The 2026 regulatory revolution brings numerous changes, and fuels are among the most significant. The reasons are twofold: while fuels must now be highly sustainable and no longer derived from fossil sources, the technical regulations also place emphasis on different aspects compared to the past. With the limit on the energy flow into the engine, the focus now lies primarily on fuel density to reduce the car’s weight and size, explains Valeria Loreti, Shell Motorsport Technology Manager.
The importance of density
Traditionally, the most important parameter for fuel has been its energy content – the chemical energy released during combustion that can be converted into power at the wheels. In previous power units, this value had to fall within a narrow window, with a maximum threshold on the fuel that could be injected into the engine per unit of time. The 2026 regulations, however, introduce a substantial change by directly limiting the chemical energy flow of fuel injected into the combustion chamber.
This shifts priorities for suppliers, including Shell, Ferrari’s partner, highlighting other parameters. “Beyond energy content, density is also important,” Valeria Loreti explains. “The mass flow of fuel is no longer regulated, meaning that if a given volume of fuel has low energy, you need more of it, increasing weight. Higher energy density means less fuel is consumed for the same energy flow, allowing a smaller tank, benefiting weight distribution and aerodynamic packaging.”
“In theory, you can explore a wide range of solutions,” Valeria Loreti continues. “I believe this is the first time that the way we make the fuel can even influence the shape of the car, such as where the tank is positioned.” Higher energy density also allows a car to complete a Grand Prix distance with less fuel onboard, reducing race weight and further cutting consumption. “The less you carry, the better,” confirms Shell Motorsport’s Delivery Manager. “There will be an energy flow limit, so having a high-density fuel is an advantage.”
A major opportunity
Valeria Loreti emphasizes that 2026 fuel development also involves other factors: “Temperatures, combustion pressures, stoichiometric ratio… all parameters defining the relationship between fuel and engine are critical. As formulators, we develop these special fuels based on chemical knowledge – molecules, combustion chemistry, burn rate, efficiency, etc. But we must also collaborate closely with engineers, understanding how combustion differences affect performance and, conversely, proposing certain compositions to optimize various parameters.”
Although the new engines retain the V6 architecture of the previous generation, what happens inside is radically different. The 2026 rules specify new limits for compression ratio and turbo pressure, allowing only a single spark ignition compared to the previous five, significantly altering combustion regimes and how they are controlled. This forces Shell and other suppliers to rethink fuel formulations. “Every time there’s a regulation change and we can modify combustion thermodynamics, it’s an opportunity to improve and reshuffle the deck,” Valeria Loreti comments. “It’s a continuous exchange: engineers share their vision, where they want to go and which parameters to adjust, and from this, we understand how to start formulating the fuel.”
New development techniques
The 2026 cycle will be another chapter in the long-standing Shell-Ferrari collaboration, ongoing for 75 years. Over time, fuel development techniques have continuously evolved, and this occasion is no different. “In the early 2000s, everything was done in the lab. Very experienced people visually assessed mixtures and then measured parameters. They prepared 30-40 fuel candidates, selecting perhaps 10 or fewer to produce in larger quantities for engine testing.”
“Now, engine testing is limited. Additionally, with digital models, we can choose candidates with the highest probability of peak performance in certain areas, optimizing one parameter or another.” Just like aerodynamics, fuel development relies on correlating virtual development models. Valeria Loreti concludes: “For the fuel we put on track, we conducted over a million simulations to select one, which is definitely different from starting with 20 or 30 candidates. Even then, validation testing is essential, as the model may not be entirely accurate. It’s a continuous loop, where the model interacts with Ferrari engineers’ models to make predictions from their perspective.”
The 2026 Formula 1 regulations are shifting the focus of fuel development toward energy density and chemical efficiency, potentially allowing teams like Ferrari to rethink car architecture and fuel tank placement. Through the use of advanced digital simulations and a 75-year partnership, Shell is aiming to provide a competitive edge that goes beyond the engine, influencing the very shape and weight of the next generation of racing cars.
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