Fuel Consumption Improvements:

[bw10030]

I have owned my Superb Estate for 21 months now - and for the use I put it to, I absolutely love it! It's a 170 Elegance with the DSG gearbox, and one or two 'goodies' like the panoramic sunroof and park assist. In the 21 months of ownership, I have clocked up 40,000 miles, as I work away during the week. My 'typical' week consists of a 200 mile motorway trip at and indicated 74 mph, usually where conditions permit on cruise, with the A/C in 'Auto'. The motorways are the M6 (Preston to M1) and M1 south, so can be very busy - average speed is usually only 55mph for 170 miles on the motorway! During the week I do a 15 mile 'commute' on 'A' roads, so average about 500 miles per week.

 

I have noticed that the fuel consumption is steadily improving! This is good news, given the mileage I do! I always fill the tank to the brim (to ensure I have the range for each week), so each week my consumption figures are accurate. I don't trust the fuel computer to give me actual MPG, which is always too optimistic (see below).

 

I started off with 45 MPG, and have noticed steady improvement. I'm currently up to 52 MPG over the last month. I have noticed a drop over the winter months as well, which I put down to 'winter mix' diesel being sold to prevent freezing in cold weather?). The fuel computer shows 53 MPG to 61 MPG for these returns, by the way.

 

My question is - how much better will the consumption get? I'm assuming the consumption is getting better because the engine and other rotating 'bits' are easier to turn now they have some miles under their 'belts' - but what is a typical profile? Does the consumption level off once the running gear is completely 'bedded in' and then stay the same for years until something 'gives', or does it just steadily get better and better - and if so why?

 

Have any other high mileage, consistent journey driver seen the same? What does 'good' consumption for this car look like?

[wokwon]

In my last TDI it  leveled off after 60,000km.  That was the BKD engine (PD engine).

 

Only have 30,000km on the Superb so far (CFFB - common rail engine) and it still getting better so I guess it will be similar.

 

At 40,000 miles I guess you're about as good as it will get, unless you change your driving style or conditions.

Edited 24 July, 2014 by wokwon

[ILOVEMYSUPERB]

I found a brilliantly simple way to increase the mpg by 15-20%..... take the keys off the Mrs - heavy right foot doesn't come close.

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[Danny 57]

My 140bhp has just turned 30k miles and is still improving. Brim to brim 57 mpg which includes motorway Cardiff city centre and local town and village stop starts.

[Superb170]

My last Superb was slowly improving until around 70,000kms or so. On fact the whole engine only really loosened up properly around then!

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[cnc]

I always find all my VW group diesels give better consumption in the warmer months and worse when it gets colder.

[Supurbia]

Don't wanna put a pin in you but it is as said above the weather playing it's part,

 

fwiw your figures seem about right given the use, 61 is about as good as it's going to get tbh,

 

Also another consideration is if you do 200 and the last 40 of them you hit ideal traffic conditions and got the 60mpg showing but the other 140 miles were a bit of a slog by the time you filled up you'd probably find the reality is closer to 50 than 60 overall.

Edited 26 July, 2014 by Supurbia

[bw10030]

Thanks all, I'll look forward to some more improvements! To add spice to the discussion, my wife's Yeti (140 TDI DSG 4x4) started off at about 35MPG, and has been steadily getting better - last week on holiday in Scotland )1000 mioles covered), it returned 41MPG. So it seems all these angine types do it? Do manufacturers therefore use 'loose' (i.e. well used!) engines to get their MPG figures? If not they are missing a trick! 

[Tall]

You can get better economy if you strive for it - using cruise isn't the best. Say for the point of my illustration that you want to sit at 60mph, and say the average MPG while sitting at 60mph is 45mpg.

Watch a trip computer with instant mpg if you have one. Holding 60 mph uphills will reduce the mpg to maybe 25, but lifting off the throttle a little might give 32mpg, while only slowing the car to 54mph. Similarly allowing the car to speed up to maybe 70mph down hills using a light throttle might reduce the mpg from 99.9 to 70 or something, but the additional momentum gained means less miles to travel at 45mpg.

It can get a bit anal, but I've had a car go from average 38mpg to over 54mpg, with no difference in journey time.

Apologies if that comes across a bit granny-sucking-eggs-ish, it's not meant to be, it's meant to be helpful. It's what hgv drivers are taught for optimum fuel economy.

[Stinker]

You can get better economy if you strive for it - using cruise isn't the best. Say for the point of my illustration that you want to sit at 60mph, and say the average MPG while sitting at 60mph is 45mpg.

Watch a trip computer with instant mpg if you have one. Holding 60 mph uphills will reduce the mpg to maybe 25, but lifting off the throttle a little might give 32mpg, while only slowing the car to 54mph. Similarly allowing the car to speed up to maybe 70mph down hills using a light throttle might reduce the mpg from 99.9 to 70 or something, but the additional momentum gained means less miles to travel at 45mpg.

It can get a bit anal, but I've had a car go from average 38mpg to over 54mpg, with no difference in journey time.

Apologies if that comes across a bit granny-sucking-eggs-ish, it's not meant to be, it's meant to be helpful. It's what hgv drivers are taught for optimum fuel economy.

Agreed. I find maintaining a constant throttle position (within reason) will give far superior economy than constant speed (cruise control). On the flat get up to a reasonable speed say 60 mph and have look at the instantaneous mpg on the computer. Pick a figure, say 65 mpg (we're allowing for the 10% optimism of the computer, so really about 58 mpg) and gently let off the throttle till it's reading the 65 mpg we're looking for. Now memorise this foot pressure/throttle position and do your best to maintain it up hill and down (obviously lift off if you're going too fast). Try this for a while and see if the mpg improves. The further you can lift off and still maintain speed the easier on the fuel. Same with accelerating, gentler the better again within reason. Don't forget to treat yourself (and the car) to a really good blast in 3rd and 4th now and again. This will clean the pipes and the car will feel massively powerful after all the dawdling around!

As per Tall above, anal yes and apologies for condescension.