If you increase the valve pressure (turn in the screw), you increase the valve's resistance to opening at lower vacuum levels, meaning part throttle or at idle but you also increase the occurrence of compressor surge, which is what a BOV is there to prevent in the first place.
Wonder, Wira 1.6 Auto. This engine did not have o2 sensor for close loop. When tunning, they only allow to adjust the VR,variable resistor ( Lean or Rich ). My question is, how the stock ecu know that the a/f in...