E85 CONVERSION

E85 conversion: install a certified ethanol kit with RS-TRONIC

Filling up is becoming an increasingly heavy expense. With unleaded 95 and 98 octane above €2 per litre, E85 remains priced at around €0.83 per litre in France. E85 conversion using a certified ethanol kit allows your petrol vehicle to run at this price, in just a few hours, at an installer in the RS-TRONIC network near you. An officially recognised solution, which opens up the right to update your vehicle registration with the "FE" (Flex-fuel Ethanol) marking and to regional subsidies of up to €500.

80+

Installers

1000€

Average savings/year

Find an installer near you

What is an E85 conversion kit?

An E85 conversion kit (also called an ethanol kit or flex fuel kit) is an electronic module that connects between the sensors and the injectors of your petrol engine. Its role is simple: to adjust in real time the amount of fuel injected to allow your vehicle to run on E85 superethanol or on unleaded petrol, without modifying the original ECU.

Learn more

How does an ethanol conversion kit work?

Ethanol has a different energy density compared to petrol: to produce the same power, the engine needs to inject slightly more fuel. The kit automatically detects the proportion of E85 present in the tank and adjusts the injection parameters accordingly. You don't have to do anything: whether you fill up with unleaded petrol, E85 superethanol or a mix of the two, the kit adapts on its own at every start-up.

Installation is carried out with no mechanical modification to the engine. The kit is simply connected to the injector connectors and powered by the battery. It is a physically reversible solution: it can be removed at any time to restore the vehicle to its original configuration.

Certified vs non-certified kits

Not all kits on the market are equal. The most important distinction is official certification:

A certified kit (such as FlexFuel or eFlexFuel) meets the requirements of the French decree of 30 November 2017. It opens up the right to update your vehicle registration with the "FE" marking and to benefit from regional subsidies. Its installation must be carried out by an approved professional.

A non-certified kit (often sold online at very low prices) has no official validation. It doesn't allow vehicle registration update, doesn't qualify for any subsidies, and may cause problems in the event of inspection or vehicle resale.

OUR GUARANTEES

The RS-TRONIC guarantees

Certified installation by approved installer

Our 80+ dealers across France are ethanol kit installers trained in the installation protocols of the brands we distribute. You benefit from an intervention compliant with the manufacturer's recommendations, essential to validate the kit's manufacturer warranty.

Kit hardware warranty

Every installed kit comes with the hardware warranty provided by the brand (FlexFuel or eFlexFuel). The exact terms of duration and coverage are published by each manufacturer on their official website.

Recognised kit brands

RS-TRONIC installs only FlexFuel and eFlexFuel kits, two brands officially certified in France under the decree of 30 November 2017.

Post-installation follow-up

After installation, your RS-TRONIC installer remains your point of contact for any question, check or adjustment regarding your conversion.

Calculate your savings with an E85 kit

15,000 km
7.0 L/100
€1.85/L
€0.95/L
Annual savings*
€746 / year
€0 €1,000 €2,000+
Current annual cost on unleaded 95 / 98 -
Annual cost on E85 -

*Savings calculations take into account an average observed extra consumption of 20%.

From
€859 incl. VAT
Book an appointment

Why choose an E85 conversion kit?

Up to 50% savings at the pump

With E85 priced at around €0.83 per litre versus €2 for unleaded petrol, the price gap per litre is massive. Even taking into account the slight extra consumption linked to ethanol (around 25% with a kit), the savings remain very significant at each fill-up.

An eco-friendly fuel from French agriculture

E85 superethanol is produced in France from sugar beet, wheat and corn. It is a renewable fuel, locally manufactured, whose price depends very little on the price of crude oil. Driving on E85 also means supporting French agriculture.

Vehicle registration update with the "FE" marking

Installing a certified kit opens up the right to update your vehicle registration, with the addition of the "FE" (Flex-fuel Ethanol) marking. Your vehicle thus becomes officially recognised as flex fuel by the administration. This procedure is carried out directly on the French ANTS website, at the owner's expense.

A reversible solution

Unlike other conversion methods, the ethanol kit is physically removable. If you wish to return to the original configuration, simply have it removed at your centre. This is an important argument for motorists who value the ability to restore their vehicle to its initial state.

Ethanol kit and direct injection

One of the most frequent questions we receive concerns kit compatibility with direct injection engines (GDI, TSI, TFSI, EcoBoost, THP, etc.).

Currently, FlexFuel and eFlexFuel kits work mainly on indirect injection engines (classic multipoint injection). On direct injection engines, the compatibility scope is more restricted and depends on the exact model, the engine and the ECU in place.

If your vehicle is equipped with a direct injection engine, two possibilities:

  1. Kit compatibility check: depending on the model, FlexFuel or eFlexFuel sometimes offer a dedicated version. Our technician checks this during the preliminary diagnostic.

  2. Ethanol remapping: on the vast majority of direct injection engines, ethanol remapping is the most reliable and best-performing solution, as it acts directly on the original mapping. RS-TRONIC offers this alternative throughout its network.

Discover our ethanol remapping solution

Is my vehicle compatible?

The vast majority of petrol vehicles on European roads can receive an E85 conversion kit, provided they meet a few criteria:

  • Petrol vehicle (not diesel)
  • Generally registered after 2001
  • Minimum Euro 3 emissions standard
  • Compatible injection type (to be checked on a case-by-case basis for direct injection)

Each kit brand (FlexFuel, eFlexFuel) publishes its own vehicle compatibility list. Our technician checks your vehicle's eligibility at the time of booking, then confirms final compatibility during the preliminary diagnostic before installation.

Check your car's compatibility

Steps to install an E85 kit at RS-TRONIC

01

Diagnostic and compatibility check

Before any installation, our technician performs a complete vehicle diagnostic: checking the engine's condition, verifying model compatibility with FlexFuel or eFlexFuel kits, reading any fault codes. This step guarantees a smooth installation.
02

Installation of the certified kit

The kit is then installed in the engine compartment, connected to the injector connectors and wired to the battery. No mechanical parts are modified, no cutting is required. Installation takes on average half a day.
03

Configuration and road testing

Once the kit is in place, the technician proceeds with configuration according to your engine's specifics, then carries out a full road test to check proper operation at all loads and temperatures. Any necessary adjustments are made on site.
04

Vehicle registration update

Installing a certified kit then allows you to request the update of your vehicle registration with the addition of the "FE" marking. In France, this procedure is carried out directly on the ANTS website and remains the responsibility of the vehicle owner. In other European countries, similar procedures apply through the local registration authorities. Our technician provides you with the official installation certificate required for this procedure.

A 4-step intervention, carried out by an RS-TRONIC expert

Every ethanol conversion is carried out in an approved centre, by a technician trained and certified by RS-TRONIC. From kit installation to road testing, nothing is left to chance.

Get your vehicle remapped

The RS-TRONIC network: kit installers near you

Over 80 RS-TRONIC installers are spread across France to support you with the installation of your E85 conversion kit. Every dealer is selected, trained and approved to install FlexFuel and eFlexFuel in the proper way. You can therefore find a certified ethanol kit installer near you, without having to travel kilometres or wait weeks for an appointment.

Find a centre near you

FAQ

Frequently asked questions

Yes. Once the kit is installed, your vehicle officially becomes flex fuel: it can accept E85, unleaded petrol, or a mix of the two in any proportion. The kit automatically adapts at every start-up according to the fuel present in the tank, with no intervention required on your part.

E85 conversion with a certified kit starts from €859 incl. VAT, kit and installation included. The final price varies depending on your vehicle model and the chosen kit brand (FlexFuel or eFlexFuel). Note that regional subsidies of up to €500 may significantly reduce your final cost.

Yes, after installing a certified kit, you must update your vehicle registration to add the "FE" (Flex-fuel Ethanol) marking. In France, this procedure is carried out directly online on the ANTS website and remains the responsibility of the vehicle owner. In other European countries, similar procedures apply through the local registration authorities. Your RS-TRONIC installer provides you with the official installation certificate required for this procedure.

RS-TRONIC installs kits from two brands officially certified in France: FlexFuel (from Flexfuel Company) and eFlexFuel. Both manufacturers cover a very wide range of vehicles and are recognised for the quality and reliability of their products. Our technician recommends the brand best suited to your vehicle during the preliminary diagnostic.

Yes. The E85 conversion kit is a physically removable component. At any time, your installer can remove it to restore the vehicle to its original configuration.