I've never had an S5, only A5's (because I'm even more of a boring and stingy old fuck than you!), previously 3.0TDI's and currently 2.0TFSI. I have always noted (for my current car) that a brimmed tank will render 455 miles on the DIS (rarely do I get anywhere near of course!). Apart from one time after a 900 mile holiday trip where I got a DIS average of 42mpg... the fill up after that rendered a 480 mile range on DIS. Several fill up's later on my usual cycle this was back down to 455 miles. I concluded that it makes an optimistic calculation based partly on recent mpg and perhaps other factors such as driving style. One thing I can say is that I have never observed an increase in range during any one tank cycle... never, not on any of the four A5's I've had.

 

i think more than anything it takes into account how economical you drive, my usual fill up sees me getting around 180-190m for around £30 of tescos premium fuel on the dash, however i very rarely get even close to 120m from it, as my daily commute is around 3miles, but computer usually takes around 10miles from the range each day, as they say you bought it for smiles rather than miles!

 

The miles to empty uses the overall average you have been getting to calculate miles to empty. If you have been driving hard/worse mileage the miles to empty will decline. I have seen as much as an estimated 385. Right not my MPG has been dropping severely (TBD cause) and the miles to empty is around 350 now.

NOTE THE MILES TO EMPTY IS VERY INACCURATE! You will not get as many miles as indicated. I started to monitor mine:

• After a fill up, I can drive for 40 miles or so before the miles to empty starts to go down.
• I have compared the miles to empty vs the odometer. For about the firs half tank, it is fairly close but after that the miles to empty will go down faster compared to the actual miles traveled

 

Miles to empty will constantly change depending on your driving. When you fill up it will update the range based on your previous drive to the station.

I get 120-130 miles to £40 of V power.

Might try Efficiency mode and see if actually makes a difference

 

Depending on how/where I'm driving I've had up to 425mte, but it never works out to that.
The majority of my driving is to/from work and I get about 20mpg (American gallon), and I see about 370.
On the interstate etc., I can get up to about 32mpg, where I see the 425.

 

When I first got my v8 S5 miles to empty when filled to brim was 290, now showing 320. Last owner rarely saw over 30mph on her commute, so I'd say it constantly changes.

 

I take the number it puts out there with a grain of salt

 

The closer you get to empty, the more accurate it becomes!

 

This is one question where I wish an Audi engineer would chime in.

 

Big tank of fuel sloshing about, hard to get a reliable reading. Plus at the start of the journey your MPG will be unsteady, so it's probably just a case of the maths going a bit wonky with all the constantly changing numbers.

 

Aaaaaand the car gets lighter so does more mpg! ha ha

Half a tank will weigh around 35kgs!

 

that is very true as you will ha e more weight in the car with the full tank, obviously whether it will make any significant difference is a question, but i never fill mine full, unless going for a long commute. At the end of the day dont think any of us bought these cars for the great mileage, otherwise you would be driving nissan leaf xD

 

Lots of interesting replies, thanks all!
After 2 weeks of commuting 30 miles a day in efficiency mode, filled up today and miles to zero is now up to 365!
Efficiency mode definitely makes a difference. It's very dull, but my commute offers no opportunity to boot it anyway, so might as well use it.
But as many of you have said, if you're worried about fuel consumption, you don't buy a supercharged V6.

 

Good thread indeed, basically I think that the calculation is made from the very recent driving pattern, so for instance when you drive up hill the car assumes that you have another 400km of hills to climb and the figure goes way down, then as you start to go down hill again the figure shoots up!!!!!! Madness, pinch of salt, I fill mine and zero the trip and I know more or less the average consumption and therefore range and of course that all depends on how heavy yer right foot is today.