This paper presents a study of the Spark To Piston (STP) concept, engaged in a modern Spark Ignition (SI) 4-valve per cylinder four stroke engine. The combustion stabilization effect from this concept has been utilized in order to increase the engine tolerance to dilution of the fresh air-fuel mixture. It is shown that this tolerance is significantly improved by the STP concept, especially if combined with a high-energy ignition system. Inherent with this improved tolerance comes the ability to reduce fuel consumption and emissions of NOx in a considerable amount. Consequently, STP must therefore be considered a competitive future technique despite its non-conventional approach.