On another thought, I wonder what the decision was for placing the TMAP prior to the TB and then needing to utilize an additional sensor in the manifold for vacuum conditions. This must have made the load calculation more difficult. They would have to monitor the vacuum sensor in the manifold until they reach positive pressure at which point they would switch to the TMAP. Well, I guess that simple logic isn't hard but this does add an additional part.
Why not just run a single sensor which reads both vacuum and boost and have it in the manifold where is counts. I guess the resolution is increased by using two smaller range sensors. Plus, the verification of proper pressure release through the diverters is beneficial by having a sensor fore of the TB. But it still seems like a waste of parts and engineering.
Lastly, I have to beleive there is some pressure drop through the TB, exspecially as the flow rates increase. With a closed loop fuel system it would compensate, but wouldn't it be better to be on the mark more often by reading true manifold pressure.
Just tossing out ideas out of curiosity again...
