MK7 GTD - Real Life MPG

[fredgroves]

Woody, not being funny, but have you learnt to take your foot completely off of the gas when you don't need it? That's probably the biggest killer on fuel over motorway distance.

Or alternatively, do you put your ACC on when you are on the motorway? 20 miles at 65mph on ACC providing the temperature is above about 10 degrees C and assuming that its not a climb from the foothills of the Himalayas to Everest....

[djwoody]

My commute is 20 miles each way and I stick to 65mph.

I drove from Middlesbrough to Leeds last week and it only got up to 47mpg sticking to 70mph.

I have had the car for around 6 months and have just had the oil changed a month ago, fuel consumption is exactly the same.

I wonder if it could be something else, fuel filter perhaps?

20 miles each way on your commute - your DPF should be as clean as a whistle with normal driving enough to provide passive DPF regens. Your car definitely doesn't seem right. I drove my GTD a lot harder (higher average cruising speed than you seem to be doing and got far better mpg. Is it still under warranty (just)? Could be a fuel filter or stuck EGR valve.

Is your car manual or diesel? Manuals are around 10% more frugal like-for-like in my experience. Might be worth getting your brakes checked for excessive wear too.

I have a 20 mile commute and this week, i'm driving an Audi A3 150TDI Saloon courtesy car (and driving it very hard), still managing 60mpg to work and 55mpg home (roads a bit busier going home) - i'd expect a GTD to be 10% thirstier than this car.

Maybe try a fuel additive for cleaning the fuel system, like Wynns Xtreme diesel system clean?

My car is out of warranty now and is a DSG so I do expect slightly lower mpg than a manual.
When I first got the car I ran a tin of BG244 thru the system and on each fill up I use a shot of millers.

[djwoody]

Woody, not being funny, but have you learnt to take your foot completely off of the gas when you don't need it? That's probably the biggest killer on fuel over motorway distance.

Or alternatively, do you put your ACC on when you are on the motorway? 20 miles at 65mph on ACC providing the temperature is above about 10 degrees C and assuming that its not a climb from the foothills of the Himalayas to Everest....

Yes I do take my foot off and use the engine braking rather than using the brakes.
I normally use the ACC on 65 and have also tried the journey without ACC and both return around the same mpg.

I owned a 3.0TDI A4 before this and that was returning 42mpg on the commute (and that was driving anywhere between 65 and 80). I have been driving like a nun in the GTD and can only just about manage that.

[fredgroves]

Is that maybe 18 ish miles at 65mph with a couple each end of winding roads?

It really shouldn't be as low as you say. I'm sure if I knocked mine back to 65mph I'd get more... let me try tonight. My regular run is about 20 miles of mainly dual carriageway and motorway without jams.

Have you checked your tyre pressures btw? Make sure you haven't got them set for the wrong load.

Not got roofbars on? Windows or sunroof open?

[djwoody]

Is that maybe 18 ish miles at 65mph with a couple each end of winding roads?

It really shouldn't be as low as you say. I'm sure if I knocked mine back to 65mph I'd get more... let me try tonight. My regular run is about 20 miles of mainly dual carriageway and motorway without jams.

Have you checked your tyre pressures btw? Make sure you haven't got them set for the wrong load.

Not got roofbars on? Windows or sunroof open?

Yes it's around 16 miles at 65mph and 4 miles urban, no jams.
I'm running 19s and have 38psi in, no roofbars, windows open etc.
Very strange...

[fredgroves]

OK,  so I have a five door manual 14 plate gtd with 18's on it and no passengers or junk in the car.

Temp was 16 degrees Celsius. Car started after eight hours in work car park.

21 miles covered.  3 of normal roads than sixteen of dual carriage way and motorway with acc set to 66mph.  No traffic.  Then two miles of normal roads. 

56.4mpg.  That's a bit better than normal,  probably because I normally do 70mph on acc.

[monkeyhanger]

Ambient temp and humidity is a significant factor for TDIs.

Yesterday in the coutesy A3 150TDI I was getting 60mpg to work with an ambient temp of 17C. Today, the coldest morning in ages it was 9C and I got 52mpg driving it the same way. I wish Audi would get the wife's A1 fixed so that I can have my R back off the wife - she's started using Yankee Candle sticks in the air vents!

[djwoody]

OK,  so I have a five door manual 14 plate gtd with 18's on it and no passengers or junk in the car.

Temp was 16 degrees Celsius. Car started after eight hours in work car park.

21 miles covered.  3 of normal roads than sixteen of dual carriage way and motorway with acc set to 66mph.  No traffic.  Then two miles of normal roads. 

56.4mpg.  That's a bit better than normal,  probably because I normally do 70mph on acc.

Wow, that is good. It'd be pleased with that. Mine has 19s and a DSG so I'd expect slightly less. Would love to break the 50mpg mark on a 20 miles route.

[fredgroves]

OK so there is the answer,  I'd have guessed at 5mpg difference for both dsg and nineteens so that's about right.

[fredgroves]

I meant to say,  that's with the mode set to "normal".  I think on dsg if you use eco mode it does something about coasting and is earlier shifting? (makes little difference in manual)