing light. :?:

Thanks for any feed back!

RE: data logging and tuning

Posted: Mon Oct 31, 2011 5:48 pm
by abuelo
The knock retard is how much the comptuer is retarding from the ideal calculated point based on the feedback of the knock sensor. Lets say you get a 3° retard and your actual timming is 12° BTDC (before 0); this means that the timming was 15° but the PCM retarded (made it happen latter) to 12°.
I also live at +7k ft above, and I think the Diablo is not working very well in WOT adjustments at high altitude; this means that the changes should get arround 100 KPa range, but WOT at this altitude would read arround 75 KPa so I thing it is not (or barely) adjusting in this range. I have pending to do a thread about that, but been traveling a lot lately an it will require a bunch of logs and custom tunes to accomplish.....