I recently purchased a 2001 A6 2.8, and according to my owner's manual I should be putting premium gas into this engine. At this point I've filled the car up twice with regular gas (before I read this line in my manual).

Is premium necessary? The manual does say it has a 10.3 : 1 compression ratio. This does sound a little high for regular gas.

What kind of fuel are those of you with the 2.8 running?

 

Every audi engine should be running a minumum of 91 octane to get optimum performance and gas mileage out of the engine, but its not absolutely needed. If a german engineer that built the engine told me to run premium i would follow his recommendation.

 

As taken from my 2000 A6 2.8l V6 manual...The recommended gasoline octane rating for your vehicle is 91 aki / 95 ron. Do not use any fuel with octane ratings lower than 87 aki / 91 ron otherwise expensive engine damage will occur. Your vehicle may also be operated by using unleaded regular gasoline with a minimum octane rating of 87 aki / 91 ron. However, using 87 aki / 91 ron octane fuel will lead to a certain loss of engine power.

So if you have the 2.8l v6, go ahead and use 87, the manual says the only thing that will happen is you will loose some power and gas milage.

I notice I get about 2mpg better while using 89 vs 87 and no mpg gain using 91 vs 89. Individual results may vary.

Jeff

edit: look here: http://www.passatworld.com/forums/sh...d.php?t=239687

 

I only use Premium and I try to stick with a Top Tier/Audi approved supplier, such as Shell.

 

If you don't hear any engine knock using 87 octane, then you're fine. However, if you get any engine knock, then move up the chain to 89 and then 91 or higher, if needed.

 

As long as you don't hear any engine knock, then 87 octane is fine. However, if you hear engine knock, then move up the chain to 89 or 91 as needed to stop the knock.

 

internal combustion engines, particularly those fit installed to minimize engine noise, can experience a LOT of detonation without audible noise. The loss of power comes from a signal from a fairly sensitive knock sensor, that results in the ECU pulling ignition timing to try to reduce the knock. Its a safety factor for the unlikely event that fuel iwth the correct octane isn't available. The Bosch ECU is adaptive, so if low grade fuel is used over the long haul, there will be additional degradation of performance and economy as the ECU tries to change parameters to compensate.

 

I see what everybody is saying here but, if the manual says 91 octane minimum then follow it. Even if it's only a 2.8, it's still an audi. why wait for something to happen? I know gas is expensive but, audi engineers would not put 91 there if it's not required. It does say 91 minimumrequirement, right? And plus, you get better mileage with higher octane. i don't even put 91 on mine. Mine's always been 93.

 

Interesting economic experiment. It actually is cheaper to use 89 octane versus 87 octane in an A6C6 because of the 2 mpg increase. I now filled with 93 octane (that's the next step around here) and see if I get an mpg increase. I expect not based on anecdotal info I hear from others.

 

Every time I respond to this question, I get accused of being a cheap bastard. I've run midrange (89) gas for two years with no issues. I had the plugs pulled recently and even with 60k miles they were fine and did not need replacement. The 2.7T engine is 9.something:1 compression, which is less than either the 2.8/3.0l or 4.2l. I tried three consecutive tanks of premium and found no difference in performance nor gas mileage. Maybe, if I was running it real hard or at it's top speed, the higher octane might make a difference.

And I don't drink Starbucks coffee. I go with cheapcoffee from Speedway gas stations. However, I do prefer (and drink) Guiness over Miller Lite. It doesn't help my performance, but it tastes better.