What should be disabled/deactived when speed density tuning $EE?

[johnny_b]

I know the obvious ones like setting speed density enable and maf codes.

But my question is what other things like the EGR system and DFCO? Spark modifiers?
and would these things be the same for tuning speed density via fuel trims vs. WBO2?

[steveo]

ve and maf are both methods of airflow estimation.

a maf measures it directly using heated wires, attempting to estimate incoming air, and sending a direct signal to the ECM. the ECM scales this raw measurement using a maf calibration table.

speed density measures it using a pre-programmed table of values of manifold vacuum and rpm, the VE (volumetric efficiency) table.

your ecm then uses the estimated airflow in all its various calculations.

none of the differences between speed density and maf would affect egr, dfco, spark, or whatever (not in a direct way, anyway)

if you tune your VE table properly, most other calculations should behave like they did with a MAF.