In the lead-up to the 2025 Formula 1 Belgian Grand Prix, Scuderia Ferrari’s race engineer Roel Sourbron has provided detailed insights into the technical challenges of managing the power unit fitted to the SF-25 at the demanding Spa-Francorchamps circuit. This legendary Belgian venue, with its total length of 7.004 kilometres, is widely recognised as one of the most challenging and complete circuits on the Formula 1 calendar due to its high-speed sections, rapid elevation changes, and variable weather conditions.
From an engine performance perspective, Spa-Francorchamps places a dual strain on the power unit, as explained by Roel Sourbron himself. “The most critical feature of the circuit is the presence of two extended flat-out sections,” the Ferrari engineer stated. “The first includes the iconic Eau Rouge and Raidillon combination and is taken with the throttle fully open for 23 seconds, covering 1.8 kilometres. Despite having over 900 horsepower available, the car still loses speed while climbing, due to a gradient that reaches up to 14 percent.”
Ferrari’s power unit secrets for unlocking SF-25 performance at Spa
Another demanding section for the power unit is the second long flat-out stretch, which features the high-speed Blanchimont corner. “In that sector as well, the drivers keep the accelerator fully pressed for 20 seconds across 1.6 kilometres,” continued Sourbron. “These high-speed straights are separated by fast corners and a slow-speed chicane, so achieving the right balance between straight-line performance and efficiency in the technical sections is absolutely essential.”
Energy and fuel management also become crucial factors at Spa, given the track’s length and its impact on fuel consumption. “You need to calculate the amount of fuel with extreme precision in order to be as light as possible during the race. Every extra kilogram of fuel can cost lap time,” said the Ferrari engineer, highlighting how tightly weight is linked to competitiveness over a race distance.
Sourbron also elaborated on how Spa’s rapidly changing weather and atmospheric conditions affect the power unit’s overall performance. “Spa can offer everything from cold and rain to warm sunshine. In hot conditions, the engine faces serious challenges in terms of cooling and pure power delivery. On the other hand, cold and humid weather results in high combustion pressures for extended periods, which places considerable stress on the engine’s internal components.”
Adding to the complexity, Spa’s unique geographical layout—characterised by more than 100 metres of elevation change and a maximum altitude of 461 metres above sea level—has a direct effect on air pressure. “Similar to circuits like the Red Bull Ring in Austria or the Autódromo Hermanos Rodríguez in Mexico City, the lower atmospheric pressure requires the turbocharger to spin faster to maintain performance levels, bringing it closer to its mechanical limits,” Sourbron explained.
Finally, the Ferrari engineer discussed how wet conditions can drastically alter driving styles at Spa. “In the rain, corners such as Eau Rouge and Blanchimont can no longer be taken flat-out. Under these circumstances, drivability and energy recovery management become far more important than outright engine power,” he concluded.
Through these detailed explanations, it becomes clear that Ferrari is relying on a sophisticated, data-driven approach to extract the maximum from the SF-25’s hybrid power unit at Spa. The team’s understanding of how to adapt engine performance to varying track conditions could play a decisive role in the outcome of the Belgian Grand Prix.
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