Audi "recommends" using 91 octane gas but "requires" using no less than 87 octane. Will using 87 octane on a regular basis harm my vehicle?

125

Asked by May 24, 2013 at 09:24 AM about the 2013 Audi S4 3.0T Quattro Premium Plus

Question type: General

Audi "recommends" using 91 octane gas but "requires" using no less than 87 octane. Will using 87 octane on a regular basis harm my vehicle? From what I understand, today's hi-tech cars are designed to compensate or automatically adjust to lower octane unleaded gas so as to avoid "knocking" or "pinging". Is it just a waste of money to pay for "premium" octane gas?

14 Answers

655

What year is your Audi? - Audi recommends the higher octane for two reasons: It is refined cleaner, which means it does not gum up the lines, and burns cleaner in the engine allowing longer periods between oil changes, and the second is performance. Higher Octane means more energy in each combustion cycle. You may not notice a difference, but the engine will run more effeciently on a higher octane. Plus, when you break it down, if you put 10 gallons a fuel in, you're paying just a $1.00 more per fill up. This trouble is much better than dealing with a clogged fuel pump. I say suck it up and eat the $1.00 per fill-up and enjoy the greatness that is Audi.

9 out of 9 people think this is helpful.
107,355

The specs on some cars says premium (suggested). Looking at the specs on yours it states premium (required). I would only use the premium in your car. After looking at the specs on your car I just might have to go take one for a ride. 3 L V6 Supercharger AWD. Bet that's fun to drive.

4 out of 4 people think this is helpful.
88,765

Believe it or not but there are still some places that do not have premium fuel at the pump, it is that reason they put the "no less than 87" there as it is the bare minimum you can run. It is designed to use the expensive stuff so don't scrimp on the fuel you will pay for it in the long run. I would keep a bottle of 104 octane booster in the trunk just in case you do get a bad batch of fuel.

1 out of 1 people think this is helpful.
94,895

Buy the premium fuel. It delivers better performance and fuel economy for a few cents more per gallon. The S4 is a beautiful car with a high tech engine. Treat it right. --- See what other owners are saying on Audiworld.com and Audizine.com

3 out of 3 people think this is helpful.
40

The comment that higher octane means more energy in each combustion cycle is a common misperception. Octane has nothing to do with the energy contained in a said amount of fuel. The octane rating is a way of rating the fuels resistance to premature detonation or what is better known as "knock". The reason for the higher octane requirement is so that the engine can obtain it's maximum performance as designed. Most engines today have "knock" sensors which detect lower octane rated fuel and decrease engine timing to compensate. Reduction in engine timing normally results in slightly lower engine output and a reduction in gas mileage.

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Best Answer
125

All other factors remaining equal, using a higher octane fuel should result in better gas mileage, but not necessarily better "performance".

5

Evidently you guys have not done your research. Putting higher octane in your car does nothing but make the oil companies richer. It won't make your car perform better, won't make your engine run better, doesn't give better gas mileage, and IS NOT better for the environment. Higher octane actually hurts the environment more than it helps it: https://www.youtube.com/watch?v=FPPkPAbzwbU I drive an Audi S6. Never put in anything other than 87. Had it for 3 years, no problems. I save over $12 per fillup.

88,765

It all depends on the vehicle Joon. I have 2 late model vehicles, 1 states that regular unleaded fuel is recommended and the other states using premium fuel, so as an experiment I ran premium in the vehicle that recommended regular fuel and regular fuel in the vehicle that recommended premium fuel, the results were the premium vehicle almost instantly lost 4 MPG and performance dropped quite noticeably, the other vehicle had no noticeable change in performance and only got a .5 increase in MPG. So my real time experience tells me that to stick with what is recommended for fuel octane rating to get the best MPG and performance. If it says use regular fuel then run regular, if it says use premium then run premium. Your vehicles engine will like it and in the long run you will save money in maintenance costs.

5

I disagree. As does all the research done on this topic. Unless you're dragracing on the street, or trying to beat out the next lane at a stoplight, you're not going to see so much of a decrease in performance. Most people drive to work and back home every day, so at a constant speed you won't see that difference in performance. Sorry but I disagree. And most people don't ruin their engines by using the wrong octane. They ruin their engines by the way they drive.

88,765

Don't believe the research, believe the actuality of live tests. So I have to disagree with your findings as mine prove otherwise. So I will continue to use premium in the car that recommends premium and regular in the vehicle that recommends regular. And I don't know where you got the idea that using wrong octane will ruin a late model engines. Unlike the old days when high compression engines required premium fuels or you could blow a hole right through a piston.

125

tennisshoes...I appreciate your response. So just to be clear, you're saying that I can safely use regular (87 octane) in my S4 without fear of any damage to the engine...even though Audi "recommends" premium. Practically speaking, what is the "downside" to using regular over premium? Or conversely, what "advantage" is there to using premium over regular? Is it performance, fuel economy or what???

88,765

As I stated, it depends on vehicle, try an experiment, run your tank down to 1/4 and fill it with regular and carefully monitor the way it performs and your fuel mileage through 3 tanks of regular fuel, then do the same thing with premium, then compare the two, if the premium gives you more significantly more MPG then regular then stay with that, if not then go with regular or even a blend if your still undecided. Late model vehicles engine management systems will detect slight engine ping and adjust timing automatically to reduce it so you won't blow anything running regular fuel. In the testing I did on both my rigs it clearly showed me what fuels I needed to run in each vehicle to get the most out of the vehicles power plant. HTH

1 out of 1 people think this is helpful.
125

Thanks!

1 out of 1 people think this is helpful.
125

Premium gas vs. regular: What's really better for your car? https://www.youtube.com/watch?v=FPPkPAbzwbU Should I use hi octane premium petrol, and what is octane rating? https://www.youtube.com/watch?v=WYlk9C1o0nk

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