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doesn't the ecu sense load via the output voltage from the hot wire mass air flow meter?
the factory ecu measures the air entering the engine, not the boost pressure, the map sensor is only used for boost cut purposes, so the load axis is actually cfm not psi. the problems you mentioned occur because the airflow exceeds the maximum allowable cfm which the ecu is tuned for. (afm voltage goes out of range) and as a result the ecu can no longer calculate the engines fuel requirements, as a result it either makes it excessively rich (safety feature when excessive airflow is detected the ecu dumps massive amounts of fuel in to avoid detonation) or excessively lean (fuel system cannot flow the required fuel)depending on how far the boost is raised. The heat in the stock intercooler due to raised boost pressure can also lead to detonation.
90% of ebc related engine failures is a result of the owner setting a boost target to high (owners often creep the pressure up a little bit at a time over a few weeks or months and then they get a batch of bad fuel or a hot day and things go bang) or using inferior fuel with the raised boost pressure but not owning up to their own stupidity and using the good old excuse of "it just blew up, i didnt do anything out of the ordinary."
i have set up many ebcs on wrxs which run max pressure of 16.8psi from 3200rpm, and tell the owner they have to use BP Ultimate (98 Octane pump gas) and things run fine. The factory boost cut at 17psi is there for a good reason, the ecu only meters airflow a small amount above this.
if it was possible to setup a someones ebc and pull all the adjusting knobs off so they couldnt fiddle with things many more engines would survive.
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