Ferrari: Charles Leclerc’s strange team radio and the Power Unit 066/15 issue in Japan. Ferrari, the radio enigma of Charles Leclerc regarding the power unit 066/15.

Ferrari, with Lewis Hamilton and Charles Leclerc, did not disappoint expectations in the third round of the 2025 Formula 1 season, meaning that they themselves did not expect anything more than what they achieved in the Japanese Grand Prix at the 5.807-kilometre Suzuka Circuit. It may sound like a joke, but it is not at all. Yes, because as the Monegasque driver said after the race, it really hurts to give everything and achieve so little. A fourth and a seventh place are insufficient, a result that frustrates the fans.

The resignation of Ferrari drivers is difficult to accept. Lewis Hamilton commented on his performance as “nothing exceptional,” and then emphasized that the Maranello team still has several gaps in understanding certain aspects. Therefore, he does not hide the sheer need to make progress. The different tire strategy, with the hards in the first stint and the mediums for the second part of the Japanese Grand Prix, worked very little, recovering only one position. His pace was not at the level of those ahead of him due to a series of issues he suffered from.

It was exactly what the seven-time Formula 1 world champion expected, considering the handicap suffered in the qualifying session and the subsequent starting position, which in Suzuka is hard to overcome. For Charles Leclerc, there is a mix of awareness and frustration. Some sensations were better, with clearer ideas on how to act, although his SF-25 single-seater did not satisfy him at all. Such a significant gap to Red Bull and McLaren made him suffer.

With one eye already focused on the Bahrain Grand Prix weekend, the Ferrari driver hopes that Sakhir can offer more satisfaction, where the car’s overall package should perform better than in Japan. In theory, the first aerodynamic updates are expected for the upcoming weekend, despite the fact that Ferrari team principal Frederic Vasseur seemed vague, stating that before adding any new features to the car, the Maranello team’s technicians and engineers need to fully understand it. “It’s about understanding,” a refrain endlessly repeated by Mattia Binotto which shows how well Ferrari is doing in the start of the 2025 Formula 1 championship.

What happened to the power unit 066/12?
But today we want to focus on an incident involving both of cars of the Italian side at the Suzuka circuit. An interesting issue on which we are unlikely to receive news from the historic Ferrari team. On the other hand, it is standard practice, as explaining some unclear matters, especially on a technical level, is not at all within the Italian team’s choices. Let’s recount the facts to get an idea.

Based on the telemetry data of Lewis Hamilton’s Ferrari SF-25 and Kimi Antonelli’s Mercedes W16 from lap 46 of the Japanese Grand Prix, there is an aspect that makes us reflect: The British driver’s’ Ferrari lacks power at the end of the straights. Car number 44 reaches its speed plateau too early, with clipping leading to a speed reduction of up to -5 kilometers per hour. Moreover, in front of the TV cameras, the English driver talks about a problem that made them lose at least 1 tenth per lap. At this point, another element needs to be mentioned to connect all the dots. Mid-race, Charles Leclerc was repeatedly asked to switch to Engine 1. We are talking about the more aggressive mode for using the internal combustion engine.

But the Monegasque driver has always refused, and on the radio, he said these exact words: “You’ve already told me this several times, but if I don’t do it, there is a reason.” Reflecting on the Ferrari driver’s team radio communication with his race engineer Bryan Bozzi, we can imagine that on the dashboard of car number 16, there were numbers that were far from reassuring. Was it a different management of the hybrid system or perhaps some reliability issue? Lewis Hamilton’s telemetry suggests that something was indeed not functioning properly. Engine modes are usually dictated by the engineers on the track.

For this reason, it is very strange that a driver would deny the use of a more aggressive engine mapping. They could do this with the hybrid system, to avoid “burning” the amount of energy needed to defend against an opponent. Or maybe because they realize that the mode to “spread” the horsepower recovered from the motor-generators is ineffective. Meanwhile, with the internal combustion engine, it is a matter of consumption, which is presumed to be under control by the pit wall through the data received from the sensors installed on the car.

The doubt about the power unit will remain just that. Let’s clarify further, assuming that the issue was not related to fuel. Not using maximum power on the internal combustion engine at certain points during a Grand Prix is generally and logically done to avoid reaching critical temperatures with the power unit or for any element that could directly compromise the engine’s health. Therefore, it is very strange for the Monegasque driver to deny this, as, like the English driver, he suffered from the same issue.

Even more so if we add Lewis Hamilton’s comments on the issue, which, in fact, reduced the performance of the SF-25 single-seater every single lap. However, the mystery of this team radio message is destined to remain a mystery because, as mentioned earlier, Ferrari is not in the habit of providing any kind of explanation. They really don’t like it and prefer to drop a mysterious veil over the events.

A clear approach to avoid controversy, which often, however, ends up fueling it. In this scenario, we must add the last piece of the puzzle. At the beginning of the race, the top speeds of the two Italian cars were higher and they did not suffer from that type of clipping, precisely at the moment when the fuel load onboard was significantly higher, and the power needed to achieve good top speeds was greater.

— see video above —