In this paper, an experimental validation of a constrained Nonlinear Model Predictive Control (NMPC) is shown for a Diesel engine air path. A fast parameterized approach is proposed in order for the resulting control scheme to meet the real-time requirements. The control strategy is completed by a moving horizon observer (MHO) to estimate the unmeasured states. An attractive feature of the proposed control strategy lies in its compatibility with more elaborated and fully nonlinear models since it uses the model as a black box predictor.