5 things you absolutely need to know before driving on E85 bioethanol

Even though the government discount on fuel prices has been in effect since April 1, 2022, unleaded and diesel remain very (very) expensive… and will not get cheap! How serious about using E85 to replace the 95 or the 98 in your tanks, the diesel blocks can’t run on ethanol anyway† Before you turn to this fuel for half the price at the pump, here are five points to remember.

1. To drive in E85 bioethanol, it is better to have a gearbox!

Need we remind you: bioethanol is a fuel that can be tolerated in absolute terms by all petrol engines. This means that even in the absence of a conversion kit, by refueling your car with E85, there is currently no risk of serious breakdown. You will likely see the engine light come on temporarily while the computer understands what is happening and adjusts accordingly.† Magic, you say. But in reality, this alcohol resulting from the fermentation/distillation of beets or wheat is not a substitute for lead-free. And to help our cars digest it better, a conversion kit is still preferable, for two reasons.

This kit, which is nothing more than an electronic box installed under the hood to increase the amount of fuel injected into the engine, will allow it to adapt faster to E85 and start better when cold. Because E85 contains less energy than SP95 or 98, it is necessary to inject between 15 and 20% more. In order to be approved, in addition to respecting the levels of polluting emissions of your car, the kit manufacturers must take out insurance that guarantees all damage related to the use of their kit and the E85 in your car.† Reassuring, even if there is a high risk of a battle of experts in case of mechanical problems!

Note that even with a box, the motor can still run unleaded. And that you can even, if you want, mix the two fuels at the same time…

2. Many models compatible with E85

Specialized sites list quite well the compatibility between your engine and the E85 kits. The approaches are often quite simple, as all you need to do is enter your license plate number to find out.† Even though roughly the vast majority of recent petrol cars qualify.

Some manufacturers offer bi-fuel as standard. This is the case with Ford on almost the entire range – and it even combines it with the hybrid on the Kuga SUV! – but also models from the Jaguar-Land Rover group. The E85 also ‘saved’ the sale of large English SUVs in 2021…

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3. Some risks to consider with E85 ethanol

Since the E85 is present in more than 2000 stations in France and almost all petrol engines accept it, one would be tempted to see only the good sides. But this forgets the more corrosive nature of bioethanol and the need for additional injection power. In the case of compatible models, once they are factory fitted, everything is planned to ensure perfect engine reliability. (modified fuel circuit, reinforced valves and valve seats, higher flow injectors, reworked advance curves, etc.). But for converting a car during its life, these costly operations are never performed by kit installers. More aggressive than lead-free, E85 therefore tends to make certain engine parts “work” a little more. Not enough to destroy it in the short term, but you have to take into account a higher risk of wear and tear† It is up to everyone to know, depending on the value of their car and its use, whether they take this risk or not.

With heavy use of the engine such as in the mountains, when driving sporty or towing, the flow rate of the injectors may be insufficient, so that in these cases we do not recommend the use of an E85 kit.

4. Will the manufacturer’s warranty be maintained if an E85 conversion kit is fitted?

Except for routine maintenance as recommended by the factory, any intervention on an off-grid motor to alter its operation will void the manufacturer’s warranty, which is the case with an E85 kit. Even Ford, which offers installation on the used models from its range, indicates that the manufacturer’s warranty no longer applies! With the exception of the original E85 engines, it is therefore useless to hope for better than an intervention from the insurance of your kit in the event of a problem with the parts of the engine that come into contact with the bioethanol.

5. Driving on E85 bioethanol: is it always a winner in use?

Small, however, the E85 housing is not cheap. The installation is billed between 700 and 1,600 € depending on the nature of the work† A nice ticket, but quickly becomes profitable, because if the use of bioethanol leads to overconsumption of the engine, the price per liter remains two times lower than that of unleaded. Especially since state and even regional aid is sometimes available. Again, specialized sites have simulators that calculate the savings based on your annual mileage† However, savings that can go up in smoke if you have a major mechanical failure…