The FIA has confirmed revised technical regulations for the 2021 World Rallycross Championship. The rules regarding car construction remain largely unchanged from the current regulations, with the exception of tweaks to safety requirements. For example, window nets and internal restraint nets are now compulsory, with the rules requiring they must be releasable by the driver when belted in.
More significant are changes to the engine rules, specifically those related to permitted engine layouts under the ‘custom’ engine regulations. Previously, only I4 engines were allowed, but the rules now accommodate boxer type, four-cylinder units.
These engines could always be used if based on a road car block and heads, but not if they featured custom-made block and heads. The change means that it is now theoretically possible for Subaru-based entrants, such as Subaru Motorsports USA (run by Vermont SportsCar), to run cars that have to date not be eligible for FIA competition, due to their use of bespoke engines.
Further engine-based rule changes will come into effect from 2022, such as a limit of just one homologated ALS (anti-lag system), with tighter controls on the layout of such systems. Additionally, there will be a ban on multiple, mechanically controlled throttle bodies, with builders limited to a single, mechanical or electronic throttle valve.