Poor fuel economy on diesel 170 4x4 Estate

[BD314]

I've been running my DSG Superb for about a month now (13 plate 12,000 miles), and I'm quite disappointed with the fuel economy I'm receiving.  My journey to work is 100 miles round trip, mainly with dual carriageway, and some urban/town driving.  I've got a fairly light right foot (well I think so), as there's little opportunity to do anything other than follow the car in front.

 

The display is reporting around 40mpg, but I'm only getting around 430 miles per tank (leaving 20 mile range margin).  If I measure more accurately from brim to bim fill, I'm getting more like 36mpg!  This tallys better with the mid 50's litres I put in each fill.  So it would seem that the onbaord computer is measuring about 10% optimistic.

 

Is this normalboth for the computed economy and poor performance, or could I have a problem ?  I had expected to get mid 40's mpg.

Edited 10 December, 2014 by BD314

[psycholist]

The fuel consumption calculation is usually optimistic, usually by up to 10%, mine was more like 7% last time I checked. I can get 50 mpg easily enough on a 2WD manual 170 diesel driving for an hour in traffic at around 50 mph with the odd bit of hard overtaking (I may be doubling that speed on occasion). 4WD does hit the fuel economy in terms of both drivetrain friction and extra weight and the DSG box is less economical than the 6 speed manual but your numbers do seem low. Does using fuel from a different petrol station make any difference? 

[BD314]

I generally fill with either Shell or BP and it doesn't seem to make much difference.  I've checked the tyre pressures and they're slightly higher if anything, so it's not that.

[Superb170]

The on-board computer will generally be around 10% optimistic as most of us can attest to.  That figure does seem low though regardless of the 10% margin.  Was it serviced before you bought it although you'd imagine filters etc shouldn't be too bad at that mileage?  Are you running normal tyres as that would impact fuel economy or do you carry any heavy loads?  The DSG and haldex 4x4 system does add weight and lowers fuel economy but again not to that extent.  Does the car run okay generally or do you feel it sluggish?

[Bristolf2b]

I have a manual 170CR 4x4 estate, the same age with 17000 miles. On a run like you describe it will do 43-45 corrected mpg ( maxi dot tells me 46-50) round town/cross country it does 38-42 corrected.

The extra weight and drag does hit economy without a doubt, but I am happy to accept that for the benefits the 4wd gives me

Edit: I think the 4x4's have lower gearing as well which affects motorway mpg

Edited 10 December, 2014 by Bristolf2b

[silver1011]

The things that count against increased fuel economy:

 

170bhp over 140bhp - check

4x4 over 2WD - check

DSG over manual - check

Estate over saloon - check

 

My daily commute sounds very similar to yours (mainly dual carriageway / motorway, 120 mile round trip).

 

I have a 140bhp 2WD manual saloon and am averaging 49MPG over the last 45,000 miles / 18 months, or in other words I see approx 500 miles per tank.

 

So for all the additional benefits or features listed above the trade-off is 70 miles per tank, which isn't too bad really.

[tmg]

hmmm

 

so I have the 170 combi 4x4 (2012) and chipped. 

 

most i ever get is 45-46 on a motorway trip at 120 km/h (80 mph in old money)

 

my old superb (1.9 tdi 130 bhp) always gave in the mid 50's

 

I was putting it down to:

4x4 - extra weight (around 300kg iirc)

combi - extra weight 

2.0 CR with DPF filter vs. 1.9 tdi without

panoramic roof - heavier again (iirc)

[LS108]

25.000 km on 4x4 DSG estate. 40 mpg.

Half mileage is city, half - highways (120-140 km/h).

[superbpete]

1. The cars not run in yet it will get better with more miles the engine still very tight.

[Too Tall]

You only have the car a month, correct?

 

it takes about 6 months before you *know* a car in my opinion. You get to know where the good gears are (plenty of pull and not alot of gas), how far from red lights you can start coasting in gear while using zero fuel. You get to know the "roll-off" point of the throttle, when you're cruising along and you can lift your foot ever so slightly for a big reduction in consumption but while keeping the speed the same.

 

Top tip?

 

Start tracking your consumption using Spritmonitor or Fuelly...you'll gain valuable insight into your consumption figures...you can add data points for AC or Winter Tires, and you can discover when or where you used more/less fuel.

 

Here's my graph from Spritmonitor (in L/100km, so higher = bad, lower = better)

 

 

This is over 3 years time in a 1.9PD Octavia II. Bought it in winter. You can tell in the beginning I started high (new car+wintertires), then progressively less and less fuelconsumption.

 

The 2 later higher bumps are also winters, where I used winter tires. But you can tell my 1st winter right at the start was very high, out of comparison with the other 2 winters.

 

The lower dip between the 2 winters was a summer when I had the car chipped. So you can tell the car was pretty economical in summertime to begin with, but after chipping it became even better. Small difference (you'll never get the cost of the chipping out of it) but still.

[Too Tall]

And here's my 140 CR Superb. Only datapoints for a year, so that explains the irregular graph and bigger 'spikes'

 

 

You can see on the very left I bought it (again) in wintertime. VERY high consumption. Now on the very right you can see the lowest fuelling, then winter starts, then I put winter tires on (and the last 3 dots jump because of this).

 

More difficult to see, but again you see I "learn" to drive the car economically over a year's time. If you would draw a line through the graph with the average, you'd get a slowly declining line. So better fuel consumption.

 

Give it time!

[BD314]

The on-board computer will generally be around 10% optimistic as most of us can attest to.  That figure does seem low though regardless of the 10% margin.  Was it serviced before you bought it although you'd imagine filters etc shouldn't be too bad at that mileage?  Are you running normal tyres as that would impact fuel economy or do you carry any heavy loads?  The DSG and haldex 4x4 system does add weight and lowers fuel economy but again not to that extent.  Does the car run okay generally or do you feel it sluggish?

 

And here's my 140 CR Superb. Only datapoints for a year, so that explains the irregular graph and bigger 'spikes'

 

 

You can see on the very left I bought it (again) in wintertime. VERY high consumption. Now on the very right you can see the lowest fuelling, then winter starts, then I put winter tires on (and the last 3 dots jump because of this).

 

More difficult to see, but again you see I "learn" to drive the car economically over a year's time. If you would draw a line through the graph with the average, you'd get a slowly declining line. So better fuel consumption.

 

Give it time!

 

Thanks all, the graphs are really interesting.  The car performs well in all other respects, so perhaps I just need to be more patient.  As you say, I've only had it a month so we perhaps need to used to each other!

 

I had no-idea that the Haldex added so much weight, which probably isn't helping, but I still think the benefits are justifiable (just!).  I'll keep a close eye on tracking my consumption.  I guess I was a little disappointed that the Maxi dot only made matters even worse when corrected. 

 

I hadn't really thought about winter driving, but although the tyres are standard (what was fitted on delivery), I guess there's greater load on everything with lights, heaters etc.  Hopefully the engine will loosen up a little as well once I've got some more miles on it.

 

Any more thoughts still very welcome though!

[DenzilDexter]

Haldex appears to only be 77Kg if you compare kerb weights on the brochure.

2.0 TDI CR 170PS 4x4 Combi 1,579kg

2.0 TDI CR 170PS Combi 1,1502kg

Difference of 77kg

[BD314]

77kg sounds better. 300kg would a very high proportion of the cars weight, although many do quote this figure. I don't have a spare wheel so not sure if that's applicable to just 4x4s, to compensate, but that would only be about 20kg.

Has anyone any experience of tyre pressure affecting mpg? In my last car (Vauxhall), just a couple of psi made quite a difference.

[Bristolf2b]

.

Has anyone any experience of tyre pressure affecting mpg? In my last car (Vauxhall), just a couple of psi made quite a difference.

Pressures seem to make less difference with the Superb than my previous car, an Audi A4 Avant. With that, adding 5psi gave measurably better fuel consumption (+8-10%) on a long run. However, I have not persisted in adding pressure to the Superb, as the ride is more adversely affected Edited 11 December, 2014 by Bristolf2b

[Too Tall]

77kg sounds better. 300kg would a very high proportion of the cars weight, although many do quote this figure. I don't have a spare wheel so not sure if that's applicable to just 4x4s, to compensate, but that would only be about 20kg.

Has anyone any experience of tyre pressure affecting mpg? In my last car (Vauxhall), just a couple of psi made quite a difference.

 

Upping the pressures a little bit (and checking them every month), removing that boat anchor that you always keep in the boot but never use are little things you can do to improve MPG.

 

The biggest modification to improve MPG, it's all about you...

 

1. Coast to red lights as far as possible

2. Slow down to go uphill

3. Speed up to go downhill

4. If you have to make 5 stops in town, make the farthest stop your first. A cold engine uses more fuel, so your car will be warmer when you travel the farthest first

5. Always park with your nose ready to go (if you don't need to access the boot) so when it's cold and you start the car, you can drive off instead of wasting fuel reversing

6. Drive less. Go on foot. Ride a bike into town. PLAN your weekends, if you have to visit family and there's a store on the way, go shopping then instead of going tomorrow.

7. Dont. Brake. Ever. Braking turns precious energy into useless heat. Anticipate. Anticipate. Anticipate.

8. Don't try to heat up the car while idling in the driveway. Get in, start the car, give it 10 seconds to circulate oil everywhere, then GENTLY drive off.

 

Mind you, SAFETY and NOT ANNOYING FELLOW MOTORISTS should ALWAYS trump fuel consumption. Don't be "that guy" with a powerfull car passing a lorry with a very tiny speed difference holding everyone up, because of your consumption.

 

It's a hell of a car, the 170 coupled with the 4x4. Enjoy it a bit. Consumption will get better!

Edited 11 December, 2014 by Too Tall

[BD314]

Thanks for the tips Too Tall. Its a great car, as you say, I'll be more patient and enjoy it.

[Brockysuperb]

The Belgian's tips esp 4 and 5 are really interesting. Thanks.

[LS108]

From other hand I would like to say some good words about Superb. I am using all 170HP it has, also driving rather fast in motorways (half of my mileage) - 130 km/h winter time (when good conditions of course), 160 km/h summer time. Also I am using autonomous heater every morning from November for 15-20 min (uses fuel as well). Still I get 7.1L/100km which is good figure having in mind the above mentioned conditions. After all it is big car with 4x4. Also this particular engine is not the newest in the VAG range. I thing Superb III with 190 HP engine will be more economical. 

Edited 15 December, 2014 by LS108

[2SkodaFamily]

I did a run to Donington and back yesterday. A roads down to Howden, then motorway (M62, M18, M1) to Donington.

 

Indicated MPG was 55, no doubt assisted by about 40 miles of 50mpg speed limit on the M1.

 

My mileage is nearly 64k now. Other than that, I have a 170bhp 4x4 estate. Mine has a manual gearbox though.