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What is your GAS MPG?

 
Old 05-25-2011, 05:00 AM
  #11  
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Originally Posted by killerwatts View Post
I live in chicagoland area and our traffic is pretty bad but I average around 20-22 combined. I just drove to Maryland and I actually was getting 31 MPG as shown on display at one point. I do not doubt the accuracy of the display as it changes to match the conditions you are driving at such as high speed (MPG go down), Normal speed (MPG is best), Hills (MPG decrease) etc. I took a picture of my display showing me doing 70 MPH and the MPG display showing 31.0. at that point I had been driving steady and constant 65-70 based on traffic for awhile. I let my gas gauge reach the point whereby the display showed that I could go 5 more miles til empty. Based upon the amount of gas I put in at the fill-up I would say it was scary accurate. Now I do have high confidence that the numbers the display shows are quite accurate. As for the original poster's mileage dilemma he is getting decent mileage (and that is based on the conditions he may be encountering on a daily basis). But in all the suggestions such as spark plugs, air filter, oil (does make a difference) etc no one mentioned oxygen sensors. I have not replaced them in this A8L but have in my original A8 I replaced them as he result of a check engine light diagnosis which revealed a bad O2 sensor. He never stated if he had a check engine light on. I will post my display picture when I complete the return portion of my trip just in case I get something better. Also since I'm in the area I'm gonna drop by southern Electronics and see if they may be able to fix LED issue in cluster (that is only if they don't need a few days)
You REALLY should doubt the display...it is an illusion. Current mpg is meaningless...you can back off the gas and maintain speed for a ways and display will tell you 60-90mpg. Even for average mpg, the displays on these cars are almost NEVER correct.
Physics prevents these cars from getting 31mpg level highway average...impossible.
True mpg, as I've stated (as laws of physics state) can be determined accurately only ONE way:
Fill tank, reset odo, drive to and from a location (all highway), refill, do the math. Remember, acceleration to speed from the gas station is given back as you slow down to the next refill. This way gives you a true average highway mileage...the ONLY true mpg reading...a current display reading while driving means NOTHING, except is a good way to keep you're foot out of it when not needed.

At 31mpg, you could drive from interstate gas station to the next fill up 683 miles on 22 gallons (not bone dry)...right...dream on.

If ANYONE can INDEPENDENTLY document over 26mpg on a stock D2 in true LEVEL driving (coasting down a 31 mile hill doesn't count), not only does Audi and the EPA want to hear from you, I will drink the rest of your tank of gas and wash it down with your steering fluid

Last edited by silverd2; 05-25-2011 at 05:10 AM.
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Old 05-25-2011, 12:24 PM
  #12  
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14.3mpg
recoded transmission isn't going to help the cause
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Old 05-25-2011, 02:34 PM
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Converted cars that run on E85 loose around 25% mpg (compression too low to take advantage)
its not just a compression issue, Ethanol contains about 10% less energy per unit volume than gasoline does. so even if the engine were perfectly adapted, MPG would be 10% less.
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Old 05-25-2011, 04:34 PM
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Originally Posted by A8_novice View Post
Converted cars that run on E85 loose around 25% mpg (compression too low to take advantage)
its not just a compression issue, Ethanol contains about 10% less energy per unit volume than gasoline does. so even if the engine were perfectly adapted, MPG would be 10% less.
True, but I was referring to highly modified race engines running 15 to 1 and higher compression ratios, requiring alcohol fuel...NOT efficiently, though...just high powered due to high compression.
Alcohol has the advantage of being very resistant to pre-detonation and added cooling qualities...both conducive to burning correctly in ultra-high compression engines.
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Old 05-26-2011, 07:28 AM
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Default No one is going to believe my MPG

I have a 98 A8 and a 2000 A8L both with the 4.2

I live in a small touristy town in Michigan. The "city" driving consists mostly of 4 lane commercial type roads around malls, etc with traffic lights and some heavier traffic early morning and around 5:PM when factories let out. Residential areas surround the city out about 5-10 miles away. Some residential areas are closer in than my house with is 10 miles and connected via 2 lane with occasional traffic lights and frequent stop signs going into housing areas. An interstate connects thes town to a larger city which is about 25 miles away.

I drive the A8L about 15,000 miles/ yr, mostly local running around to stores, errands and stuff. This is about 60% of my driving . The other 40% which is once or twice a week, is on the interstate to the larger city. In MI the highway speed is 70 MPH. Once or twice a year, we go to another state to visit or take a vacation.

My wife normally drives the 99 and does about 8,000 miles per year and never goes on the interstate.

Trip computers are fairly accurate on both cars and checked against gallons, miles once a month or so. The results: (remember this is average)

99 A8 = 20 MPG
2000 A8L = 23 MPG

On an all highway trip in either car (me driving), I can squeeze close to 30 MPG. On either local roads or the highway, I do not drive slow. Trip average speeds are 60MPH or more which includes eating and pee stops.

Around town, I drive similarly, if the limit is 45, I'm probably doing 50, but starting from a light or stop signs other cars will zoom ahead of me. (I generally catch up to them or pass.) Yes, I pay attention to the lights ahead. Occasionally, I am able to run errands going through 10-15 intersections which have lights and never completely stop. (No, I don't go through them on red, I coast and slow as I approach them). The same goes for other cars making turns etc. If I am following at 8-10 car lengths, it allows me to anticipate what other drivers will do, often able to pass a turning car safely without slowing down.

I've driven like this for years on all my Audis and consistently average MPG results exceeding EPA estimates for highways, yet drive less that 1/2 on highways.

I am what the young guys would call a "slow starter". How fast you accelerate from a light, stop etc doesn't mean squat if you don't get to the destination any sooner than me. I prefer to think of myself as an "I'll get there at the same time you do". And do it without wearing out brakes or making OPEC any richer than I have to."
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Old 05-27-2011, 04:32 PM
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I would love to take you up on your gas drinking offer with the chaser!!!!!!! It sounds like you are looking at the instaneous miles per gallon display (there are 2 MPG displays). If you are seeing 60-90 MPG than I would say wholeheartedly doubt what you are seeing if you are looking at the correct display. Based on the distance I traveled I have no doubt that my MPG display is pretty accurate. I did not say I got 31 mpg the entire trip just for a timeframe (after fill up and for a good distance and yes it varied but I was able to get to 31 and it held at 70 MPH constant until conditions changed or I speed up again. I also stated it varies with conditions ranging from running AC to high speed, hills, stop and go,type of gas (I was using shell V-power case you are wondering) general maintenance etc. The display on my vehicle is pretty darn accurate and I have gotten well over 550 miles out of a tank of gas on highway driving while seriously fracturing the speed laws (got up to 120 while following a corvette)and even with the high speed chase which was still on my first tank leaving chicago and the varying speeds from corvette run to basically 70-75 miles MPH I did not do my first fill-up until about 45 miles from Maryland border on PA side at which my miles you can go on gas display showed me 5 miles left with current tank of gas (That's the point I found out how accurate the displays are). Based upon what I put in tank I don't doubt my car. Mine is doing what it's capable of doing or exceeding accordingly. In either case it is what it is and I was not looking at insant mpg which is all over the place from one second to the next. All I can say is I trust my car and what it's telling me!!!!!!! I took this pic during that timeframe, instaneous MPG would not sit still long enough for you to get a pic like this while driving at same time. Nuff said.
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Old 05-27-2011, 05:03 PM
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Originally Posted by killerwatts View Post
I would love to take you up on your gas drinking offer with the chaser!!!!!!! It sounds like you are looking at the instaneous miles per gallon display (there are 2 MPG displays). If you are seeing 60-90 MPG than I would say wholeheartedly doubt what you are seeing if you are looking at the correct display. Based on the distance I traveled I have no doubt that my MPG display is pretty accurate. I did not say I got 31 mpg the entire trip just for a time frame (after fill up and for a good distance and yes it varied but I was able to get to 31 and it held at 70 MPH constant until conditions changed or I speed up again. I also stated it varies with conditions ranging from running AC to high speed, hills, stop and go,type of gas (I was using shell V-power case you are wondering) general maintenance etc. The display on my vehicle is pretty darn accurate and I have gotten well over 550 miles out of a tank of gas on highway driving while seriously fracturing the speed laws (got up to 120 while following a corvette)and even with the high speed chase which was still on my first tank leaving chicago and the varying speeds from corvette run to basically 70-75 miles MPH I did not do my first fill-up until about 45 miles from Maryland border on PA side at which my miles you can go on gas display showed me 5 miles left with current tank of gas (That's the point I found out how accurate the displays are). Based upon what I put in tank I don't doubt my car. Mine is doing what it's capable of doing or exceeding accordingly. In either case it is what it is and I was not looking at insant mpg which is all over the place from one second to the next. All I can say is I trust my car and what it's telling me!!!!!!! I took this pic during that timeframe, instaneous MPG would not sit still long enough for you to get a pic like this while driving at same time. Nuff said.
NO, NOT "nuff said"...you have proven nothing and not even indicated ANY fact or evidence.

AS I STATED, I am NOT talking about instantaneous readout or AVERAGE...I am talking about reality!

I am truly trying to give you the benefit of the doubt with regard to your understanding my point...AND the definition of true mpg.

First, 550 miles + on a tank is 24-25 mpg without totally draining it (do the math), exactly as expected. I REPEAT: 680 MILES + would be 31mpg!!!!!
I've gotten up to 25.4 while driving 80-105mph on a vacation, checked the correct way...but admittedly lost a little elevation on the drive and lost a little mpg on the way back, as expected.

Your readout does NOT measure gas passing into the engine...doesn't work that way...it is a general guess determined by vacuum, throttle position, current speed etc...AGAIN, it does NOT measure gas coming through the lines. If you trust it, you are deluding yourself.

A photo of average mpg readout means NOTHING...it can be reset at anytime while moving, doesn't indicate level driving...a parlor trick at best. I have logged an average reading of 90mpg (SERIOUSLY) by resetting at the top of the mountains before a 15 mile coasting descent, just as a joke for friends.

I'll repeat ONE MORE TIME: Level driving to and from a location, NO READOUT, just gas amount-distance-calculator tells the story.
INDEPENDENT confirmation of a 31 mpg claim is IMPOSSIBLE...will not happen....NOW: NUFF SAID!!! ....YOU LOSE. PHYSICS and THE TRUTH WIN!!! ....dream away, I DO NOT BELIEVE IT!!! I will not call you a liar, but I will call you MISTAKEN...you really DON'T seem to understand and there's apparently NOTHING I can do about that.

By the way, I have a car that runs on nothing but water, will go 300mph and I use it to get around on my 1/4 million acre unicorn ranch. This is true because I say it is. Do you doubt me?

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Old 05-27-2011, 08:29 PM
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My 2001 A8L is getting about 19.5 avg, HWY with no wind i can get about 28mpg!! going about 70mph..

City I say about 17, I drive mostly HWY to work and some city..but real happy, especially when compared to my Navigator!!! lol
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Old 05-27-2011, 09:19 PM
  #19  
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Originally Posted by silverd2 View Post
The only thing you can do to improve your mileage is get a smaller car...or coast everywhere you go

19.5mpg combined city/highway means everything is in good shape. 100% highway, you'll get about 24mpg max.
It's a 4156 lb car with a 310hp V8 and fat tires...physics is physics...forget about gas mileage, enjoy the ride and the power.

This is an infinitely better, safer and more sophisticated car than a Q45...a whole different animal...be happy for the improvement.
Is the A8 really 4156 lbs? I thought it was lighter than that with the aluminum chassis?
I agree...19.5 is pretty good. I was getting 16.5 combined highway/local, and some rush hour traffic. Then I got nabbed going 89 MPG...and have since slowed down. Now I get 18.5. Who would have thought? ;-)
I too have seen 24-25 mpg when driving long distances on the highway. I also have older S6 w/2.2 turbo, and the best it gets at 70 MPH on a trip is 21 mpg. If driving in and out of the city all week, with lots of lights and stop signs, both cars get about 11 mpg. As you mentioned...physics.
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Old 05-28-2011, 04:19 AM
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Originally Posted by SCL View Post
Is the A8 really 4156 lbs? I thought it was lighter than that with the aluminum chassis?
Although aluminum, more metal and thicker sections for exceptional strength...still lighter and stronger than equivalent sized MB & BMW of the same years.

Check out specs, including curb weights:
https://www.audiworld.com/model/a8/content.shtml
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