The indicated pressure evolution of  the optimised engines (blue and red lines) leads firstly to much higher depression during overlap (near to 0°CA), causing a better scavenging of the residual gases and stronger excitation of the intake pulse, and secondly to a much lower back pressure during the exhaust stroke (between 540 and 720 °CA).

The above mentioned improved indicated pressure behaviour leads finally to higher filling rates (area beneath the mass flow rate line) in the cases of the optimised engines.