Very dependant upon the tune. Up until a certain point, the ECU is in whats known as "closed Loop" operation and fighting for a stoich 14.7 AFR under idle and most cruise states. The final AFR target in full load will vary depending if your car is stock, on a shelf map or pro-tuned, as well as many other factors. As you apply more load ( increasing boost) , the vehicle will start adding more and more fuel and you will see your AF reading drop lower and lower until you hit your target load and target AFR.
I'm talking about OL, when you hit the gas pedal and start to go up with the boost the fuel by the OL map fuel start to go down, now my question is if the fuel should hit the 11/11.2 from the low 2,3 psi ,or you should drop it moderately during the 14,13,12 till the 11at high boost.
I'm with 3" turbo back catless, AF inbox, sti tmic. Street tune myself.
@moshe_levy Depends on some factors within the tune itself. The O.L table targets are indeed in a descending order to lower as boost goes up, but you also have to take into account other compensation tables such as tip-in enrichment, which help assist port injected motors with a "burst" of fuel that is a little more aggressive than your normal transition for instances when you go and floor it and the throttle butterfly is opening rather quickly, versus slowly rolling into the throttle gently. Generally with the tip-in engaging upon a quick throttle hit, youll see AFRs scoot down low (how low depends on how its tuned) briefly before coming up and then descending again as load builds.
Posted Below is an OEM open loop table from a 2005 Forester XT. I figured a little visual aid here would help you understand the concept better. You have a horizontal (side to side) axis of calculated load which is determined by the MAF sensor and on the Vertical (up and down) axis, its engine RPM. I think its pretty self explanatory with more commanded fuel for more load.