Originally Posted by Greg in Oz

The multi-position selector with numbered positions and one position marked S and one marked N is R16. This sets the ignition module (EZL) to look-up different ignition timing maps. Position S is used for premium or super grade fuel whereas N is used for lower octane fuel. S is intended as the default setting whereas when travelling into areas with lower grade fuel N can be used with a resultant slight loss of power.