Many in motorsports are involved in testing “one factor at a time” in order to learn best vehicle set-up. This strategy is a “trial and error” approach and has a very slow learning curve for developing and testing any racecar. Design of Experiments (DOE) is a methodology that can test multiple factors and their interactions. This methodology is a better “trial and learn” approach to better vehicle performance of any racecar. Learning is accelerated by an overall strategy of experimentation using DOE. Application of DOE is demonstrated with data from testing several factors at once for racecar setup in road racing and rallying.