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Types Of Gas An Audi A5 Takes (Explained)

Types Of Gas An Audi A5 Takes (Explained)

The Audi A5 has been in a class of its own. With coupe and sportback body styles, it has attracted a lot of buyers. Starting at $40,000 – $50,000, it has a premium price tag, and why not? It’s an Audi, after all. 

Today, we want to look deeper at the A5 for its fuel-related topics to see how it fares as a daily driver.

So, what types of gas does an Audi A5 take?

All generations of the Audi A5 have premium unleaded gasoline with an octane rating of 91 recommended for optimum performance, especially if you want to achieve the rated horsepower numbers. However, regular 87-octane gasoline can temporarily be used when premium gasoline is unavailable. Audi also strongly advises against using additives in your A5.

So, the engine of the A5 takes anything above 87 octane for fuel as per the manual. And like most Audi vehicles, premium is the preferred fuel.

However, that certainly doesn’t tell the whole story. Below, we’ll look at all the different engine types and what type of gasoline fits best there.

Furthermore, there are various types of fuels and additives you can and can’t use, which we’ll also discuss. Read on!

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Infographic on the fuel types for a Audi A5.

Does The Audi A5 Require Premium Gasoline?

2016 – Present

The current Audi A5, the 2nd generation, has a 2.0-liter displacement and a 4-cylinder engine. For the fuel type to be used with this engine, Audi suggests a minimum octane grade of 87.

87 octane, 89 octane and 91 octane fuel levels explained

However, Audi suggests that if one wants to achieve the rated horsepower numbers, it is better to opt for higher octane-grade fuels like premium gasoline with a 91-octane rating. That’s true not only for the A5, but also for most other Audi vehicles including the similar-sized A7 and the larger Q5.

EngineFuel Requirement 
2.0-liter 4-cylinder87-octane minimum, 91 recommended


2007 was when the 1st generation of Audi A5 was launched. It remained around until 2016 before being replaced by the 2nd generation A5. The 1st generation was offered with two engine displacements. One was the 2.0-liter base variant, while the other was a 3.2-liter 6-cylinder engine.

As per the owner’s manual for 1st generation A5, Audi suggests that car owners use at least 87 octane-grade fuel. However, 91 is recommended.

EngineFuel Requirement 
3.2-liter 6-cylinder87-octane minimum, 91 recommended
2.0-liter 4-cylinder87-octane minimum, 91 recommended

If you’re interested in the different gasoline requirements for all Audis, please read the article we just linked.

What Types Of Gasoline Can And Can’t Be Used?

In the market today, various types of fuels available serve different purposes. Let us look at some of the options and see whether or not these are a good fit for the Audi A5’s 1st and 2nd generation.

Reformulated Gasoline

Environmental conditions have motivated engineers to develop greener and cleaner-burning fuels. Reformulated gasoline is one such type of fuel that is highly environmentally friendly. It allows for lower emissions of harmful gases into the environment, making our planet a safer place environmentally by burning clean and green.

Given the environment-friendliness of RFG, one might expect some suggestions from Audi. But Audi remains neutral by neither suggesting for nor against using RFG. However, from experience, we know that carmakers recommend reformulated gasoline whenever possible.

Audi, as we’ve also mentioned in the Audi A3 fuel type or the Audi A6 fuel type, even the Audi Q3, doesn’t explicitly recommend reformulated gasoline in the owner’s manuals because it’s a German brand, and RFG doesn’t exist in Europe.

Gasoline/Oxygenated Blends Or E-85 

Audi also takes the use of ethanol seriously for their cars. As per the owner’s manual of the Audi A5, ethanol-blended fuels may be used for the Audi A5, but to do so, one must ensure that the ethanol blend should not exceed 10% for the first generation or 15% for the second generation. The remaining 85% is gasoline, with an octane rating of 87 or above.

Ethanol levels for cars explained, E10, E15 and E85


Many high-performance vehicles use ethanol-blended fuels for their cars. A very common type of ethanol-blended gasoline is E-85. The 85 in E-85 denotes 85% ethanol blended with 15% regular gasoline. It is a very high ethanol concentration blend, and a vehicle needs to be E-85 compatible to use it.

In the case of the Audi A5, only some first-generation engines are compatible with FlexFuel (E85).

Manufacturers leave different indications or markings of a vehicle’s E-85 compatibility. A common one of these indications is a Flex-Fuel badge found on your vehicle. The other indication is the E-85 marking on the vehicle’s fuel cap. If either of these is available, your vehicle is E-85 compatible.

While using ethanol-blended fuels, some symptoms and precautions become mandatory. The precautions one needs to ensure are:

  • 11 liters minimum of fuel should be filled at the time of refueling
  • After refueling, the vehicle should be kept running for at least 7 miles or more

The symptoms linked with the use of E-85 fuel are also attention-worthy. These are:

  • Hard starting and unsmooth idling
  • Residue build-up and possible corrosion due to deposit formation

Gasoline With Added Materials

Gasoline may be added with different materials for different purposes. Some additives are cleaning agents, and some are detergents available today at various gas stations.

However, it’s good to know that Audi strongly advises against using additives in your A5. This is because these additives can contain materials such as silicon or metallics that will seriously damage the engine and the fuel system.

Therefore, it’s recommended that you buy fuel that already has all the proper additives mixed into it. This kind of fuel can be purchased at certified TOP TIER gasoline retailers. These retailers sell gasoline that will provide the optimal performance for your engine and clean it as well as possible without damaging it. You can find a retailer at

Gasoline With MMT

MMT is an octane enhancer that is added to gasoline. Methylcyclopentadienyl Manganese Tricarbonyl, at the time of its introduction, was sold as a supplement, but later on, it was marketed as an octane enhancer. MTBE is also another type of octane enhancer that is available today.

The Audi A5 2nd generation’s owner’s manual doesn’t state anything about gasoline use with MMT or MTBE. But the 1st generation’s manual states that the below points need to be ensured in case one wants to use gasoline with MTBE:

  • Gasoline with a minimum octane grade of 87 AKI should be used
  • MTBE blend should not be more than 15%

What If I Hear A Knocking Noise From The Engine After Refilling?

Usually, knocking sounds may be heard from the engine if lower-grade octane fuels are used. For instance, as Audi recommends a minimum of 87 octane grade rating, engine knocking is likely to use such a low octane grade. It is relatively typical as almost every driver has experienced this knocking sound.

A quick fix to this issue is to use higher-octane-grade gasoline. We suggest a minimum of 91. There is a great chance this knocking sound can be eliminated by switching to a higher-grade octane fuel. However, there is still a chance that the engine knocking may not stop.

However, if you hear loud engine knocking, it´s best to stop the car immediately and call your dealer. Most likely, your car needs to be drained of its fuel, and the fuel filter will need to be replaced.

Does The Audi A5 Have Good Gas Mileage?

Given that the A5 is an Audi, you would expect the fuel economy to be quite bad. However, the Audi A5 has quite a good fuel economy, especially the second generation, because this generation is a mild-hybrid electric vehicle.

2016 – Present

black 2018 audi a5 sportsback parked in front of house
EngineCombined MPGCity MPGHighway MPG
2.0-liter Inline Four272431

2007 – 2016

white 2013 audi a5 parked in front of dealership
EngineCombined MPGCity MPGHighway MPG
3.2-liter 6-cylinder201627
2.0-liter 4-cylinder262232
2.0-liter 4-cylinder (E85)181522

What’s The Gas Tank Size Of An Audi A5?

The fuel tank capacity of one’s car determines how far one can go without worrying about a fill-up. The current generation of Audi A5 has a tank capacity of 15.3 gallons. Given its fuel average, it has 300 miles or more before one needs to worry about a fill-up.

The first generation of the Audi A5 had a 16.8 gallon fuel tank. With the average fuel economy that the 1st generation Audi A5 offers, it is safe to say that 300-plus miles can be achieved in one fuel tank.

GenerationGas Tank
2nd Generation15.3 Gal
1st Generation16.8 Gal

Closing Thoughts

While this information might be a lot to process it’s important to remember that the Audi A5, with its premium engineering, is designed to run optimally on premium unleaded gasoline with a 91 octane rating. While it can run temporarily on 87-octane gasoline, for peak performance and to reach the rated horsepower, premium gasoline is essential.

All in all, when it comes to maintenance, a luxury car like the Audi A5 involves more than just fuel considerations, but that doesn’t mean you shouldn’t have an understanding of the intricate details of each engine type and how they interact with different fuels, since it’s something that will ensure the longevity and performance of your A5.

If you’re interested in more fuel talk and if you’ve ever wondered about the effects of mixing different octane fuels, our article “Why Mixing Different Octane Gasoline May Destroy Your Car” sheds light on this common query.

Ultimately, the type of gasoline you use is a significant factor in your Audi A5’s performance, but it is just one piece of the larger maintenance puzzle. Remember to use the recommended octane level and avoid additives to keep your A5 running smoothly.

Happy driving!


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