Mercedes may still have the benchmark power unit in Formula 1 in 2026, but according to engineer Riccardo Romanelli, its advantage over Ferrari is not primarily about maximum combustion-engine horsepower. The decisive difference lies deeper within the hybrid system: how effectively electrical energy can be managed and deployed throughout an entire lap.
Ferrari has made progress with its ADUO2 power unit upgrade, yet Romanelli believes the Scuderia is still giving away performance to the leading Mercedes-powered cars in this crucial area. The difference can become particularly costly in qualifying, when extracting every fraction of a second from a single lap matters most.
Madrid reopens the Ferrari vs Mercedes power unit debate
The Spanish Grand Prix in Madrid provided another interesting indication. Madring does not feature the same kind of extended straights found at Monza or Baku, so it is not necessarily the ideal circuit for judging outright maximum speed. Even so, Mercedes-powered cars again remained at the front.
Romanelli does not believe that pattern is coincidental. Across several races, Mercedes and McLaren have continued to fight consistently for the leading positions, while Ferrari has generally appeared more competitive over a race distance than in qualifying.
That contrast was also visible in Madrid, where the broader Spanish Grand Prix technical analysis of Ferrari’s race pace and Madring difficulties highlighted the different strengths and weaknesses of the SF-26. For Romanelli, the power unit comparison helps explain part of that picture.
Mercedes advantage is not simply about combustion-engine power
For months, much of the discussion around Ferrari’s 2026 power unit has centred on how much horsepower the manufacturer recovered through the ADUO1 and ADUO2 development opportunities. Romanelli argues that focusing solely on that figure risks missing the more important issue.
The internal combustion engine certainly contributes to performance, but under the 2026 Formula 1 regulations it represents only one part of the complete power unit. Judging the package purely by horsepower ignores the interaction between the combustion engine, the electrical system and the software controlling how energy is used.
According to Romanelli, Ferrari did achieve a performance gain with ADUO2, but the improvement is relatively limited. On its own, it is not enough to account for or eliminate the gap that has appeared on track.
Energy deployment is the key to Mercedes’ 2026 advantage
Romanelli identifies one concept as central to the comparison: deployment.
The modern Formula 1 power unit must determine where and when to use the electrical energy available from the battery and MGU-K. The way that energy is distributed around the lap directly affects acceleration and therefore overall lap time.
Some power units can sustain electrical assistance almost all the way to the next braking point. Others can reach the end of their planned electrical deployment tens of metres before the driver begins braking.
When that happens, the driver is still accelerating, but the additional electrical contribution is no longer available and the car must rely more heavily on the internal combustion engine alone.
The difference may appear small at a single point on the circuit, but it can accumulate as the same situation is repeated from corner to corner and straight to straight. That is why raw speed-trap figures do not always tell the full story. Recorded differences can also be explored through the F1 Top Speed Comparison, although Romanelli’s argument concerns the entire acceleration phase rather than simply the maximum number reached at the end of it.
Where Ferrari loses ground at the end of the straights
Romanelli uses a simple example to illustrate the distinction between the two power units. A Mercedes can continue receiving electrical assistance until very close to the braking point. Ferrari, under certain conditions, can finish its deployment earlier and reach the final metres of the straight with less combined propulsion available.
The issue, therefore, is not only the top speed recorded at the end of the straight. It is the complete acceleration phase leading up to the braking zone and how consistently the power unit can continue providing its strongest combined output.
This sustained energy delivery is one of the characteristics Romanelli believes makes the Mercedes power unit so effective. It is also why circuits with demanding energy requirements can expose more than a simple horsepower deficit. Baku will provide another relevant test, with the SF-26 facing particularly demanding energy deployment requirements on its long straights.
Why Ferrari’s ADUO2 upgrade is not enough yet
The introduction of ADUO2 has improved Ferrari’s power unit, but Romanelli cautions against expecting a revolution from the update.
The development allows Ferrari to refine the operation of the complete power unit, but the resulting performance recovery remains limited when compared with the advantage Mercedes has built through energy management.
Ferrari has therefore taken a step forward, but the technical benchmark remains ahead. The gain from ADUO2 matters, yet it does not by itself resolve the wider challenge of extracting and sustaining electrical performance throughout the lap.
Madrid showed the Ferrari SF-26 has improved in race trim
While qualifying continues to expose one of Ferrari’s weaknesses, the Madrid race presented a more encouraging picture of the SF-26 over a longer distance.
Charles Leclerc completed a very long stint while maintaining competitive pace and avoiding the major performance drop-off seen during some previous Ferrari seasons. According to Romanelli, that demonstrates that the SF-26 has become a considerably more balanced car in terms of tyre management and race pace.
The greater difficulty appears when Ferrari needs to extract all of the available performance over one qualifying lap. In those conditions, relatively small differences in energy deployment can have a greater impact because there is no opportunity to compensate through consistency over a long stint.
The F1 power unit now works as one integrated system
One of Romanelli’s central points is that the internal combustion engine and electrical system can no longer be treated as separate performance areas. The 2026 Formula 1 power unit operates as one integrated package made up of several closely connected elements:
- the internal combustion engine;
- the MGU-K;
- the battery;
- the energy-management software.
Each component influences the others. Improving the combustion engine can also create opportunities to change how electrical energy is used, but Romanelli believes the deployment strategy itself now determines a significant part of the car’s overall competitiveness.
That relationship between combustion performance, electrical energy and software is becoming one of the defining technical themes of the 2026 season.
Why Mercedes performs strongly on very different circuits
Romanelli also highlights another significant detail: Mercedes’ advantage is not appearing only on one particular type of track.
The performance has remained evident across circuits with very different characteristics, suggesting that the advantage cannot be explained exclusively by aerodynamic configuration or outright top speed. Effective power unit management allows the overall package to remain competitive in a variety of conditions.
That consistency is one reason Mercedes continues to represent the technical reference point in 2026. The wider performance of the W17 can also be examined in the analysis of Mercedes’ 2026 competitiveness.
Can Ferrari still close the power unit gap?
The season is not yet completely settled from a technical development perspective. Ferrari’s updates to the SF-26 have shown that the team has managed to improve several areas of the car during the year.
However, Romanelli stresses that at this stage of the championship, further power unit developments can only alter the competitive picture to a limited extent. The most important work remains the integration between the internal combustion engine, electrical management and control software.
That development philosophy also has implications beyond the current campaign, because Ferrari believes that continuing to develop the SF-26 can provide useful gains for its 2027 project.
Ferrari’s biggest deficit may not be horsepower
The original question therefore produces a more complex answer than simply identifying which manufacturer has the most powerful combustion engine.
Mercedes does not appear to hold its 2026 Formula 1 advantage solely because of outright internal combustion engine power. According to Riccardo Romanelli’s technical analysis, the real strength lies in the quality of its electrical energy management and its ability to sustain deployment throughout the lap.
Ferrari has reduced part of the deficit with ADUO2 and improved the efficiency of its power unit, but Madrid reinforced where the remaining gap may be most significant: using all of the available electrical energy effectively until the final metres of the straight.
For the SF-26, that difference can influence far more than the number shown on the speed trap. It affects the entire acceleration phase, and in the tightly compressed margins of Formula 1 qualifying, that is where an important part of the performance battle is currently being decided.
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