Air Supply - N16: Notes

The 4-cylinder N12/N16 gasoline engine is a naturally aspirated engine with Valvetronic (see also VALVETRONIC ).

The intake strokes of the pistons create periodic pressure waves in the intake pipe. These pressure waves travel along the inlet pipe and are reflected by the closed inlet valves. The fact that the length of the intake pipe is precisely geared to the timing of the valves has the following effect:

shortly before the inlet valve closes, a pressure peak of the reflected air wave reaches the inlet valve. This has a supercharging effect which pumps a higher proportion of fresh air into the cylinder.