Hello all!

So to summarize (rather than create a long-winded post), I filled my fuel tank with premium fuel (obviously), put the car into Eco mode (occasionally Touring), drove with the sole purpose of dropping into V4 mode, and tried to cruise as much as I could, intentionally avoided speeds in excess of 55/60MPH, used cruise control, no use of the A/C nor ventilated seats, put practically zero stress on the engine, and came to smooth starts and stops.

That said, my total distance before having to refuel was approximately 270 total miles. Had I had driven like a normal human being in one of these cars, I probably would have barely achieved 200 miles.

I've done some research on the web and noticed that there are several factors for fuel economy issues, but rather than name them, I'd rather see if you all have any thoughts as to what it could be, or, instead, given my driving description, that this is actually normal and my fuel gauge just loves to drop with every drive I take, literally .

ABOUT THE CAR:
2015 A8 Z51
13,750 miles
All Stock OEM products (no enhancements of any kind)

Thanks in advance!

 

I am not sure that I understand your question right, but you think your car consumes too much ? If yes, how ,much did you have to refuel after 270 miles?
Just as an example of what the car is capable of: The best I ever reached under perfect conditions driving constantly 75-80 mph for about 80 miles with hardly ever breaking was 34 mpg.

Regards

Götz

 

Your car has a display that shows fuel economy. Take a picture and post it. Your post doesn't include enough information to make a meaningful pencil and paper calculation.

 

I run around 31-32 MPG on the highway and 17 in the city. With a 18.5 fuel tank, that'll get me over 500 miles before I panic and try to get it filled up.

Elmer

 

I would have to know how much fuel you used to even know what your fuel economy was. Did you put 10 gallons in at your next fillup? 15? Were they all highway miles, or some city? How high or low were your rpms averaging during that time? Impossible to say without any of the actual data (don't intend for that to sound snarky, just not a whole lot to go off of). I can say, however, that I can easily get 32 mpg out of mine if I baby it on my long drives to and from work (even after bolt-on mods). City driving and having some fun with it will, of course, greatly decrease that though

 

With the Z51 gearing 270 miles per a tank is about right with easy driving.

 

In normal mixed driving (50/50 city highway) I get about 300 miles out of a tank full... that averages out to about 19 MPG. I can get over 30 MPG cruising on the highway. On the flip side it gets about 6 MPG on track days Now stop and go city driving with lots of idling will kill your mileage since when the car is stopped you are getting 0 MPG. As mentioned by others the car will display your MPG both as you drive and as an average over various distances. The C7 is rated by the EPA to do 15 city and 25 highway MPG for reference.

Overall I think 270 per tank seems reasonable as the low fuel light comes on with about 40 miles to empty. If you put 17 gallons in that would yield 15.8 MPG.

 

My apologies, everyone!

I see your responses and I'll provide more information tomorrow. I just refilled my tank today (all 18 gals) and reset my instant economy readings. I'll provide more info! Thanks again!

 

An "Advanced Search" across the C7 sections here will give you more than any sports car owner should want or need to know about fuel economy topics, one and all. Most who have done tests report what some might consider little savings,, btw.

 

You might want to check your tire pressure.

 

***The testing is underway!***

Thank you all and I'll provide new feedback. I am almost at half a tank as we speak. I am almost expecting to spend $50 a week to fill the tank at the rate of which I drive, but it looks like I'll be able to go longer at this rate. To be continued!

Tire Pressure is 35 all around.

 

If it makes you feel any better, I put about 50 bucks in mine every two days. Long work commute, and I typically daily drive mine

 

Drove to Savannah (154 miles), around in old Savannah, then to Tybee Island, and then to my hotel, and then home another 154 miles and I had 1/4 tank left in the car.

I set the cruise control on 80 for the entire highway drive. These cars are awesome cruisers!

Elmer

 

I know most of the Corvette guys I know are like myself.. mileage is not even in our thoughts on a sports car. I guess if I just filled up and went like 1 mile and empty I would be concerned, but regular driving could care less.. it's a Summer Toy

 

I have found that my car uses much less fuel when in storage.....

Seriously, I have 2 C7's. A 15'Z51 Auto and a 16' non-Z51 Auto. Mileage doesn't seem to be much different. Most driving is either hwy or 45+ in town mph. Recent tune in 16' seems to have affected hwy mileage by a couple mpg. Doing an e-85 conversion and tune on 15' in Iowa this summer. Will be interesting to see the mpg difference. E-85 readily available and cheap there.

 

You're mileage will be HORRIBLE on e85.

I've got a '16 Z06 making 700hp at the tire on e85. I can get about 125 miles out of a tank of full e85 under normal driving conditions about 20 miles each way to work and back with mostly highway speeds of 60-85. Took it on a 1400 mile trip to Texas, Oklahoma, and back to Alabama and ran it on 93 the entire time and averaged 24mpg cruising between 80-90mph most of the way.

 

I can't bring advise to the thread. I've only had the 17Z for about 3 months and never looked at MPG. When I bought it I was told by the wife if she ever heard me B!tch about my MPG that it would be the day I would have to sell it.

 

Guys, you don't know how lucky you are in the US, I currently pay just over 7 $ per gallon....

 

That even seems terrible for E85. I'm around 660 at the wheels and can get 300 miles on a tank of E65 driving 65-80 on the highway.

 

OP;

Some common causes for poor gas mileage:

1. Incorrect tire pressure.
2. Bad/failing oxygen sensors.
3. Dirty air filter.
4. Clogged fuel injectors.
5. Wasting gas by idling.
6. Type of motor oil, synthetic VS dinosaur (conventional) oil.
7. Wheel alignment.
8. Elevation (topography) and/or headwind.



Many thanks,

Ray