Dynamic Cylinder Air or Cylinder Air Mass

[boatdoctors]

How is it derived?


Thanks,
Marshall
2002 K2500 6.0 Suburban

[EC_Tune]

Dynamic Cylinder Air is the same as Cylinder Air Mass.

DCA is:
MAF Airflow in g/sec * 15 / RPM for a V8 (*20 for V6 and *30 for I4)

[boatdoctors]

DCA is:
MAF Airflow in g/sec * 15 / RPM for a V8 (*20 for V6 and *30 for I4)

Thanks!! The reason I asked is that my timing is jumping to 0 or negative with no KR. I logged all of the timing PIDs and found the base timing was doing it. And found that when it happens the DCA is jumping from 70 g/cyl to 100 g/cyl in one frame... MAP and MAF and RPM are pretty much flat lines so it makes no since to my why it would jump.

This happens when accellerating in high gear, tcc locked...
I am runing 2 bar OS.

I would post my log and tune, but I am unable to just yet..

[1CAMWNDR]

How do you measure this airflow if you no longer have a MAF?

[redhardsupra]

DCA=GMVE*MAP/TEMP
where GMVE=VOL*VE/R
where VOL is a cylinder displacement, VE is the standard 0-100% volumetric efficiency, and R is a chemical constant for air

[1CAMWNDR]

Ow my brain. Have to make my own PID huh. That should prove to be interesting.
Thank you oh learned one...........

[5_Liter_Eater]

You don't need your own PID, it's already there. Marcin just showed you how it's calculated.

[boatdoctors]

Doh!!! It was P0101 causing the airflow jump...

Thanks for the replies...

[1CAMWNDR]

You don't need your own PID, it's already there. Marcin just showed you how it's calculated.

OK so do I still just use the MAF airflow PID or what??
I am so tune-dunce.

[redhardsupra]

well, it's not that simple. you want the multiple PIDs for Cylinder Air Mass calculated from fuel, from MAF, and from VE table (SD mode). I literally have 4 Cylinder Air Mass' PIDS:
CAM0= Dynamic Cylinder Air, whatever the scanner gives me. useful to see how much smoothing/filtering the ECU does, comparing to the other CAM's
CAM1= 15*MAF/RPM (CAM from MAF)
CAM2= IPW*IFR*AFRwb (CAM from fuel)
CAM3= GMVE*MAP/MAT (CAM from VE table/SD mode)

I highly recommend making PIDS for all these just so you can graph them all at the same time. You will see in what situations (steady vs transitions, low vs high airflow) which CAM is going crazy and when it agrees with the others.

[1CAMWNDR]

OK. What sensors do I select in the list when making this PID for SD CAM(Your CAM3)?

[redhardsupra]

GMVE and ManifoldAirTemp is not supported on all platforms yet, so feel free to bug Chris@HPT

this is the setup you want: