18 months before the 1st Gen4 race: The hardware gamble behind Formula E's new car

Stellantis had to make crucial decisions about its Gen4 powertrain long before the new Formula E car ever took to the track. Around 18 months before its first outings, key components already had to be ordered even though only limited information about the new tyre was available at the time. Simulation engineer Teena Gade explains why manufacturers are effectively making a technical gamble with Gen4 and how the new token system is designed to allow corrections later on.

Stellantis began developing its Gen4 powertrain for the Citroen and Opel teams as early as January 2024. Initially, much of the development took place virtually through simulations of a car that did not even physically exist at the time. Yet those calculations soon had to result in real hardware decisions.

A lot is new with the Gen4 car. Permanent all-wheel drive and up to 600 kW of power place very different demands on the components compared with its Gen3 predecessor. The tyre is new as well, with Bridgestone replacing Hankook from Season 13. Its grip level influences, among other things, the torque required and the loads placed on the car. Initially, manufacturers only knew the expected increase in grip compared with the Gen3 tyre, yet the first components already had to be defined.

Magnets had to be ordered 18 months before they were needed

"The tyre is the single biggest factor," Teena Gade explains to e-Formula.news during Citroen Racing's test drives in Guadix. "You never know exactly how much grip the tyre is ultimately going to have. But very early in development, you have to define certain components of the car and essentially lock them in."

"When Gen4 was launched, we already had to order the magnets that we would need around 18 months later for the first tests and races," Gade says. "Even then, we had to know which magnets we wanted. The magnets and the copper define the performance window of the motor-generator unit. That's why we had to make that decision very, very early."

For the Gen4 car, manufacturers are responsible for developing components including the rear MGU and inverter. Their exact specification determines the operating range in which the powertrain is particularly efficient or powerful. Copper and high-performance magnets are key elements in that equation. The physical hardware therefore had to be specified long before the first race appearance.

Development planning works backwards from the date on which the finished components are needed, Gade explains. "You have to work backwards: I need my first motor-generator units and my first inverters on this date. So I need to work out by when I have to decide exactly what those parts are going to look like."

Stellantis was not in a unique position, however, as every manufacturer faced the same challenge. "It was the same for all the manufacturers. We all had the same information at the beginning." On top of that, manufacturers make their decisions largely independently of one another. Which technical direction their rivals have chosen and how competitive their own solution is by comparison will only become clear once they meet on track.

Token system can help correct development mistakes

The new token system should, however, make it possible to correct a wrong development direction more quickly, Gade explains. While manufacturers were tied to their homologation for two seasons at a time under Gen3, they have greater flexibility during the Gen4 cycle. From Season 14 onwards, they will be able to spend tokens on defined areas of the car ahead of each subsequent season and homologate further developments.

A manufacturer that gets everything right from the start may, conversely, not be able to benefit from its advantage for quite as long. "If you arrive at the first race and you're terrible, you're going to love the token system. If you arrive at the first race and you're two seconds ahead of everybody, you're going to be pretty unhappy about it."

A complete change of direction would still be difficult. The cost cap, limited personnel and available development capacity impose restrictions even with tokens. "If we realised in January that we needed to make a complete U-turn and change the entire philosophy of the car, that would be pretty difficult."

"Which system is better? It depends. If you're miles ahead of everyone else, you don't want the token system. If you're miles behind everyone else, you definitely do."

Gade cannot yet assess where Stellantis stands with its chosen concept compared with the competition. "In the end, it's the age-old question: What is everyone else doing? And we just don't know. In a year, I can tell you whether we got it right or not."