Does fuel grade matter?

[j4sharks]

I am a new Q5 3.0 owner. Does it really matter is I use 91 vs 89 octane fuel in my Q5?

[TJay74]

I would run what the owners manual or inside of the fuel door says to run if it was me.

[711wildcat]

Short answer, IMO, yes. I wouldn't compromise performance and overall fuel economy for about $0.15/gal...but that's just me.

[goblues38]

short answer = no fuel grade does not matter

long answer = it is complicated

any "modern" car can run on any fuel at any pump. 87-94 octane. The car monitors each spark and constantly adjust timing for the most power and exhaust cleanliness.

So, if you use cheap fuel, the car will sense knock and retard timing to stop the knock. Knock or predetonation is what harms a motor. but when you have to retard timing you lose power. suddenly your 300 hp motor is only putting out 260 hp. The loss of power can cause the motor to have to rev hiring to make up for it. So saving .30 cents a gallon on 87 versus 93 octane may end up costing you more money in lost fuel economy.

Also, many gas companies put more / better additives in the high octane fuel that will keep you motor cleaner on the inside.

all that being said. Here is what I do.

I always put 93 octane in my cars unless I am on super ling road trips that will run out a tank of gas in one stint. Like when I drive from STL to Orlando. 1000 miles on the highway @ 75mph means I need no extra performance and just need the car to loaf along. The gas with no additives will not have a chance to sit around because the motor will constantly be hot and moving deposits out.

[q5 dave]

I am a new Q5 3.0 owner. Does it really matter is I use 91 vs 89 octane fuel in my Q5?

a premium car deserves premium fuel....

[bmoreS4]

a premium car deserves premium fuel....

100%

If you can't afford the extra change to use 93 instead of 89/91 then maybe you shouldn't have bought an Q5 with a SC engine.

[goblues38]

100%

If you can't afford the extra change to use 93 instead of 89/91 then maybe you shouldn't have bought an Q5 with a SC engine.

that is a little harsh. And not 100% accurate. As I said above, there are a few times when 87 octane is the correct choice for the application. Most cases it is not though.

[q5 dave]

that is a little harsh. And not 100% accurate. As I said above, there are a few times when 87 octane is the correct choice for the application. Most cases it is not though.

What does it say inside the fuel door and owners manual? "Premium fuel only"

California already has bad fuel, not sure why one would want to put in anything but the best available. Also it would only save $4 or $5 per fill up...


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[j4sharks]

OK, I can see we have borderline personalities on this board! It's not a matter of being cheap. There is a lot of scientific literature suggestive of the fact that there is no genuine value in the higher octane fuels given how they are formulated and how modern engines operate. In other words, suggestive that it's a lot of oil company "hype." Just curious what the experience of Audi Q5 owners has been.

[bmoreS4]

Next study....

Synthetic oil no better then regular oil.


I'll stick to the premium Audi calls for.

[crazyquik22023]

Next study....

Synthetic oil no better then regular oil.


I'll stick to the premium Audi calls for.

That is not even a close comparison. I agree that there is no need for premium especially when the situation doesn't call for it.

[Wilbur]

What does it say inside the fuel door and owners manual? "Premium fuel only"

California already has bad fuel, not sure why one would want to put in anything but the best available. Also it would only save $4 or $5 per fill up...


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higher octane isnt "better"...it has higher octane. If owners manual calls for 91 then 93 is a waste of money as performance will not change. As mentioned earlier, using lower octane will change performance but only marginally. Like others have said, go with what manual says. I believe when they say Premium they mean 91?

[q5 dave]

I want to maximize performance and efficiency in my Audi's so I only use top tier fuel, most often Shell v-power (93 octane).

As an Audi owner, you appreciate the exceptional performance of
one of the world’s finest automobiles. One way to help maintain that
performance is to use only an Audi approved gasoline. By fueling with
gasoline from a TOP TIER retailer, you help to ensure that your Audi
will deliver all the performance it was designed to provide.
Lower quality fuels can build up deposits in your engine, which may
degrade engine performance and vehicle emissions.

https://www.audiusa.com/content/dam/...l-Brochure.pdf


sure, you can put in cheap fuel. but it DOES matter.

[colby7]

If you get your Q5 tuned, and want to drive it spiritedly, then it absolutely matters.