Clever engine maps prevent the engine pushing the car on in these conditions by retarding the ignition by as much as 35-40% on the over-run.
To do that they have to retard the ignition and kill the torque, because if you don’t then the engine is going to create torque and the engine is going to keep going when the driver lifts off the throttle.
This fuel is not igniting inside the engine cylinders, but pass trough and ignites on the hot exhaust, increasing the amount, speed and temperature of the airflow exiting towards the diffuser. In hot blowing they cut the ignition when the driver lifts off the throttle, but continue to inject some fuel through the engine’s valves into the exhaust to increase the energy into the gas.
