The World Rally Championship’s introduction of new Rally1 regulations is perhaps the most significant shift in rules and technology in rally history.
The rules have created arguably the biggest technological challenge for Toyota, Hyundai and M-Sport Ford to construct all-new hybrid Rally1 machines from the ground up to meet strict new criteria in a short space of time. Added complexities created by the Covid-19 pandemic on staff and component suppliers has made the process a unique challenge.
A move to a more sustainable future is the principle behind the Rally1 concept as the WRC adopts a more environmentally friendly approach it hopes will keep the championship relevant in the eyes of manufacturers, and in time will attract new brands to the fold.
The most significant change is the advent of hybrid power, a brand new challenge for the WRC and its teams to conquer. This is followed by a move to simplify technology elsewhere, reduce the effectiveness of aerodynamic devices and remove trick differentials to fine tune handling.
The result of these sweeping rule changes is the creation of all-new beasts in the form of M-Sport’s Ford Puma, Hyundai’s i20 N and Toyota’s GR Yaris. All three are capable of producing 500 horsepower in short bursts when the hybrid unit and internal combustion engine are working together. While the cars are less technical in areas and heavier, safety for driver and co-driver has improved compared to their predecessors, courtesy of new tougher FIA regulated space frame chassis.
Chassis
The chassis is no longer built around the production road car with teams constructing their machines from scratch. New tougher and safer steel space frame chassis, regulated by the FIA, form the base of the car, built to a minimum wheelbase for the first time.
According to the FIA’s tests and research, side impacts showed a 51% reduction in intrusion. The roof section can absorb energy up to 115% better than a previous WRC body shell reinforced by a traditional roll cage. A frontal impact against a rigid obstruction resulted in 70% less intrusion in the bulkhead area, protecting the crews feet and legs.
Hyundai’s Thierry Neuville has already hailed the new safer chassis for allowing him to walk away from a nasty testing crash in December.
Engine and hybrid
The 1.6 litre internal combustion engine (380 horsepower) remains but it’s now coupled to a control 100kW hybrid system designed by Compact Dynamics. Working in tandem, the car can produce 500 horsepower in short bursts. The hybrid system’s 12,000rpm motor is connected to the prop shaft delivering power to the front and rear wheels.
An extra 130 horsepower can be delivered through hybrid boosts lasting no longer than 10 seconds, initiated by the throttle pedal. Energy can be recovered when off the throttle and under heavy braking. The extra power is delivered through the use of three bespoke homologated engine maps selected by teams, depending on the type of stage and conditions.
In full electric mode the car has a range of 20km, while its 3.9KWH battery, operating up to 750 volts, can be plugged in and recharged in the service park within 30 minutes. The hybrid unit can withstand an impact of 70G.
Gearbox
The six-speed paddle shift has been replaced by a mechanical lever operated five-speed sequential gearshift.
Aerodynamics
The new regulations have effectively abolished extra aerodynamic devices such as wings and flicks being added to the bodywork outside of the front splitter and rear wing. The overall downforce created and its effect on the car has been reduced by approximately 15% compared to the previous generation of vehicle.
Heavier cars
Cars will be up 70kg heavier than their predecessors, this is mainly due to the addition of the hybrid system. In total, Rally1 machines will weigh in at approximately 1260kg.
Differentials
Trick centre differentials used to fine tune handling are now banned in favour of a simpler front and rear mechanical limited-slip differentials offering a fixed 50:50 toque split between the front and rear wheels.
Suspension
Suspension travel has been reduced to 270mm. While this will have no effect on tarmac, the difference will be noticed on rougher gravel rallies.
Tyres and Brakes
To cope with the extra weight of the cars, Pirelli has altered the construction of its tyres to counteract the effects of the extra load and wear being placed on the rubber. Air-cooled 300m brake discs will be used on tarmac rallies, with 370mm versions fitted for gravel events.