https://docs.emtronaustralia.com.au/engine-management/tuning/throttle-mass-flow/throttle-mass-flow-outflow/index.htmlOverview The Outflow Function describes the relationship between the pressure ratio across the throttle and the amount of air that can flow through it. As the pressure ratio changes, the relationship between pressure and airflow also changes. The Outflow Function models this behaviour and forms a critical part of the modelled throttle body fluid dynamics used in the TMF (Throttle Mass Flow) calculation.Hugoen-us