I wonder if the 2.0sc TB dosent open proportionally to the throtle pedal? Perhaps as its from a charged engine the throtle body movement is not linea to the pedal position. Ie, 25% on the peddel would only give 20% throttle. This might make sense because when under boost, a small change in throttle apature would give a reletivly large increase in air volume through to the engine when compared to a Na engine. If you want to keep the output of the engine fairly linea to the peddel you would have to restrict or dampen the TB opening at the lower end of the scale, gradually increasing its responce to the peddel as you near full throttle. i.e.
10% peddel = 6% throttle
20% Peddel = 11% throttle
30% Peddel = 20% throttle
40% peddel = 30% throttle
50% Peddel = 40% throttle
60% Peddel = 55% throttle
70% peddel = 66% throttle
80% peddel = 77% throttle
90% peddel = 88% throttle
100% peddel = 100% throttle
You get the idea...
If this is so, it would keep the flow rate down under part throttle on our z22se similar to that of the standard 2.2TB and prevent the EML which occurs with the 2.4l TB under the same circumstances, and yet allow greater flow when nearer full throttle which dosent seem to cause any faults on tests with the 2.4TB? As the 2.4l TB is off a NA engine, its responce is probably far more linea and allows to much air under partial throttle for our ECU to accept.