by bulwnkl » Fri Jul 11, 2008 1:51 pm
I'd like to bring this thread back to the top because in logging my Baja ('05 turbo A/T) I have encountered the same thing. WGDC maxes at 90.2% (until it starts trimming back above ~5,000 rpm), which resulted in a peak boost pressure of 10.45psig on that day. Interestingly, the theory in the FSM for how (and why) Subaru uses a mechanical wastegate actuator with the BCS on top of it is that:
The wastegate actuator is supposed to set max boost, but the BCS is there to allow higher boost because the ECU is supposed to maintain a certain power (output) level. Thus, at higher elevations like where I live or under other conditions that drop absolute atmospheric pressure, the BCS is there to allow higher-than-target gauge (relative) manifold pressure so that you get zero power loss at (for example) higher elevations. It seems clear, however, that the reality is somewhat different from the stated theory.
In any event, did the OP ever increase restrictor orifice size or anything else to increase boost levels? What was the outcome here?