This overlap occurs between the end of the exhaust stroke and the start of the intake stroke. High performance engines, which are subject to compromising smoothness for extreme power delivery, use high values of this parameter in order to benefit from the pressure waves to improve engine performance by maximising volumetric efficiency. On the Testastretta 11° engine, this angle has been reduced from 41°, used in the Testastretta Evoluzione engine which powers the 1198, to 11°. As a result, the fresh inlet charge flow is less compromised by the exiting exhaust gases, resulting in a much smoother combustion in addition to improved fuel economy and lower exhaust emissions.