Audi A3 poor efficiency?

oli356 · 21 Dec 2015 at 14:49

My car at the moment is a 64 plate Audi A3 Sportback, 2.0 TDI (150PS) with the S-Tronic gearbox.

I'm not sure if I'm just expecting too much out of the diesel or if I'm just driving poorly

My commute is less than 30 miles a day so I don't expect great mpg during that (a bad journey can be 30-40), but when on the motorway I'm a bit disappointed

I was driving back from London yesterday so an 80 mile drive, most of that being on the M25 and M4. I was on cruise control at around 82 mph for 90% of the motorway. At the end of the journey I had averaged 45 MPG. I previously had a 1.4 85PS Petrol, VW Polo so my only comparison is that - but I'm sure with that car for a journey like that I could get similar mpg. I think the A3s computer is saying that the average is also around 45 MPG for the 3000 miles I've driven it so far.

My friend has a 10 year old Diesel Mondeo and it surprises me what mpg he can get (better than me) considering the older, heavier car and he drives quicker than I do usually; so I'm feeling a bit like - uhm.....what's the deal here.

Does this sound right and I'm overthinking it, or is it a bit poor? I hear that auto gearboxes don't help efficiency but surely not by a great deal?

Oli

arctine · 21 Dec 2015 at 14:52

45mpg at 82 mph seems pretty good to me?

rpstewart · 21 Dec 2015 at 14:55

Same car here but 6 months older. 45mpg is pretty much what I'd get on that trip at that speed. It does seem to make a big difference going at 80+ rather than 70-75, if I'm lighter on the right foot I can see well over 50mpg.

Which driving mode are you using? I can get a fair bit more in Economy with no cruise than I can in normal with cruise.

oli356 · 21 Dec 2015 at 14:57

arctine said:
45mpg at 82 mph seems pretty good to me?

Maybe it is... not got enough years in a variety of cars hence the question really

.

Never driven a diesel either but always just hear that they are the best for motorway driving so possibly explains the higher expectation!

rpstewart said:
Same car here but 6 months older. 45mpg is pretty much what I'd get on that trip at that speed. It does seem to make a big difference going at 80+ rather than 70-75, if I'm lighter on the right foot I can see well over 50mpg.

Which driving mode are you using? I can get a fair bit more in Economy with no cruise than I can in normal with cruise.

I did think about going into the 70s but an empty M25 at 70 is horrible!

I've been in the efficiency drive mode since I bought it really, rarely go into auto.

arctine · 21 Dec 2015 at 14:58

My 2.0TDI A4 gets about 48-56mpg on motorway runs at 70mph.

eatcustard · 21 Dec 2015 at 15:00

arctine said:
45mpg at 82 mph seems pretty good to me?

This

rpstewart · 21 Dec 2015 at 15:03

oli356 said:
I've been in the efficiency drive mode since I bought it really, rarely go into auto.

Efficiency mode doesn't really work with cruise - it rarely properly lifts off and coasts so there's no real benefit. I also found that normal mode was better round town, the efficiency mode shifts up too early and too slowly so you end up booting it more to get anywhere.

Dogbreath · 21 Dec 2015 at 15:04

DSG gearboxes are often less efficient than a manual gearbox as well, so you'd need to compare like with like (assuming your friends Mondeo didn't have DSG...).

You also need to actualy measure your fuel consumption. Comparing the fuel computers estimated consumption between different cars is pointless, they are rarely very accurate.

[TW]Fox · 21 Dec 2015 at 15:13

Slow down a bit then you will get the 50mpg you want.

oli356 · 21 Dec 2015 at 15:26

rpstewart said:
Efficiency mode doesn't really work with cruise - it rarely properly lifts off and coasts so there's no real benefit. I also found that normal mode was better round town, the efficiency mode shifts up too early and too slowly so you end up booting it more to get anywhere.

Would it make more sense then to use auto with cruise?

Dogbreath said:
DSG gearboxes are often less efficient than a manual gearbox as well, so you'd need to compare like with like (assuming your friends Mondeo didn't have DSG...).

You also need to actualy measure your fuel consumption. Comparing the fuel computers estimated consumption between different cars is pointless, they are rarely very accurate.

Yeah his mondeo is a manual so not a like to like. I do log my fuel on fuelly.com actually, just checked it. So at the moment the A3 has average 42.5mpg, so a couple less than the computer - with the best tank being 47.9.

[TW]Fox;28965544 said:
Slow down a bit then you will get the 50mpg you want.

That would work.

acemastr · 21 Dec 2015 at 15:28

Cars aren't 'designed' for that speed and be efficient, drag, wind resistance and the rpm/turbo usage won't be in tune. Still, that mpg is pretty good for the speed!

cuke2u · 21 Dec 2015 at 15:32

Reset the mpg when you hit the motorway and see what your average is then, you are getting a distorted figure by combining different driving conditions. I get 55 mpg from my 1.4 a3 saloon...

oli356 · 21 Dec 2015 at 15:45

chriscatt said:
Reset the mpg when you hit the motorway and see what your average is then, you are getting a distorted figure by combining different driving conditions. I get 55 mpg from my 1.4 a3 saloon...

When I was watching it "live" it was often in the 30s and then going up to 60 - 100 if going down a slope.

Well, at least people think its ok so I can stop worrying now. I don't do tonnes of miles anyway (yet bought a diesel I know), so the £ in fuel isn't probably a huge amount away and I like the car overall

Ryan-3 · 21 Dec 2015 at 15:48

chriscatt said:
Reset the mpg when you hit the motorway and see what your average is then, you are getting a distorted figure by combining different driving conditions. I get 55 mpg from my 1.4 a3 saloon...

I did that and managed over 50mpg in my Cooper S, albeit over a reasonably short distance.

Darryl_1983 · 21 Dec 2015 at 15:53

I've got an older 2.0 TDI Jetta, that can see 60mpg on a sensible drive to work, as it's mostly 40-50 mph roads with little stopping and lots of average speed cameras. On a motorway at around 70mph, it'll give me around 50mpg. It starts dropping quite quickly over 70mph though.

As already mentioned what you're getting sound about right/good. Slow down to sub 70, and the mpg should increase nicely

jono_astra · 21 Dec 2015 at 16:06

Akagi · 21 Dec 2015 at 16:08

82 is too fast if your primary concern is fuel economy. If you drive at 60 I expect you will get over 60MPG easily.

I've seen 56MPG on a run in Dads 2001 A6 1.9TDI before when driving at 58~ in the inside lane of the motorway. With a full boot and 3 people besides myself in the car.

My own car is a totally different beast, but just as an example I average about 30MPG at 80, and 40MPG at 60.

The_Abyss · 21 Dec 2015 at 16:19

oli356 said:
I did think about going into the 70s but an empty M25 at 70 is horrible!

What is this empty M25 you speak of?!

Akagi · 21 Dec 2015 at 16:24

An empty M25 is better at 100MPH until you get pulled over and arrested.

(not talking from experience)

Scania · 21 Dec 2015 at 17:00

~45mpg for an 80mph journey average strikes me as pretty damn good tbh!

My other half has a 12plate Focus 1.6turbo diesel, it'll easily achieve 50+ mpg tootling about and on a motorway run it'll do a lot more so long as you stick to 65 - 70 mph, as soon as you try to maintain 80ish mph it's mpg drops considerably.

As already said, ease off a touch and reap the mpg reward, if you want to do 80+ then take it as a given your mpg will drop and by quite a margin.

My 15year old 530i petrol will get (more often than not) ~35mpg on a steady 70mph motorway run, if I up that speed to 80mph it's nearer 28mpg (the higher the speed the harder the engine works etc) which I fully accept, I suggest op you do also or,just wind it back a bit - simples.