Downshifting
The MAF curve is set to define X amount of airflow per Y Hz of signal. While GM does a substantial amount of research into setting their MAF curve, there is variability in production. Up to a point, the fuel trims can compensate for the MAF being off, but STFT's disable when you go into open loop, and the LTFT's lock into their last value--who knows what AFR you actually get at WOT in this situation.
You really need a wideband and to tune your MAF and VE whenever you make mods that can affect airflow.
The MAF curve is set to define X amount of airflow per Y Hz of signal. While GM does a substantial amount of research into setting their MAF curve, there is variability in production. Up to a point, the fuel trims can compensate for the MAF being off, but STFT's disable when you go into open loop, and the LTFT's lock into their last value--who knows what AFR you actually get at WOT in this situation.
You really need a wideband and to tune your MAF and VE whenever you make mods that can affect airflow.



