A6 40 TDI fuel economy?

[A6 Avant]

Out of interest, roughly what mpg are you getting from your 40 TDI?

According to the car mine is averaging around 41mpg (mixed driving) so roughly 500 to 650 miles per tank depending on the type of driving.

Seems to be roughly 38mpg around town and 45mpg for longer journeys but the conditions affect this figure quite a lot (worse in cold/wet weather).

Pretty sure I remember getting 55mpg at one point on a long journey when I first got the car, but that was in very warm weather and on different tyres.

 

[relytyler]

48.5mpg on long term (3 yr) average. Typically, no lower than 45mpg on short journeys, which is 15-25 miles for me. Sometimes 52+ mpg on longer journeys which involve a good section of 60mph limited motorway. I've even seen 60mpg on a journey which had a high proportion of 60mph motorway. Yes, cold and wet weather does make a noticeable reduction.

Your numbers do appear to be low.

 

[A6 Avant]

48.5mpg on long term (3 yr) average. Typically, no lower than 45mpg on short journeys, which is 15-25 miles for me. Sometimes 52+ mpg on longer journeys which involve a good section of 60mph limited motorway. I've even seen 60mpg on a journey which had a high proportion of 60mph motorway. Yes, cold and wet weather does make a noticeable reduction.

Your numbers do appear to be low.

Thanks for your reply - that sounds like pretty decent economy.

Out of interest, which tyres do you have fitted? I have quite grippy performance tyres fitted which have definitely improved handling etc but I’m thinking they could also be reducing the mpg.

 

[relytyler]

P-Zeros (PZ4): https://www.blackcircles.com/catalogue/pirelli/p-zero/245/45/R19/Y/102/f?tyre=40973586

I wouldn't have thought tyres account for any more than a couple of mpg.

How, where, and journey distance will make a big difference of course. Balanced or mixed is how I would summarise my use of the car.

 

[elan2s]

On my old 40TDi Sport I got an average over 2 years I achieved an average of 47.18mpg over a distance of just under 18,000 miles. Over that time the worst brim to brim I got was 43 and the best 50.8. I recall on a trip back from Manchester at night I actually achieved over 60mpg, but that was exceptional. By comparison my current 40TFSi is delivering an average of around 32, but I am doing far fewer longer trips than I used to so that is having a negative impact on consumption. Tyres on the TDi were Bridgestone Turanza T005 and on the TFSi they are Pirelli P7 (both 225/55/18)

 

[spartacus68]

All things being equal. Diesels like decent ambient air temperatures, air-con off, tyres at correct inflation, no roof box or bike carrier, and run on premium diesel. If you're concerned, then run a can of Forte diesel conditioner through it once you're down 80 miles or so on the motorway and give it a blast. Replace fuel filter afterwards.

 

[A6 Avant]

Thanks for your replies. I'm perhaps doing slightly shorter day-to-day journeys than some of you at the moment which is probably a factor. The car definitely comes into its own on longer journeys though.

I also have the air con permanently on in 'eco mode' after needing to have it regassed as apparently the seals dry out if it's left off for long periods which allows the refrigerant to leak out. I'm not sure what impact this is having on economy but I might try turning it off for a few days and see if that makes any difference.

Another thing I've noticed is that even if I turn the air con off completely, under the 'energy consumers' tab it still says 'air conditioning' as something that's using additional energy. This only goes away if the climate control system is turned off completely - I'm guessing this is normal?

 

[elan2s]

I just leave the a/c on Auto the whole time and have always done so with all my cars. Only time I would turn it off is off I needed to drive with the windows open for some reason. The amount of energy it uses is tiny in the overall scheme of things.

I have found (on both diesel and petrol cars) that the first couple of miles of my journey can have a massive impact on fuel consumption. If the first couple of miles (while the engine is warming up) is slow speed and lots of slowing and accelerating then the overall consumption for the journey can be quite high. If it is reasonably fast steady speed driving then the consumption is much lower. As you say air temperature also has a big bearing, especially for diesels

 

[DaveW]

Have you tried Efficiency Mode in drive select?

 

[A6 Avant]

Have you tried Efficiency Mode in drive select?

Yes and it doesn't seem to make any difference other than perhaps on long journeys.

 

[A6 Avant]

I just leave the a/c on Auto the whole time and have always done so with all my cars. Only time I would turn it off is off I needed to drive with the windows open for some reason. The amount of energy it uses is tiny in the overall scheme of things.

I have found (on both diesel and petrol cars) that the first couple of miles of my journey can have a massive impact on fuel consumption. If the first couple of miles (while the engine is warming up) is slow speed and lots of slowing and accelerating then the overall consumption for the journey can be quite high. If it is reasonably fast steady speed driving then the consumption is much lower. As you say air temperature also has a big bearing, especially for diesels

I think you might be right about the first couple of miles of the journey having a significant impact on the overall MPG, especially if it's not a particularly long journey.

I'm going to try turning off the aux heater (which I think burns fuel at the start of a journey to heat up the cabin more quickly) now the weather is improving although I'm guessing it doesn't come on anyway when the ambient temperature is higher?

I'm going to try an additive/cleaner and change the fuel filter if anyone has any recommendations for a good one to use?

 

[elan2s]

The Aux heater should only come on when the ambient temperature is low (?below 5c). Likeyou Iused to think it was fuel driven, but I believe that only applies to the system they fit in cold countries (eg Scandinavia) where you can pre-heat the car before you get in. The standard Aux heater is actually electrical. Still uses fuel but not as much. Think Audi recommend the fuel filter on diesels is changed every couple of years

 

[A6 Avant]

The Aux heater should only come on when the ambient temperature is low (?below 5c). Likeyou Iused to think it was fuel driven, but I believe that only applies to the system they fit in cold countries (eg Scandinavia) where you can pre-heat the car before you get in. The standard Aux heater is actually electrical. Still uses fuel but not as much. Think Audi recommend the fuel filter on diesels is changed every couple of years

Interesting, thanks for explaining that. I’ve turned it off and it hasn’t made a difference as expected because I don’t think the car would be turning it on at current temperatures.

I always find it strange that the service plan doesn’t cover things like the fuel filter, air filter, brake fluid etc as these still need to be done as part of regular maintenance so they should be included.

 

[elan2s]

Interesting, thanks for explaining that. I’ve turned it off and it hasn’t made a difference as expected because I don’t think the car would be turning it on at current temperatures.

I always find it strange that the service plan doesn’t cover things like the fuel filter, air filter, brake fluid etc as these still need to be done as part of regular maintenance so they should be included.

I think it is because the Service Plan only really works with a car being on fixed servicing it only covers res those items that are scheduled within a 2 year timeframe, fuel filter and air filter have longer change intervals, whilst pollen filter is every 2 years and covered. However that argument fails when it comes to brake fluid as that is now back to being every 2 years (for a while Audi had the first brake fluid change after 3 years)