This mode was developed specifically for the European 4G93 GDI. Fuel is injected twice: a small amount early, and the majority late. Early injection cools the cylinder. The air-fuel ratio at this point is extremely lean, up to 60:1, so it does not spontaneously ignite. When the rest of the fuel is injected, the air-fuel mixture becomes very rich - about 12:1. This rich mixture is completely combusted. The result: at 650 rpm, a 55 percent increase in torque, for the power to pull away fast. Two-Stage Mixing 1. Piston moves downward. 2. Fuel is injected. 3. Fuel is injected again during compression stroke. 4. Sparkplug ignites mixture.