This project aims to enable the reader to acquire the necessary knowledge to fully understand the main facts and working principles of modern wind tunnels and their application in F1. In addition one of the goals is to enable the reader to get an insight of the motorsport world, realizing how important aerodynamics are in relation to the global performance and handling of a race car. Throughout the entire project particular emphasis has been made to illustrate the importance of wind tunnels and how they are necessary even in teams or companies with powerful CFD systems. Despite the fast advances of IT technologies currently every part of high level motorsports aerodynamics cannot be understood without wind tunnels. Starting in an explanation about why the CFD simulation are still not developed enough to be able to be used as the sole aerodynamic design tool in the designing process of an F1 and explaining how CFD and wind tunnels complement each other the project is then divided into two different parts: Part I: The first part focuses in the theory and definitions behind wind tunnel and aerodynamic testing in general. In order to be able to understand the design and characteristics of wind tunnels it is first necessary to describe the aerodynamics principles and their relation to race car designs. All these explanations have been accompanied by real life examples and explained using data measured directly in real race cars. Everything related to wind tunnel testing has been described in this part. Starting from a description of all the different types of tunnels (classified according to different criteria). The main instrumentation required for wind tunnel testing has also been described in this section as well as the differences between scale-model and full size testing with the positive and negative points of each method. An exhaustive listing with the main facts of all the different F1 tunnel facilities has been included, paying special attention to the Epsilon Euskadi headquarters which include the best wind tunnel dedicated to motorsports in the Spanish territory and possibly one of the best worldwide. Together with the Toyota facilities in Germany, they were among the few that were intended to provide the rental of facilities per hour (as a way of self-financing, his topic is extensively dealt with in the economic part of the study). Part II: The second part includes different practical test and experimentations. Firstly based on real track data of a World Series by Renault 3.5 car, an exhaustive study of the DRS systems and its effects in car performance has been carried out. During all the data analysis references to F1 innovations and regulations are made to help the reader immerse into the racing world. In addition the necessary tools and equations necessary to determine the theoretical top speed of any car knowing their characteristics has also been described and applied to the same World Series race car. As mentioned before in this summary during all these sections of the project it has been a priority to give as much real racing information and data as possible trying to give the reader a real experience of the tools race and design engineers use. Without any hesitation the most important part test of the practical part focuses on the World series car rear-view mirrors being tested in different wind tunnel facilities. The aerodynamic study has been realized using different methodologies and tested in different tunnel types. This whole process is extensively detailed in order to enable the reader if desired to be able to carry this same tests (all the necessary tools and calculations included) Lastly, note that this project is not intended under any circumstances to provide numerical values that can be used in real applications as it focuses more on concepts and is intended to be a reference on wind tunnel experimental methodology rather than in the absolute results.