that it was Nissan's intended design objective. The reason the intake manifold is designed the way it was is get the greatest flow and torque in the space consideration with the long straighter intake runners without 180 degree bends in the runners. If Nissan design the intake manifold so that the left feeds left bank and right feeds right bank, the intake runners would have to have tighter bends which would hurt flow and torque. Somebody posted an article on here on how Nissan came to design the intake manifold. They did a lot of testing with air flow and how it affected torque . The short runners and tight bends hurt flow.
