The R35 GT-R's turbo control system and monitoring is different than most turbocharged cars. Most cars if they are single or twin turbocharged have a common plenum that feeds all the engines cylinders. The individual cylinders draw on this common plenum for their air. On the R35 GT-R, the two systems are completely separate. One bank feeds one set of three cylinders, the other turbo feeds the other three cylinders.
On the VR38DETTT there is also a manifold absolute pressure sensor, but it seems to be only used to drive a gage. This is how the RB26DETT was also setup in the R32,R33, and R34. On the earlier cars there is no way for the ECU to see the actual manifold pressure, as it uses a mass air flow meter to measure the amount of air coming into the engine, not the pressure of the manifold. The VR38 has two pressure sensors that are used to measure boost and provide feedback for the wastegate solenoids. VR38DETT Turbo Diagram
VR38DETT Turbo Diagram