Turbocharging is an important part of engine downsizing. Today, the control of the air charge system often consists of single-input single-output systems, where one input controls one output. With the increasing demand of lowering the emissions it is believed that solutions as long route exhaust gas recirculation and multiple stage turbocharging will be introduced for gasoline engines. This adds more actuators to the air charge system making it a multiple-input system. In the paper the implications of turbocharger speed measurement on the boost control system are investigated. A controller with turbo speed measurement, and one controller without is developed and implemented in a turbocharged inline four gasoline engine equipped with an electric servo-actuated wastegate in an engine test bench. The controllers ability to control the boost pressure is then discussed. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.