The new driving cycles require a greater focus on wider engine operative area and especially in transient conditions where a proper air path control is a challenging task for emission and drivability. In order to achieve this goal, turbocharger speed measurement can give several benefits in boost pressure transient and over-speed prevention, letting the adoption of a smaller turbocharger, that can reduce further the turbo-lag enabling engine downspeeding. Until now, the use of a turbocharger speed sensor was considered expensive and rarely available for passenger cars, while it is used on high performance engines with the aim of maximizing the engine power and torque, mainly in steady state, eroding the safe-margin for turbocharger over-speed. Thanks to the availability of a new cost effective turbocharger speed technology, based on acoustic sensing, the turbocharger speed can be used also for passenger car applications. In this paper, a new model based boost pressure control, using the new measurement, is proposed. The control has been designed and validated by means 1-D model of a small turbocharged Diesel engine for passenger cars. Moreover the achievable benefits have been analyzed.