VCDS Parameters/Logging

Hey guys…

So… I searched but didn’t really find this - apologies if this has been covered already.

For Timing :
I see a couple of different parameter sets here that appear to behave differently.
“Ignition angle; actual” and
“Ignition timing adjustment cylinder [1-6]”

From looking at a few logs - the former seems to be the request from the ECU, and would be reduced by the relevant IGA_AD_1_KNK[0-5], but the latter is the direct measurement of the timing for that cylinder? If so “Acutal” isn’t really actual - it’s a request that is dropped by the knock sensors on a cyl-by-cyl basis?

For manifold pressure :
From the schematics I’ve seen - we have a combined temperature/pressure sensor just below the intercoolers on the outboard/front side of each bank ("Charge air pressure sensor 1/2 - G31/G447) but there is also a pressure sensor “Manifold absolute pressure sensor G71” it looks like above the intercoolers just after the charger output. So when you look at “Intake manifold pressure; absolute” that is the value of the G71 sensor? Can you log the G31/G447 sensors directly as well?

Intake Air Temperature :
Same as the pressure - the sensors below the IC’s are G72/G430 and the one before the IC’s (just after charger output) is G42. “Intake air temperature” when logged in VCDS gives the G42 value? Can you log the ones after the IC’s as well? Seems like the logs I’ve seen that “Intake air temperature” is post-cooler since the cars with an upgraded cooling system seem to do better than those without however - maybe this is an average of the 2 post-IC temp sensors?

Air/Fuel ratio :
“Current of oxygen sensor bank 1 sensor 1 (broadband sensor)” reports a lambda that is around 1.000 - if you want true A/F ratios can you just multiply by 14.7, or is there a better way to measure A/F ratio?

Ultimately I’d like to find VCDS channels to log (if available) :

  • intake air temp at 4 points. 1) pre charger, 2) post charger, 3&4 - left/right banks after the IC’s.
  • IC circuit coolant temps - 1&2) pre left/right bank IC 3&4) post left/right bank IC, 5) pre heat exchanger, 6) post heat exchanger.

Any hints?

Thanks…