Key among the changes enabling this is a brand-new gearset similar to that already used by the second-generation Panamera and Cayenne. Achleitner, who is set to retire at the end of 2018, says the new gearset is almost 100mm shorter than the old one, providing space in the rear of the gearbox to house the motor.
As well as adopting a new gearset, the ZF-produced eight-speed PDK unit also has a higher torque rating than its predecessor at “over 800Nm [500lb ft]”, in a move that Achleitner says is necessary to allow the 911 hybrid to handle the strong torque loading of the motor.
The 911’s four-wheel drive system has also been reworked to allow up to 50% of drive to be apportioned to the front wheels. A further change centres around the brake booster. Similar to that used by the discontinued 918 Spyder, it forgoes the electromechanical operation of the previous 911's unit for a fully electric set-up. This allows a much more significant recuperation of energy, both under braking and on the overrun.
Achleitner wouldn’t be drawn on the specification of the petrol-electric hybrid 911, but he points to the Panamera S E-Hybrid as a performance reference. The more powerful of two hybrid Panamera models, this has an electric motor developing 134bhp and 218lb ft. This is combined with the 542bhp and 568lb ft of its twin-turbocharged 4.0-litre V8 petrol engine to provide an overall system output of 671bhp and 626lb ft.
Applying the power and torque developed by the Panamera S E Hybrid’s electric motor to the new 911 Carrera S would provide it with a theoretical system output of 578bhp and 686lb ft – some 21bhp less but a significant 133lb ft more than the previous-generation 911 Turbo S. This model had a claimed 0-62mph time of 2.9sec and top speed of 205mph.
The battery used to power the electric motor in the 911 hybrid is expected to be housed within the front. Despite bringing added weight, this is expected to greatly improve the weight distribution of standard petrol engine-only versions of the new 911, which is put at 39:61 in the initial 1515kg Carrera S model.
The lithium ion battery used by the Panamera S E-Hybrid has a capacity of 14.1kWh, sufficient to provide the 2410kg five-door liftback with an official electric-only driving range of up to 31 miles on the old NEDC test procedure.
Another advantage brought by the adoption of a battery pack in the front of the 911 is a reduction in the centre of gravity. Nothing is official at this stage, but insiders suggest early 911 hybrid prototype mules feature a smaller fuel tank than conventional models, allowing the battery to be mounted low down within the car's front end.