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Author	Topic: Which gas for a 2.8 Quattro A4?	Topic is locked Back to Topics

ak8b Sophomore Author Akron Posts:112 Points:861,940 Joined:Sep 2005	Message Posted: Jun 23, 2006 7:51:50 PM Ignore ak8b Report Abuse I recently acquired a 1999 A4 with the 2.8 V6 and Tiptronic Automatic. I really love the car but I'm still not sure if I should use "Plus" or "Premium". The dealer said it would be fine with "Plus" but I wonder. Most of my driving is short hop so I don't expect great mileage for that. For my type of driving what is best? If I'm going on a long trip would the choice change? I get in the 20-23 MPG around town and have gotten as high as 30 MPG on long trips.

ak8b

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Akron

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Message Posted: Jun 23, 2006 7:51:50 PM

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I recently acquired a 1999 A4 with the 2.8 V6 and Tiptronic Automatic. I really love the car but I'm still not sure if I should use "Plus" or "Premium". The dealer said it would be fine with "Plus" but I wonder. Most of my driving is short hop so I don't expect great mileage for that. For my type of driving what is best? If I'm going on a long trip would the choice change? I get in the 20-23 MPG around town and have gotten as high as 30 MPG on long trips.

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ak8b Sophomore Author Akron Posts:112 Points:861,940 Joined:Sep 2005	Message Posted: Nov 24, 2007 12:24:04 PM Ignore ak8b Report Abuse Sorry I haven't been paying attention here. Thanks all for the ideas and suggestions. You've convinced me that premium isn't really a requirement and my own experience has pretty much confirmed this. When I buy Shell (the only top-tier dealer in my market area) I buy Mid grade. When I buy BP or Marathon I will also go with Mid grade mostly except when I happen to buy at the local Marathon on Tuesday's which is 8 cents off premium day. Anything else (like at Sam's Club) I always get premium. I try to make sure that Shell or Marathon make up at least half of my fill ups.
NightMagic Champion Author Cincinnati Posts:57,105 Points:2,412,410 Joined:Sep 2006	Message Posted: Oct 14, 2007 9:19:39 PM Ignore NightMagic Report Abuse I have a 1998 A4 2.8 V6 Tiptronic Automatic which I bought new. The first tank of gas I used was regular and worked fine. I tried premium on the second tank (both cases let the gas light come on on the onboard trip computer display, <25 miles left), and got less MPG by about 2, saw no improvement in performance, and even detected a little hesitation. Same driving on both tanks, 90% to and from work. Since then I have used nothing but regular gas, and have had no problems. I have almost 100,000 miles on the car now and figure I have saved about $1000 in the price difference between the grades; and about another $1500 if the MPG drop was not a fluke, over the life of the car so far. Just my experience; yours may vary. I get about 18-20 City only, 21-24 Mixed, 26-28 Long Highway.
Cal Kidd Sophomore Author Toronto Posts:103 Points:4,200 Joined:Jan 2005	Message Posted: Oct 13, 2007 9:59:17 PM Ignore Cal Kidd Report Abuse I had the '96 A4 Quattro 2.8. My mechanic told me to always use the Premium otherwise the additional carbon build-up would require more frequent tune-ups.
s6sputnik Champion Author Austin Posts:6,222 Points:1,307,380 Joined:Jun 2007	Message Posted: Jul 22, 2007 6:21:40 AM Ignore s6sputnik Report Abuse So Iwonder what ak8b ended up using in his car?
GOLFDZLMK4 All-Star Author Nebraska Posts:645 Points:68,045 Joined:May 2007	Message Posted: Jul 22, 2007 5:37:37 AM Ignore GOLFDZLMK4 Report Abuse PREMIUM ONLY for my A4. That is what the owners manual calls for.
Mrtiger Champion Author Chicago Posts:8,070 Points:1,578,950 Joined:Sep 2006	Message Posted: Oct 20, 2006 2:16:00 PM Ignore Mrtiger Report Abuse Midium grade
#12#_rollsroyce1999 Rookie Author Akron Posts:2 Points:140 Joined:Sep 2006	Message Posted: Sep 6, 2006 10:55:01 AM Ignore #12#_rollsroyce1999 Report Abuse The need for higher octance gasoline is due to the detonation nature of your engine. This is primarily determined by the compression ratio. The higher the compression ratio, the more the gas-air mixture is compressed before the spark plug ignites the mixture. Higher octane fuels are more resistant to premature detonation basically meaning they can handle more heat before exploding. When you compress a gas it heats up; therefore the higher your compression ratio the more the air heats up and the higher the chances for premature detonation. I've read some different numbers for the compression ratio of that engine and I've heard numbers ranging from 10.3 to 10.6 but all of them are in a range that would definetely govern using 91 for normal driving. So, during normal cruising on a highway you will see no difference using 93 over 87. However, when you are going up a hill or accelerating you may hear "pinging". This is detonation and it is not good. It is not nearly as dangerous on a naturally aspirated engine as it is on a turbo or supercharged car but it is still not good. New engines (like yours) have knock sensors which look for a vibration in the engine caused by this detonation. When this happens the ECU typically retards the ignition to help stop the detonation. Unfortunately, the knock-sensor can only help stop knock AFTER it has already happened. To answer your question you can run whatever you want but if you are running anything under 91 you better keep your foot out of it. I have an '00 S4 and have run 89 numerous times on long (highway-only) sections of trips) If it was me I would us 89 on the highway sections and if you are adding to half of a tank of 91 or higher I would even top it off with 87. THis is only for highway trips. Otherwise stick to 91 or higher. Hope this helps. [Edited by: rollsroyce1999 at 9/6/2006 1:56:29 PM EST]
quattro02 Champion Author Twin Cities Posts:2,514 Points:192,185 Joined:Nov 2003	Message Posted: Sep 6, 2006 10:14:10 AM Ignore quattro02 Report Abuse I owned a '99 A4 quattro 2.8 liter for 3 1/2 years, but with the 5-speed manual. Premium is recommended and I never rally tried anything but premium. I learned with this car that our buddies at Super America have crappy premium (maybe all fuels, I don't know). This car used to stumble and bog at low rpm on SA premium, but ran absolutley fine on Holiday, BP, Shell, Phillips. The best I ever did with this car was about 27.5 mpg. That was a trip from Chicago to Minneapolis where I filled up about a block off the interstate, set the cruise for less than five over the limit (Wisconsin troopers love contributors with Minnesota plates) and drove until it was time to fill again.
ak8b Sophomore Author Akron Posts:112 Points:861,940 Joined:Sep 2005	Message Posted: Jul 14, 2006 5:08:35 PM Ignore ak8b Report Abuse Well, this has been a waste of time. Nobody seems to be able to offer an intelligent response. Nothing said here has provided any new information. Guess this will be my last post to THIS forum.
Ertman Sophomore Author Georgia Posts:152 Points:84,380 Joined:Sep 2005	Message Posted: Jul 14, 2006 7:03:47 AM Ignore Ertman Report Abuse Open the fuel fill flap, there is a sticker on the inside that shows yuo the recommended octane levels. Audiworld forums are full of information about your vehicle. Lower than recommended octane will result in knocking and pinging during acceleration. The car's ecu will compensate for it by retarding the timing. That will result in poor fuel economy. [Edited by: Ertman at 7/14/2006 10:06:15 AM EST]
SRSEN1999 Champion Author Phoenix Posts:1,530 Points:157,710 Joined:May 2005	Message Posted: Jul 2, 2006 8:00:05 PM Ignore SRSEN1999 Report Abuse I believe that Audi requires a premium fuel, so I guess anything that's above 91 Octane.
ak8b Sophomore Author Akron Posts:112 Points:861,940 Joined:Sep 2005	Message Posted: Jun 30, 2006 1:16:08 PM Ignore ak8b Report Abuse I know that's what is recommended. Is it needed though? What are the tradeoffs?
WTM Champion Author Philadelphia Posts:5,505 Points:958,850 Joined:Apr 2006	Message Posted: Jun 28, 2006 1:42:32 PM Ignore WTM Report Abuse I believe 91 octane is what's recommended by Audi.