F1 2026 engine changes: why adjusting the hybrid-thermal ratio risks a major setback. 2026 Engine Rules: Why the Latest Proposal Could Undermine Everything.

A recent report from Auto Motor und Sport revealed that some engine manufacturers are seeking to change the power distribution between the thermal and electric components just months before the debut of the 2026 power units. However, the proposal appears unfeasible unless one is willing to invalidate the development work carried out by each participant. A change of this kind would, in fact, compromise the viability of the design concepts already chosen by the teams, both in terms of the power unit and the chassis.

Electric power affects aerodynamics
Under the current regulations for the 2026 power units, output is roughly split 50/50 between the hybrid system and the internal combustion engine. These percentages are only indicative, as peak electric power will only be available for short bursts, with battery energy needing to be spread out over the course of a lap. The proposal on the table suggests adjusting the balance between combustion and hybrid power, at least for the first few years, shifting it to 80%-20% or 70%-30%. It remains unclear how this adjustment would be implemented, but it would pose major issues.

One option would be to reduce the hybrid system’s output, perhaps by capping peak performance and smoothing it out across the lap. Cutting electric power would effectively unify—or at least align—the different power delivery strategies. However, these strategies have already shaped the teams’ car concepts. Lowering hybrid performance would impact the work done so far in terms of aerodynamics and chassis design, and would also require smaller radiators due to the reduced heat generated by the hybrid system. Moreover, engine manufacturers have already developed batteries, inverters, and electric motors designed to handle higher output, meaning a late change would penalize those who have made more progress.

Increasing thermal power isn’t simple
Another issue would be boosting the thermal engine’s performance to maintain overall power output. This could be achieved, for example, by increasing turbo pressure, which would require redesigning the turbocharger to operate at higher speeds. Increasing fuel flow would be another effective strategy, but that would necessitate a larger fuel tank. All of this would raise race weight and increase packaging volume, influencing both chassis and aerodynamic choices.

In general, even without changing displacement or other geometric parameters, boosting thermal performance would mean higher pressures and temperatures in the combustion chamber, requiring a redesign of several components to withstand the added stress. The engine would also function less as a generator for the battery and more as a propulsion unit, shifting its optimal operating point. And all this with the designs already nearing completion.

The alternative might be to leave the thermal performance untouched, but in that case, cutting electric power would reduce total output. Besides needing to quantify the lap-time impact, this power drop would force teams to reassess the vehicle concepts developed in recent months, pushing them toward greater aerodynamic efficiency. The proposal on the table, therefore, appears unworkable—unless one is prepared to compromise all the development that teams and engine manufacturers have undertaken so far.