1.5 million lines of code: Software becomes a key factor in Porsche's new Formula E car

With the Gen4 975 RSE, Porsche will enter a new era in Formula E at the end of 2026. The chassis, aerodynamics and battery are standardised components, but behind the scenes, manufacturers are engaged in a complex development race. Software is playing an increasingly important role: According to Porsche, more than 1.5 million lines of code are contained in the control units of its new race car alone. For the Weissach-based manufacturer, its in-house software expertise has long since become a crucial performance factor.

The scope for in-house development remains clearly defined in the Gen4 era. Porsche and its rivals are allowed to develop parts of the rear powertrain as well as the operating software themselves. Porsche already explained in detail earlier this year which components manufacturers are allowed to develop themselves on the Gen4 car.

The importance of software is increasing even further with the new generation of cars. In the Porsche 975 RSE's control units, those more than 1.5 million lines of code are spread across well over 100 individual software modules. Each of them serves a specific purpose.

"This software maximizes the power we have at the wheel," explains Olivier Champenois, Technical Project Leader Formula E at Porsche Motorsport. That is why Porsche considers developing its Formula E software in-house so important: It allows the manufacturer to react more quickly to changes and new challenges while keeping development cycles short.

Porsche sees this as one of the key performance differentiators between Formula E manufacturers. By developing the software itself, the company says the knowledge remains entirely in-house and, in particular, with the employees who also support race operations.

Gen4 makes software even more complex

Gen4 adds another level of complexity. According to Champenois, the Gen3 car was already complex, but the systems in the new generation go significantly further. One reason is the additional freedom in calibrating and controlling the differentials. Unlike many hardware components, software offers scope for continuous development and optimisation throughout the Gen4 era. While manufacturers have to define important hardware components long before the first race, they retain considerably more flexibility when it comes to software.

During a visit to Weissach a few weeks ago, e-Formula.news gained an insight into Porsche Motorsport's Formula E department, including areas where work on the development of the 975 RSE takes place. However, a large part of the work on the new car happens virtually, long before the first real-world test kilometre.

Porsche is not alone in this approach: Stellantis is also making extensive use of simulations in the development of its Gen4 powertrain. The concept phase for the Porsche 975 RSE began in 2024, with simulator work starting in the same year. According to Porsche, manufacturers received the first official data for the new generation of cars in summer 2024. Individual components are also integrated into digitally simulated vehicle environments on test benches. This allows systems to be tested even when the physical car exists only in fragments.

Virtual development cannot completely replace real-world testing, however. According to Porsche, even state-of-the-art simulators and test benches still fall short of reality by around two to three per cent. Especially in motorsport, where tiny deviations can make the difference between victory and defeat, track testing therefore remains essential. Pascal Wehrlein and Nico Müller have been testing the 975 RSE on track since November 2025.

Around half of the race energy comes from recuperation

The importance of software becomes particularly apparent in energy management. Among other things, it controls how much energy is recovered under deceleration and fed back into the battery. The permanent all-wheel-drive system of the Gen4 car allows for recuperation of up to 700 kW. According to Porsche, around half of the energy used by the 975 RSE during a race comes from recuperation.

This is a central part of the Gen4 concept: The usable battery capacity is just 51.25 kWh. According to Porsche, only around half of the energy required over the full race distance is therefore stored in the battery at the start. The car recovers the remainder through recuperation during the race.

The electric motor on the rear axle alone can recuperate with up to 350 kW of power. Porsche uses direct oil cooling, with non-conductive oil flowing directly along the stator windings. According to the manufacturer, an electric motor with conventional water-jacket cooling and comparable performance would have to be around one and a half times larger.

The development of the 975 RSE also illustrates how much the development landscape in Formula E has changed. The regulations impose tight restrictions on many hardware components, while software, control strategies and the most efficient possible use of the available energy are becoming increasingly important. With Gen4, the competition between manufacturers is therefore likely to be decided increasingly in areas that remain almost completely invisible from the outside.