A6 2.0TDi Avant - Fuel Economy

[joshA6]

first post so please go easy.

I recently purchased a 2008 A6 TDi Avant (80k) with the 2.0 BRE 140hp engine. As far as I know it does not have a DPF.

Haivng run it for a couple of tanks, I was a little dissapointed with the economoy. I am currently averaging 39mpg on the DIS, and can manage 50mpg on the motorway (short run from cold, approx 20 miles).

Manual calculation tells me I am averaging all in 38MPG.

Would you say that this is normail for this car? Not fussed about inaccuracies between DIS and actual!

[nunncm]

Seems about right. I get a bit less than that when I pootle to and from work which is 10 miles each way semi rural. A6 is a big heavy car and the engine is reasonably powerful so it's not to be as frugal as a diesel fiesta. The best I've had is when I drove across the country, pootled around for a couple of days and then drove back (472 miles) and got 43mpg. my worst local is 36.5. This is worked about properly via fuel used rather than the DIS.

Anyway much better than my last A4 TFSI which only managed 26!

[NikB]

I have a 2.0 Tdi 170 and have a 4k mile average of 44.8 I can on a 50 mile run to work comfotably achieve 48mpg and if I drive witha pupose then between 40 and 42 depending on how spirited.

Car dosent average well with short Round town trips though 38 mpg ish.

[joshA6]

Do you think chipping it to around 175bhp will improve the economy. I suspect that the car is underpowered, hence the need to work the engine harder??

[nunncm]

Apparently it does and I am tempted but what are the long term affects? - these engines are tuned to this level for a reason by highly paid Audi designers, although I heard this is so that they run with rubbish fuel that you get in lesser developed countries, but saying that they do do a 170bhp one so would be interesting to know what other bits have changed, if any, to cope with the additional power? And what does this do to your insurance and resale values?

[imastu pidgit]

Interesting - almost in the same position, having just bought the same car, engine type and age, but with 88k on it. Only been two weeks so far, and I have a 12 mile drive to work, ranging from 40-45 mpg on the way in, (early) but only 32-38 on the way home (more traffic). First post etc etc.

I think it would be a lot better once it has warmed up - the engine temp is only getting to the middle of the guage once I get close to the destination each time - have still to go on a proper motorway run.

Agree with the earlier comment - it's a big car for a 2.0 litre to propel, especially when it's cold. It makes quite a change in every way from my previous BMW 540 touring (circa 7 miles to the gallon for the first mile or so on a cold day...)

Also thinking about the tuning angle - does anyone know if there any effect/reason not to do it on a car with mileage like mine (88k?)

[sja]

I'm pretty dissapointed with my fuel economy on a 2.0 140 tdi.
Its a 05 plater with 80k. I had it remapped from 1st day of ownership so cant comment on economy pre mapping.

I have pretty much similiar journey to other posts. 12 miles to work. I see 44mpg on journey to work and 38 on way home.
Using MMI I should be getting 40 mpg. But in reality its 33mpg. 21 litres = 150 miles. Approx 33mpg.
The MMI is pretty inacurate.

But as previosuly said the temp gauge isnt at the middle til I'm nearly at work so that cant help..

I havent really been on a good long motorway journey but I loaned car to a mate who took it to Blackpool
and he was impressed with the economy (havent got specific figures). But I suspect its those type of journeys
that it shines.

I sold my X5 as was sick of the economy, to be hosenst it wasnt musch worse than this in traffic.

[joshA6]

Having had my golf diesel chipped, I would say chipping by a reputable company is very safe. The fuel economy went from 55mpg to 60 ish on the same run as I take the A6

I am assuming that the 170 probably has a different turbo and a different ECU (one is siemens, the other is bosch but not sure which variant 140/170 has which one). I doubt the injectors are a weak leak even if they are different.

Assuming you do not have a DPF, you should see around 180 on a standard turbo. Remember that a good remap does not increase overall boost pressure too much. It's all the other maps that make the difference.

I am going to do a basic check on everything over the next month or so to make sure there are no problems before the remap.

The onlyu issue the car has is an intermittent shudder around 1800-2200 which I think is either a boost leak or a faulty coolant sensor.

[NikB]

in my experience re-map improves fuel economy slightly, my old A4 130 was remaped to 180 BHP with excellent results and a 5mpg average increase in MPG.
The 170 BHP engine is a common rail engine where as the 140 BHP slightly earlier engines are PD engines so quite a bit diferent in my understanding, I'm sure someone with better knowledge will either clarify this or correct me if I'm wrong, the 170BHP CR engine will remap to 208BHP and still return slightly better economy from standard.

[Seeker_UK]

Basically sounds about right to me. Quoted MPG figures are BS - they are derived from the car being driven on a rolling road in perfect conditions with the engine at the correct temperature etc etc.

For example, my 2.7 TDi should average 41 with 51 on a run. What I actually get is 34 average with 47-8 on a run. My "average journey" is a ten mile trip with dual carriageway for 5 miles and 30 mph zones for the rest.

My other half runs a 2001 A6 2.4 multitronic and she gets 33 mpg average! But then, she drives 40 miles a day almost exclusively on dual carriageways.

That was over the summer and now it's getting cold, I will see that drop by one or two mpg.

My rough rule of thumb when looking to buy a new car is to look at the urban consumption, use that as a basis for cost of ownership calculation and naything else is a bonus.