I realise the whole "fuel economy" thing has been done to death, but after spending over £150 on fuel yesterday I thought I'd take a closer look at mine.

I've been tracking my fuel usage on http://www.fuelly.com/ for the last few cars and thought I'd see which car came closest to the manufacturers figures.

I've taken my Fuelly "average" as indicative of the manufacturers "combined" figure, my Fuelly "worst" as the manufacturers "Urban (cold)" and my Fuelly "best" as the manufactuerers "extra urban".

First of all my current car(s)

2012 Skoda Roomster 1.6 CR TDi - CO2 g/Km 124, VED £95 / Year

Claimed Actual Difference

Urban (cold) 49.6 38.4 -23%

Extra Urban 68.9 47.4 -31%

Combined 60.1 44.2 -27%

2002 Skoda Octavia 1.8T Elegance 4x4 Estate - CO2 g/Km 214, VED £260 / Year

Claimed Actual Difference

Urban (cold) 23.3 24.3 +4%

Extra Urban 39.8 31.6 -21%

Combined 31.7 27.8 -12%

Previous car(s) tracked with Fuelly.

2011 Skoda Octavia 1.8 TSi 4x4 - CO2 g/Km 180, VED £210 / Year

Claimed Actual Difference

Urban (cold) 27.4 27.0 -2%

Extra Urban 45.6 37.0 -19%

Combined 36.7 31.1 -15%

2007 Honda CRV 2.0 ES Auto - CO2 g/Km 195, VED £245 / Year

Claimed Actual Difference

Urban (cold) 25.9 18.4 -29%

Extra Urban 42.2 31.1 -25%

Combined 34.4 24.4 -29%

I realise the manufacturers figures are rarely achieved day to day, but was suprised by the margin between the claimed figures and my actual fuel returns.

Of note both my previous MkII Octavia 4x4 and my current MkI Octavia 4x4 virtually match their claimed urban figures and only fall short of their combined figures by 15% and 12% respectively.

I recently spoke to my supplying dealer regarding the Roomster's economy and they told me that "in the absence of any warning lights on the dashboard it did not warrant further investigation, until the car had covered at least 5K miles". The service advisor did however allude to several other customers who had complained of poor economy from 1.6 CR engined cars. He did say most of these had shown improvement with increasing mileage. By this logic I may have been better served buying a second hand Roomster (with 10K miles on the clock), rather than a new one!

The only other diesel Skoda I have owned was a 2007 1.9 TDi Roomster, which if memory serves me correctly, averaged around the 50 mpg mark.

Not sure what happened with the formatting??

I've attached the source data (.txt) for info.

fuel.txt

the roomster figures are bad, was worse than my 140mph vRS!.... I get the manufacturers figures (and do better ) with the mark II vRS easy...

easy 45 mpg, when drivivng "normally" when trying hard going to work to save money I can always run it above 50 mpg..... (and 30 mpg when hooning around! lol)

BUT your dealer is right, the engine needs to loosen up.... I couldn't better 35 mpg with less than 5k on the vRS... no matter what I did 35 mpg would be the best..

the figures above are done with 25,500 miles on

I take your point regarding the engine "loosening up", although if this was the case I would have expected to see a gradual improvement in my average economy over the preceding 2.5K miles. In fact my "best ever" was the first tank and the lowest figure was the time before last!

After 8 years and 110k I got the most out of my mk1 vrs for my normal weekly usage. 480miles on the trip (no expansion tank used) and showing 50mpg. Usually get around 420 in the past.

I have been playing with the mapping so not sure if that's effected it.

the roomster figures are bad, was worse than my 140mph vRS!.... I get the manufacturers figures (and do better ) with the mark II vRS easy...

I managed 20 mpg on an extended test drive in a Fabia vRS, this was somewhat better than the 12 mpg I managed in a Superb 3.6 though

I managed 20 mpg on an extended test drive in a Fabia vRS, this was somewhat better than the 12 mpg I managed in a Superb 3.6 though

lol... that just means you were drivivng them properly

Well my crtdi furby( the one I've just sold ) I was getting 62 mpg and 550 miles per tank 45 litres

I think it depends a lot on where you live ie what the traffic is like ie heavy or next to non existent. As one of Clarkson's pearls if wisdom say if you touch the brakes you should count yourself a failure, hen went on to say he had never touched the brakes on the motorway.

Whilst the above is nigh on impossible and you alway get some Tw^t pull out out you and slow your progress, contrary to the Highway Code, this I find is the major reason for being some distance from the manufacturers figures. If you do not use the brakes ie start slowing down by coming off the throttle at the point where momentum will take you up to the next junction or lights with only a dab on the brakes in the last second before the junction the fuel consumption, I find, gets close to the manufacturers figures. Small diesel engine in a big car seem to suffer worse as they have to use a higher percentage of throttle to get back up to normal speed.

Always use to be true with Carburettored engines, and I suspect is also true for indirect and direct fuel injected cars, that the further the throttle is pushed down the "richer" the air/fuel mix is and therefore the more inefficient the engine is. In Japanese hyper miling techniques they drive with just their big toe on the throttle and try to only depress the throttle a millimeter or two and achieve one or even 200 mpg in the Insight, Prius etc. There are some brilliant engines out there, the twin charge 1.4 TSI, the VVT 1.8 TSI and now the cylinder shut of Audi, Bentley etc TSIs which will filter down to Skoda in a few years time. A long with start-stop, aluminium bodies we should be getting 80-100 mpg cars in 5 to 10 years but they will proably cost more which partly offsets the savings.

Diesels, unless there is a new breakthrough ie 2 stroke, w"nkel or something like that its days are numbered, too expensive, too heavy and takes up too much engine bay space and direct injection turbo petrol are closing the efficiency gap. The new Peugeot diesel-hybrid is getting bad reviews as expensive and not that good.

Edited 11 March, 201214 yr by lol

Diesels, unless there is a new breakthrough ie 2 stroke, w"nkel or something like that its days are numbered, too expensive, too heavy and takes up too much engine bay space and direct injection turbo petrol are closing the efficiency gap. The new Peugeot diesel-hybrid is getting bad reviews as expensive and not that good.

Diesels are not going to go away any time soon - there is a lot of rubbish talked about the ten's of thousand of extra miles you need to do to pay back the extra cost - the text below is cut from a previous thread - the mpg figures are all 100% calculated rates. The actual price for the fuel doesn't really matter for this calculation - it is based on a 6p difference (since then the gap has narrowed to 5p here, making the oil burner even more attractive)

ckyliu, on 17 February 2012 - 13:21, said:

The Beeb would seem to agree with you, apparently diesel in the UK has just hit a brand new record. Time for me to ditch the PD130 for a 1.4 TSI?

bbc.co.uk/news/uk-17072925

The figures are pretty simple and still clearly on the side of diesel if you do anything other than very low mileage, remember that both diesel and petrol have increased in price, and the gap has not increase (in fact probably narrowed in percentage terms).

I drive a Mazda 3 1.6 TD and have recorded an average of 53 mpg over the last 30K miles.

Over the last week I have been driving a Kia cee'd 1.4 petrol - so similar class of car - this has done a measured 41 mpg over 700 mile of very similar driving.

Mazda TD = 53 mpg = 11.77 mpLT = 85 ltr per 1000 mls. at todays price of 143.9 that = £122.26/1000mlies.

Kia petrol = 41 mpg = 9.11 mpLT = 110ltr per 1000 miles. At todays pice of 137.9 that = £151.54/1000 miles.

Therefore the fuel cost for petrol is £29.28 extra per 1000 mls.

Servicing and insurance costs will be broadly similar. Road tax may be a little more for the petrol but lets ignore that.

An equivalent diesel will cost about £1000 more to buy new but some of that will be recouped a trade in time, so lets assume the diesel will cost you £700 more over a 3 year period of ownership.

At a saving of £29.28 pet 1000mls the £700 will be recouped in 24,000 miles (£29.28x24). Therefore if you do more than 8,0000 miles a year in your 3 year ownership you are better off with the diesel.

Edited 11 March, 201214 yr by slider

With regards to the CR Roomster - I forgot to mention the tyre pressures all to spec and it has used virtually no oil from new.

Just like to report i got 56.2mpg from Guisborough to Whitby, about 22 miles of moor road with an average speed of 60mph which im rather impressed by, given theres more hills then you can shake a stick at.

I think manufacturers figures are achievable but it requires to much concentration its unreal. especially for someone who like me, who takes great pleasure in driving like im on a mission.

I think these figures are only doable if you know the road, giving you the chance to plan and anticipate and corners or hills and under no circumstances are we to use the brakes!

Just like to report i got 56.2mpg from Guisborough to Whitby, about 22 miles of moor road with an average speed of 60mph which im rather impressed by, given theres more hills then you can shake a stick at.

I think manufacturers figures are achievable but it requires to much concentration its unreal. especially for someone who like me, who takes great pleasure in driving like im on a mission.

I think these figures are only doable if you know the road, giving you the chance to plan and anticipate and corners or hills and under no circumstances are we to use the brakes!

Definite if you know the road you drive accordingly this will help mpg, also I always used to drive down hills by coasting, but after all the info on here by members it's better to leave in gear and foot of the gas, much better fuel economy and you have control

Whilst on the topic of this fuel economy and manufacterers etc...

My sister is currently looking at buying a new car, she loves the fiat 500 and has test drove practically all of the engine varients that fiat have to offer. They do a 'twin air' 900cc one which fiat claim can achieve in excess of 60mpg! My sister borrowed one for two days and didnt see any more than 50mpg, when she questioned this at the dealership fiat were not suprised. When selling the Twin Air cars, fiat are making customers sign disclaimers to actually say that they understand the figure is not accurate and basically bull****! I was amazed that they can actually do this...

Went on a little run yesterday evening about fifty miles to collect some ebay goods I'd won. Was in no rush and achieved 47.2 mpg average( on the trip computer thingy ) boring as hell so on the way back I drove it a lot faster lol ( 2002 Octy VRS ) 32.6 mpg average on return trip but lots of fun ! I also have a 1.6 cr engined Jetta as my company daily drive. Doesn't matter how hard I drive it's always about 50 mpg ! And on a run driving carefully it takes ages to better this. Conclusion I may as well drive the Jetta like I stole it !

Big thumb up to Ema_jane for firstly getting such good mpg and secondly being able to insure a VRS you only look about 18 lol.

In any new diesel car I have owned it has taken at least 10k miles for mpg to improve and then I have seen further improvement up to 20k miles, after that the mpg pretty much stays the same, changing slightly with ambient air temperature and just before and after servicing and tyre changes.

That's just one of the problems with comparing mpg figures, all the variables e.g. tyre wear, engine oil cleanliness, air filter cleanliness, fuel used (supermarket or main brand additives), weather (headwind, rain), road and traffic conditions, etc etc etc.

Went on a little run yesterday evening about fifty miles to collect some ebay goods I'd won. Was in no rush and achieved 47.2 mpg average( on the trip computer thingy ) boring as hell so on the way back I drove it a lot faster lol ( 2002 Octy VRS ) 32.6 mpg average on return trip but lots of fun ! I also have a 1.6 cr engined Jetta as my company daily drive. Doesn't matter how hard I drive it's always about 50 mpg ! And on a run driving carefully it takes ages to better this. Conclusion I may as well drive the Jetta like I stole it !

Big thumb up to Ema_jane for firstly getting such good mpg and secondly being able to insure a VRS you only look about 18 lol.

Yeah if i kick her teeth in she will return no better then 40mpg :/ i dont mind a slow drive every now and then, get abit of Smooth FM on and chill out!

Ha thanks, im 22 btw but yes she isnt cheap to insure!

On a decent A-road run, I get mid-50s at a fairly even 60mph, and kicking it when needed to get round slower traffic.

I think it depends a lot on where you live ie what the traffic is like ie heavy or next to non existent. As one of Clarkson's pearls if wisdom say if you touch the brakes you should count yourself a failure, hen went on to say he had never touched the brakes on the motorway.

Whilst the above is nigh on impossible and you alway get some Tw^t pull out out you and slow your progress, contrary to the Highway Code, this I find is the major reason for being some distance from the manufacturers figures. If you do not use the brakes ie start slowing down by coming off the throttle at the point where momentum will take you up to the next junction or lights with only a dab on the brakes in the last second before the junction the fuel consumption, I find, gets close to the manufacturers figures. Small diesel engine in a big car seem to suffer worse as they have to use a higher percentage of throttle to get back up to normal speed.

Always use to be true with Carburettored engines, and I suspect is also true for indirect and direct fuel injected cars, that the further the throttle is pushed down the "richer" the air/fuel mix is and therefore the more inefficient the engine is. In Japanese hyper miling techniques they drive with just their big toe on the throttle and try to only depress the throttle a millimeter or two and achieve one or even 200 mpg in the Insight, Prius etc. There are some brilliant engines out there, the twin charge 1.4 TSI, the VVT 1.8 TSI and now the cylinder shut of Audi, Bentley etc TSIs which will filter down to Skoda in a few years time. A long with start-stop, aluminium bodies we should be getting 80-100 mpg cars in 5 to 10 years but they will proably cost more which partly offsets the savings.

Diesels, unless there is a new breakthrough ie 2 stroke, w"nkel or something like that its days are numbered, too expensive, too heavy and takes up too much engine bay space and direct injection turbo petrol are closing the efficiency gap. The new Peugeot diesel-hybrid is getting bad reviews as expensive and not that good.

the NOT using your brake idea, is ideal.... when going for fuel economy, I will read the road well ahaead ect, and back off early, you don't loose much progress, and you make massively with the fuel economy...

just think... every time you press that brake pedal, you are wasting fuel you used to get up to speed....

I've entered the Roomster Fuelly average in to Honest John's Real MPG website (http://www.honestjoh...ufacturer=skoda). It seems my car represents the lowest end of the range at 44.5 mpg, although is only 6.7 mpg off the average figure of 51.2 mpg.

Just spoke to my neighbour earlier and it seems his TSi engined Fabia returns broadly similar mpg to my diesel Roomster!

No matter what car I am considering buying I always subtract 20% from the mfr's claimed combined figure. This usually tends to give me a realistic idea of potential mpg figures .