Listen to this article Some elements of the power unit can still be changed up until September this year, but after that, the manufacturers can’t make further changes, at least as far as performance is concerned.The overall effect is that the relative performance of the four power units used in F1 will remain unchanged for the duration of the freeze. What is an engine freeze? In essence the freeze represents a complete block on development by the four current Formula 1 power unit manufacturers: Mercedes, Ferrari, Renault and Honda (rebranded as Red Bull Powertrains). The specifications of each power unit has to be lodged with the FIA in a process that is known as homologation, which means to produce a component that is verified as legal and can be replicated in manufacturing to use in races but ther …