Ferrari SF-25 vs McLaren MCL39: ERS management and weight influence race pace. Ferrari and McLaren certainly used different power unit modes in Bahrain F1 testing.

Ferrari is preparing for its objective in the start of the 2025 Formula 1 championship: to beat McLaren and be competitive right from the first round of the new season, which is scheduled to take place this weekend at the 5.278-kilometre Albert Park Grand Prix Circuit in Melbourne on Sunday. A leading role, in short, where maximum attention to every detail will be crucial. Coming out well from the pre-season testing session at the Bahrain circuit was not easy. The Maranello team did not perform poorly, to be clear. However, several issues arose, some expected, others less so. But this is normal, as it is rare for a new car to hit the track and dominate immediately. The Woking team certainly seemed much more prepared at this stage of the preparations. That is undeniable and it does not mean that the Italian side cannot fight to achieve to its target this season.

Nevertheless, even the reigning world champions faced some headaches. McLaren team principal Andrea Stella was cautious, stating that during the Sakhir track testing session, they were unable to assess their rivals’ performance and mentioning some balance issues with the car on the second day. The former Ferrari race engineer believes that they are not the favorites, therefore, especially considering last season’s approach in the Middle East. It should also be noted that the two MCL38 cars appeared to have masked their performance in Sector 3, relying on an already strong competitiveness without pushing in that section.

Based on the data collected from the Bahrain pre-season testing runs, we can clearly notice differences in engine mapping between the two teams that fought for the Formula 1 Constructors championship until the last round of the previous season, in Abu Dhabi. Ferrari and McLaren certainly used different power unit modes. If we examine the telemetry we have gathered for this specific comparison, we can easily observe this in the final segments of the four straight sections that make up the Bahrain circuit, a stop-and-go track where the ability to accelerate out of the slower corners and display good traction is crucial, along with top speed performance in the faster sections.

In this particular phase of testing, it is evident that Charles Leclerc loses significant speed, by as much as 6 kilometers per hour, despite keeping the throttle down for a few more meters than his British counterpart. This behavior could be due to inefficient use of the electric component of the engine at the end of the straights, leading to a loss of 0.040 seconds per acceleration phase. When summed across the relevant sections of a lap, this results in an overall performance loss of about two-tenths per lap.

Various telemetry data suggest that Charles Leclerc was running with more weight than Lando Norris for two possible reasons: more fuel on board or the use of ballast for specific tests (as former Ferrari driver Carlos Sainz himself suggested). First, in the snake section formed by turns 5-6-7, despite the Ferrari driver lifting off the accelerator at the same level as Lando Norris (or even less), he loses much more speed—up to 14 kilometers per hour in mid-corner. If the aerodynamic balance were similar, this loss could only be justified by the greater weight of the car, which hampers direction changes and inertia during load transfers.

Secondly, it is very evident that when exiting each corner (especially turns 1, 4, 11, 13, and 14), Ferrari’s speed curve is consistently lower than McLaren’s, even though both drivers apply the throttle at the same time. In other words, Ferrari struggles to achieve the same speed increase. There could be two reasons for this: a very limited use of the ERS, not only at the end of the straights but also in traction, or once again, more fuel or ballast on board. On this point, it is important to highlight that just 4 kilograms more implies a loss of 0.100 seconds per lap, while 10 kilograms mean a deficit of 0.250 seconds.

While analyzing the telemetry data, we notice the Ferrari driver shows a higher degree of aggression than Lando Norris. In turn 13, with this move, Charles Leclerc may have been executing a specific instruction from the Maranello team’s engineers in order to put more stress on the tires. Indeed, the Ferrari driver tackles this section almost flat-out (practically on every lap since the first stint), which, of course, is not ideal in terms of tire management. The difference in throttle usage is around 20% in full application, which is an interesting data point.

Telemetry analysis shows that despite the acceleration generated by the Italian car being almost identical to that of the British single-seater, Charles Leclerc demands much more mechanical grip from his tires. This effectively suggests greater stress on them. As mentioned, if this was part of a deliberate Ferrari strategy to test tire endurance over long runs, it would explain the gap in lap times and wear. However, it could also be the result of a stiffer setup, with the driving style used to compensate for the performance loss.

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