The Magma engine concept is characterised by a high compression ratio, central injector combustion system employed in a downsized direct-injection gasoline engine. An advanced boosting system and Miller cycle intake-valve closing strategies are used to control combustion knock while maintaining specific performance. A key feature of the Magma concept is the use of high CR without compromise to mainstream full-load performance levels. This paper will focus on development of the Magma combustion system using a single-cylinder engine, including valve event, air motion and injection strategies. 1-D simulation work will also be drawn from, particularly in considering boosting system options. Stoichiometric and lean-burn combustion system options have both been considered, but stoichiometric operation is the focus of the present paper.