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Frequently asked questions

Compatibility Faqs

Your vehicle can only burn E85 flex fuel if it is configured to do so. By installing one of our kits, your vehicle will become compatible with E85.

However, we do not offer our kits for all vehicles. To see if we have a kit for your vehicle, please use the year/make/model lookup tool on the home page.

NOTE: If we don’t have a kit for your vehicle, don’t give up! Let us know your vehice make/model/year and VIN and we will research it for you - go to Inquiry page and send us message.

Our kits can not be added to any diesel engine, any engine with a carburetor (most vehicles built before 1986 are carbureted), or engines that have a mechanical fuel injection system instead of an electronic fuel injection system (not common). Additionally, eFlexFuel products are not currently compatible with many direct injection engines.

Assuming you want more performance - and assuming the engine is modern enough to have electronic fuel injection - than the answer is yes. Flex fuel is a mix of ethanol (aka ethyl alcohol, which is what many dragsters and race cars run on) and gasoline. Because flex fuel contains a large proportion of alcohol, it is higher octane than gasoline. Higher octane fuels will make more horsepower with proper tuning.

So, if you want more power, you want to add one of our flex fuel conversion kits to your engine.

Read more about the performance aspects of flex fuel.

The answer is almost always yes. In fact, flex fuel and E85 usually generate even more power when used on a modified engine, whether that modification is something simple (like an exhaust or cold air intake) or more serious (like forced induction or aggressive cams).

However, if you have a modified engine, please contact us and describe your modifications so we can confirm that your vehicle will be compatible with one of our flex fuel conversion kits.

Product-Related FAQs

All eFlexFuel kits make your vehicle E85 flex fuel capable, meaning your vehicle can run on gasoline, E85, or any mixture of the two. Our kits are bolt-on, warrantied for 5 years, and easily removed if you decide you no longer want flex fuel capability (our kits do not make any permanent changes to your vehicle).

With our eFlexPlus, you’ll be able to both reduce your fuel expense and maximize your engine power. With multiple operating modes, eFlexPlus can be configured to maximize fuel efficiency or boost horsepower. Intended for racing or off-road use, the eFlexPlus kit is great for anyone trying to maximize engine power without becoming a professional tuner.

Finally, our eFlexPro kit is for serious performance enthusiasts. With the included tuning software and support for up to three custom tuning presets (in addition to 3 built-in presets), you’ll have total control over your vehicle’s fuel mapping. And our tuning software also features 3D fuel mapping capabilities that will make your vehicle faster around the course or down the strip. And the eFlexPro is also compatible with the app, so you’ll have detailed insights into engine performance in real time.

Best of all, whenever you install one of our flex fuel conversion kits, you’re helping the American farmer and decreasing your carbon footprint. Ethanol is produced from homegrown corn in the United States, and because it’s refined from corn it’s a renewable resource. Nothing wrong with any of that, right?

Our kits start at an MSRP of $550. But first, let’s make sure your vehicle is compatible with one of our kits - visit our year-make-model lookup tool to see what we have available for you!


Unless otherwise agreed in writing, the buyer will be charged applicable state and local sales taxes.

We’ll send you the right one ASAP. Call us at 833-539-3835, and we’ll start the process.

You will want to follow our Returns procedure. Please contact us to obtain a return authorization number and further shipping instructions. Please note: All returned items must be in new and unused condition, with all original tags and labels attached. To avoid this issue, we recommend using our Year-Make-Model lookup tool to ensure the product you ordered is compatible with your vehicle, located on the homepage at https://eflexfuel.com/us. If you are having difficulty finding a match for your engine, please contact eFlexFuel Support.

It depends on where you live in the United States. We test the , shipping generally takes about 3 days.

We provide installation guides and offer a step-by-step video library to assist you with installation right here.  You can also buy the kit installed from one of our installation shops or take it to a local shop for the installation. Expect them to charge 2-3 hours of labor for it. If you still have questions, please email us at [email protected].

You must notify eFlexFuel in writing within 30 calendar days from the date of delivery for any kit you wish to return or exchange. To return or exchange a product, send an email to [email protected], explaining the reason for the return/exchange request. Most requests will receive a return authorization number and further shipping instructions. After receiving the return authorization number, the items must be securely placed in its original packaging and include a copy of purchase receipt. Please be advised – we are charging a $100 restocking fee.

We’ll get you a replacement ASAP provided that a) you inform us immediately and b) you keep the damaged box so we can get our carrier to reimburse us.

eFlexFuel products are available in several regions around the globe. Please select the correct regional site to place your order if you are outside the United States.

Currently,  all of our products are available with free shipping and most often processed within 24 hours of receipt. You will receive an email with your DHL tracking number when your package is shipped. You can expect it in 2-4 days.

We currently offer Free Shipping on all eFlexFuel products through DHL. You will receive an email with your DHL tracking number when your package ships.

You will receive an email with your DHL tracking number when your package ships.

We accept American Express, Discover, MasterCard, Visa, and PayPal.

Our site is 2048-bit SSL secured, which means your personal and credit card information is encrypted to keep it safe. We do not store credit card information. Also, if you opt to pay with PayPal you receive their security protections.

Hurry! Contact us right away at 833-539-3835 because we strive to process orders and ship within 24 hours. Once a purchase has shipped, you’ll need to follow our return process-

No, an account is not required for purchase.

eFlexFuel guarantees its products are free of manufacturing defect for 2 years of use. If you wish to extend the limited liability warranty to 5 years, please register your product here.

Although it is possible, we don’t recommend attempting this without first contacting us. The team at [email protected] may be able to offer guidance, depending on your situation.

It’s actually against federal law to void a warranty for use of an aftermarket part. The Magnuson-Moss warranty act, enacted in 1975, makes it illegal for auto manufacturers to void a warranty simply because the owner of the vehicle adds an aftermarket product. The law states that unless the manufacturer can prove the problem was caused by an aftermarket part, they have to repair the vehicle.

Use our handy Year-Make-Model-Engine lookup to find a compatible product for your vehicle.  If your vehicle is listed as compatible, it means that our technical team has verified it’s components (i.e. fuel pump, fuel injectors, fuel lines etc.) are compatible with both E85 and eFlexFuel products. If your vehicle isn’t listed, please make a compatibility request with the “Can’t Find My Vehicle” button. If you’d like additional assistance, please contact us at [email protected].

Just call 833-539-3835 during regular business hours, and our customer support team will assist you.

10am – 5pm, EST, Monday through Friday.

On occasion. The best way to learn about any offers or promotions is to join our email list.


Probably yes, assuming you have some tools and some experience with automotive maintenance and repair. Installing one of our flex fuel conversion kits is about as difficult as replacing a fuel filter and installing an engine tuner. Most people need 2-3 hours to install an eFlexFuel kit, only more experienced DIY'ers can be done in an hour or less. Of course, installation difficulty varies from vehicle to vehicle.

As far as tools, you just need basic hand tools (screwdrivers, socket set, etc.) and a multimeter.

Every eFlexFuel shipment includes an installation manual. You can also find installation videos on our website here. If you have a question about installation or some sort of problem, our customer service team is available by email or phone during normal business hours. Just contact us.

If you’d rather not do the install yourself, expect to be charged for 2-3 hours of labor to have the kit installed. Any reputable shop should have no trouble with the install, and our customer service team is available to professional installers as well.

In most situations, the answer is no to all of the above. If you have a heavily modified vehicle, you may want to upgrade your injectors and/or your fuel pump, and in very rare situations you may even need to upgrade your fuel lines. However, 99% of the people who buy one of our kits do not need to modify their fuel system whatsoever (beyond installing our kit of course).

If you have questions about your vehicle, please don't hesitate to contact us. We have automotive engineers available to answer even the most complex questions, and to confirm compatibility.

Yes. When eFlexFuel is installed, no permanent changes are made to your vehicle. Removal of the system is fairly easy. Furthermore, we can provide a bypass module for short-term use.

However, because our kits make your vehicle Flex Fuel capable, there is usually no need to remove them. If for some reason you can't buy flex fuel, you can fill your tank with regular gasoline with no problems.

No. But if you are racing your vehicle and/or you would like to maximize engine power, be sure to check out our eFlexPro kit which includes professional engine tuning software, as well as the eFlexPlus, which offers tuning capabilities via the smartphone app.

Our eFlexPro kit includes engine tuning software that is Windows compatible only (sorry Apple fans).

But our eFlexPlus and eFlexPro have a mobile app that runs on any Android or iOS device, and that app has some built-in tunes that are great for the track or off-road.


E85 is over 100 octane, making it the most potent fuel available at the pump today. If your engine is turbocharged or supercharged and properly tuned, running E85 can boost power output as much as 20%.

For vehicles without a turbocharger or supercharger, the gains are more modest. Most people report a 5-10% improvement in horsepower, as well as better throttle response. Additionally, many of our customers have said that their engine runs noticeably cooler and smoother. More than one person has said “my car loves this stuff!”

If you’re running E85 in your engine without making any adjustments, then yes. Engines need tuning adjustments to burn E85 correctly.

But if you install one of our kits? E85 can not damage your engine - not even a little bit. But it’s a popular myth.

Back when ethanol was first added to gasoline (we're talking almost 30 years ago), there were some situations where engines were damaged. But almost all of these engines were either carbureted, used mechanical fuel injection, or were produced before 1994 when engines and fuel systems didn't have to be ethanol compatible.

But ever since 1994, it's been US federal law that vehicles are ethanol compatible. And, with one of our flex fuel conversion kits properly installed, you can rest assured your engine will not be damaged whatsoever if you choose to run E85 flex fuel. We’ve verified each and every vehicle application listed on our website to ensure it’s compatible with our kit.

NOTE: Our kit has been installed on more than 30,000 vehicles around the world - with more than half a billion miles driven so far - and we haven’t had one customer come back to us with a report of engine damage.

It depends on your vehicle and your vehicle manufacturer's recommendations.

By default, most manufacturers recommend a shorter oil change interval on vehicles that run E85 flex fuel. However, this is also true for vehicles that drive in extreme hot or cold, drive in stop-and-go traffic, or that are used to haul or tow on a regular basis. So, assuming you're already following the manufacturer's maintenance schedule for severe duty/severe use, your oil change interval won't be any different. Otherwise, you’ll want to adjust your maintenance schedule to whatever the manufacturer recommends for E85.

Finally, the eFlexFuel capability system itself is completely service-free and designed to last the lifetime of the vehicle. You do not need to do anything to maintain your eFlexFuel kit.

Yes. Most people who have installed our kit do not report trouble with cold start. But if you live in colder winter temperatures (less than 35°F) and you’re experiencing issues, we recommend taking the following steps:

  1. Use an engine block heater.
  2. Fill up with 10% or more gasoline to lower the ethanol content.
  3. Make sure that the engine is well maintained and, in particular, the ignition components and spark plugs are in normal working condition.

NOTE: For track or off-road situations where cold start is a concern, eFlexPlus and eFlexPro come with an adjustable cold start feature that is accessible from the eFlexApp smartphone application or eFlexTuner. This will allow you to configure the cold start specifically for your vehicle if needed.

eFlexFuel products are not road legal, so it is forbidden to use them in emission-controlled vehicles. From emissions point of view however, you would pass the tests with flying colors. Actually - with E85 and eFlexFuel products - vehicles emissions are significantly lower than with gasoline blends and without eFlexFuel. This is because when fuel injection is done right, E85 burns cleaner - and contains less harmful aromatic compounds - than gasoline.

E85 used with eFlexFuel also produces less secondary formation aerosols so it is better for the air quality too. This all results in cleaner emissions. In fact, this is precisely why our eFlexEco is pending CARB and EPA approval - all our testing done in EU and in USA shows that the eFlexEco reduces vehicle emissions.

We are currently working on California Air Resource Board (CARB) and Environmental Protection Agency (EPA) approvals for the eFlexEco kit. In Europe, we have passed all the strictest emission tests so we see no reason why would we not pass similar tests in the USA. At this point we don’t have a projected time frame yet for these approvals.

However, this only applies to eFlexEco because the eFlexPlus and eFlexPro are adjustable between our standard “Eco” driving mode and more aggressive driving modes. This is why we offer those kits for off-road or racing use only and do not intend to apply for CARB or EPA approval for them.


Absolutely! All eFlexFuel kits add flex fuel capability - they do not take any options away. You are free to fill your vehicle's fuel tank with E85 today, gasoline tomorrow, or a mix of both. This is because our kits make your vehicle a fully automatic flex-fuel system. Our eFlexFuel technology automatically adjusts the fuel map and engine timing to run optimally on any fuel blend.

Fuel economy is very hard to predict, but generally speaking most people see a decrease in fuel economy when running their vehicle on E85. The decrease may be just a few percentage points, or it may be as much as 25% - the specific amount is determined by the amount of ethanol in your fuel. People who mix gasoline and E85 are often able to reduce their fuel spending without reducing fuel economy, while people running E85 only report 15-25% lower fuel economy.

However, in situations where the fuel economy decreases 25%, most people still find that they spend less money on flex fuel than they would on regular gasoline. This is because flex fuels are significantly cheaper to buy than gasoline. And if you install any of our kits, you will have the option to tune your engine for the highest possible fuel economy .

Finally, it's important to note that E85 can have anywhere between 51% and 83% ethanol. Depending on the mixture, you may find that your vehicle gets nearly the same MPG running flex fuel as it does running regular gasoline.

NOTE: It is possible to mix gasoline and E85 to create your own optimal mixture. When the fuel is about 50% ethanol, most people report a very slight reduction in fuel economy and a substantial cost savings.

Almost always yes. In most places in the US, flex fuels like E85 are significantly cheaper than regular gasoline - anywhere between 20% and 40% less costly. So even if your vehicle gets fewer miles to the gallon burning flex fuel, you could still save money. Also, because E85 is always over 100 octane and clean burning, it's more comparable to premium or supreme gasoline than it is to regular gasoline in terms of performance and cleanliness.

Finally, if you really want to maximize your fuel savings, you can try mixing E85 and gasoline to achieve a mixture that's 50% ethanol and 50% gasoline. All of our kits will recognize the mixture and automatically adjust to maximize your vehicle’s fuel efficiency - you don’t have to do anything other than fill your tank.

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