[Yoshimura]

How the ECU can properly calculate the fuel requirement in open-loop (when using the MAP sensor) if the the MAP sensors values are spoofed (and are thus not the actual values)?

[George @ BMS]

The AFR tables are load based. At a certain rpm pre max boost its on the max in the chart regardless so going higher with boost does not necessarily mean the ECU will run richer. The newer ECU's also look at exhaust gas temperature so it can adjust AFR far richer than the primary tables to keep the cylinder temperatures at bay. The newer ECU's have evolved quite a bit allowing piggy back use to be far more efficient than in the past.