When a car, ready for launch is being held at its launch RPM limit some ECUs (whether by switch or additional throttle) can be programmed to retard the ignition by quite a few degrees and add a lot more fuel. This causes the combustion event to happen much later, as the engine is driving the air/fuel mixture out of the cylinder, closer to the turbine, causing it to spool up either at an earlier RPM than it would normally – assuming the engine unloaded waiting for launch or make more boost at the launch RPM than it would without engaging this feature.