I require some technical help on the cfd of an fsae intake manifold, regarding specifying the boundary conditions. According to flow simulation, specifying outlet boundary condition mean flow is exiting the manifold to that condition. I don't understand why in case of intake manifold most people and solidworks tutorial has specified environmental pressure(101325Pa) at the outlet of runners, as the flow here enters the engine of the car and not atmosphere. Rather env.pressure should be given at the inlet as the flow is entering through the environment considering ambient conditions. I just want to check the pressure loss till the air reaches the engine. And taking the bc's as provided in tutorial( inlet velocity, outlet env.pressure), solver shows pressure at inlet above the ambient pressure! Please help and provide some technical understanding about this!! (As in cfd of c-d nozzle the selection of boundary conditions is straight forward.) I am not doing time dependent transient analysis, but the simple analysis.

Values for boundary conditions in cfd of c-d nozzle-

inlet env.pressure- 101325Pa

mass flow rate- 0.075kg/s (reference max.)