timhayden

The owners manual recommends 91 octane but says and I quote "Your vehicle may also be operated using unleaded regular gasoline with a minimum octane rating of 87 AKI. However, using 87 AKI octane fuel will slightly reduce engine performance." No mention of any harm, just less performance, and my wife is more interested in saving money than stoplight racing. At $.20-.24
per gallon cheaper that's $4 per tank less which would be about $1000 saved over 100,000mi. Our Lexus RX330 owners manuel said the same thing and we only used regular in it, just trading it in after 105,000mi and not spending one penny on the engine. I have a twin turbo V8 Lotus Esprit and only use 91 in it, so you have to make a judgement call based on the car, engine and intended use.

FitzLA

I have been using 89, but if the prices go up again I will gladly switch to 87. But on that not, performance is not the only reason for using higher octane. It can have cleaning benefits to it as well. Although since I leased my car, I don't really care. LOL. I'll only have it for 3 years.

Cavalier

I would suggest doing a few tank fulls of higher octane and then testing your milage. Last year when gas was stupidly high and I noticed that the higher octane was only the usual .20 or .30 higher yet gas overall was nearly $4.00 per gallon. I switched to the higher octane.

I got like 2-3 more MPG. In those days of super high gas prices I actually SAVED money buying higher octane. The fact that the gas companies didn't adjust the variance in price more when gase prices increased shows what a scam the whole thing really is.

Anyway it just boils down to how exactly your car reacts to the better gas. If it is able to improve MPG with higher octane then you may still be able to at least break even using a higher octane.

BlackPrestige

Fitz, I leased mine too....so should I use 87, 89 or 91? I don't want to screw the engine up.

FitzLA

I can't really give you that advice. I know they recommend 91 or higher, but state that you can use 87 if you want. I stick to 89. I used 91 in my BMW 535i, but that was a performance car. This is more of a utility suv with some performance. I don't think 89 will mess with the engine. But I am not a professional so I can't really give you that advice.

BlackPrestige

I'll ask the dealer when I pick it up today

fe342185

The car I turned in last yr 2005 A6 3.2 liter had issues with the low octane. I too used 87 since it was a lease and 87 worked just fine for the 2002 A6 3.0 I leased prior.

Issue:
Upon hitting the gas from a full stop the engine would tick a few times. I ignored it and showed it to the dealer on the 5000 mile check up. They held the car for 2 weeks since there was one other person with the same issue. They said they crated both engines and sent it to germany since they could not determine the issue plus the 3.2 liter engine is new for 2005.

2 weeks later I got my car back with a new engine although they did not tell me what was wrong but I didnt care since I just wanted my car back. After i emptied the gas tank I put 87 in again and the ticking came back. I called the dealer and they said its impossible since its a new engine. They decided to research and call me back.

An hour later I get the call---- "Sir please stop putting regular in the car". Needless to say I was slightly embarassed for being able to afford a $55k car and skimping on the few cents for gas.

Lesson learned and after that I used 91 or 93 only when available.

On 93 I got 29.1mpg cruising down the NY Thruway driving at 76mph average. It was a 1.5 hour drive with only 1 passenger and ski gear. Not bad for a car that stated 21 city 26 highway. When I filled up, the computer has displayed 630 miles to empty which was great since the car had a 21 gallon tank.

My guess would be the higher octane can affect gas mileage as well as performance. At least thats what I told myself to justify the few cents extra per gallon.

Good luck.