Gasoline with 35% ethanol enters tests; understand what changes in your car

The federal government has formalized the test plan for E35 gasoline, a blend with 35% anhydrous ethanol, the maximum level authorized by the Fuel of the Future Law (14.993/24). The ordinance of the Ministry of Mines and Energy (MME) was published in the Official Gazette of the Union last Friday (18), and the tests begin in the coming days, and are expected to extend until 2027.

The schedule was approved on September 11 by the Permanent Technical Committee on the Fuel of the Future (CTP-CF), but the adoption of the new blend is not automatic: it will be up to the National Energy Policy Council (CNPE) to decide, after the results, whether the percentage increases. Until then, regular gasoline continues with 32% ethanol, and premium, with 25%.

The assessment comes shortly after the entry into force of E32, on August 1 of this year, received with resistance by vehicle manufacturers and importers. The Federal Public Ministry (MPF) even asked for the suspension of distribution. The increase from 30% to 32% is valid for 180 days, extendable for an equal period, and its permanence is conditioned precisely to the E35 tests.

Owners of flex-fuel cars should notice an increase in consumption. Ethanol has a lower calorific value than gasoline: each liter of the sugarcane derivative delivers about 70% of the energy of the fossil fuel. In the most recent vehicles, however, electronics compensate for part of the bill. This is because modern engines work with an intermediate compression ratio and, when identifying a fuel with a higher octane rating, the electronic management system can adjust itself and operate in a more efficient regime.

Old cars at the center of concern

The situation is more delicate in the old fleet, since excess alcohol can attack materials and corrode rubbers and elastomers, in addition to causing failures in sensors of single-fuel cars that do not recognize the mixture.

Many of these older vehicles were calibrated to run on 22% ethanol. Jumping to 35% would require caution even in controlling emissions, evaluates the engineer, who defends the offer of a fuel with a higher proportion of gasoline for this public. The obstacle is the price: today, the only option in this profile is the premium, more expensive at the pump.

Brazilian regular gasoline went from 22% to 27.5% ethanol in 2015, a level maintained for a decade. It rose to 30% in August 2025 and to 32% in August 2026.