http://www.dailymail...on-figures.html

Which? tested some cars true mpg against the manufacturer claims. The super eco cars came off as having the biggest difference between the tested figues and the claimed figures.

Tests carried out by two 'engineers' on a fixed route.

I'd have liked to have seen the tests replicated on some other cars (like a vRS) to see if the ratio between claimed/tested changes with other car types. Might be more accrate on cars that are not built for economy.

Either way the Kia figure is pretty bad. I can get a calculated 37.5 from my TFSI without too much effort and I know which would be more pleasent to drive.

Edited 27 April, 201214 yr by Aspman

Autocar did a similar thing, pitched a Range Rover and a BWM 320d ED and some other "eco" cars against each other - the eco cars were further away from their official MPG than the big engined cars.

Eco cars are engineered to do well on the Euro tests, and nothing else!

Eco cars are engineered to do well on the Euro tests, and nothing else!

Yup! couldn't agree more.

That's why I would not want one. Yes I can get a car that has an advertised 70+mpg but you can guarantee that with four adults with luggage on a trip to Germany would see rubbish MPG and would not get us anywhere near 100mph comfortably!

Plus to get the claimed MPG on a motorway with most of these eco cars you have to drive at 55-60! Yeh right... no thanks!

Yeah, the other problem is, take my vRS vs a 1.0 Kia...

On a flat, straight road, the Kia will use much less fuel, however, my vRS will use not much more fuel than it normally does when the road starts going up an incline. The Kia will need much more throttle input to do it, which will destroy the economy! This is what the Autocar article said, basically.

Yeah, the other problem is, take my vRS vs a 1.0 Kia...

On a flat, straight road, the Kia will use much less fuel, however, my vRS will use not much more fuel than it normally does when the road starts going up an incline. The Kia will need much more throttle input to do it, which will destroy the economy! This is what the Autocar article said, basically.

Yup. Also the same story with carrying more weight or accelerating onto a dual carriageway. You would have to hammer it to get going properly. In a more powerful car you can achieve the same/better acceleration and not have to work the engine as hard and therefore use less fuel in the long run.

Plus it's just not as enjoyable. I have had smaller engined cars and having to really work it to get up a hill really isn't pleasant.

Exactly, it's easier to maintain momentum in a more powerful car. Although motorway sliproads are fun to wind up most cars to the red line

Slip roads, with a slight upward slope are great fun

That's why I would not want one. Yes I can get a car that has an advertised 70+mpg but you can guarantee that with four adults with luggage on a trip to Germany would see rubbish MPG and would not get us anywhere near 100mph comfortably!

I can confirm that the Cooper D will do 100+ mph effortlessly and the mpg it returns isn't too shabby. Not sure about fitting 4 adults *and* their luggage in it though Over 25k miles, I averaged about 55mpg (19 shy of the book figure!) but I tended not to drive it in the most economical fashion.

BMW/MINI seem to be the only manufacturer who produce eco models with some sporting credentials, rather than the uninspiring low-power poverty spec "green" offerings from other manufacturers.

Chris

Slip roads, with a slight upward slope are great fun

Yes... Especially if there a 2 lanes with some slower cars in the left lane

I can confirm that the Cooper D will do 100+ mph effortlessly and the mpg it returns isn't too shabby. Not sure about fitting 4 adults *and* their luggage in it though Over 25k miles, I averaged about 55mpg (19 shy of the book figure!) but I tended not to drive it in the most economical fashion.

BMW/MINI seem to be the only manufacturer who produce eco models with some sporting credentials, rather than the uninspiring low-power poverty spec "green" offerings from other manufacturers.

Chris

2 adults in the front and their luggage in the boot.

Squash another two onto the back seat and place any further bags on top of them.

Squash it all down a bit.

Simples

The super eco cars came off as having the biggest difference between the tested figues and the claimed figures.

According to the table the eco cars were closest to the manufacturers claim

Prius 'only' 18.4 mpg difference while Kia had 26.1 mpg difference

But is that in the PSA engined (I think) Cooper D, as this was updated fairly recently ? Rumour is the current BMW diesel is less efficient, but smoother.

RBW.

I can confirm that the Cooper D will do 100+ mph effortlessly and the mpg it returns isn't too shabby. Not sure about fitting 4 adults *and* their luggage in it though Over 25k miles, I averaged about 55mpg (19 shy of the book figure!) but I tended not to drive it in the most economical fashion.

BMW/MINI seem to be the only manufacturer who produce eco models with some sporting credentials, rather than the uninspiring low-power poverty spec "green" offerings from other manufacturers.

Chris

But is that in the PSA engined (I think) Cooper D, as this was updated fairly recently ? Rumour is the current BMW diesel is less efficient, but smoother.

Mine was the BMW engine which has a higher book economy (74mpg) and lower emissions (99 g/km), but reading around the forums it seems that it's easier to achieve better figures in the old PSA engined one. Driving them back to back, the BMW engine is significantly better with more power, refinement and much smoother delivery and I was happy to sacrifice a bit of economy for a better driving experience

Chris

I remember Evo did something like this between the Prius and a Panda 100HP. They conducted it in town, on a motorway, fast A-road and a B-road.

The difference in economy was apparently negligible, but in the Prius's favour. The differences in price really averaged it out. You'd have to drive circa 1,100,000 miles before you got your money back!

The real world fuel economy will depend on many factors, but the thing anyone looking at a car with fuel economy in mind needs to consider is what they are going to use it for.

My last three driving school cars have been quite different:

Skoda Fabia VRS 1.9, this car managed a real world 45mpg across the year in a mixture of driving. It was less good on the learner urban pottering, but made good fuel economy on the motorway / dual carriageway drives. If you chose to cruise at a more "making progress" kind of speed, the car was the most economical of the three.

Mini Cooper D (with the PSA shared engine), this car managed a real world 52mpg across the year. Definitely more economical than the Fabia on the learner urban pottering, On a motorway cruise at 70mph, it would return a genuine 68mpg. Wind it up to a "making progress" pace though and it would drop into the low 40s / high 30s. The Fabia was better for this sort of thing.

Latest car is the Kia Rio 2 with 3 cylinder 1.1 CRDi engine. So far it is returning a real world 56mpg (started low but as it loosens up it is improving lots) and in the learner urban pottering it is considerably better than the Mini. On the other hand, a 70mph dual carriageway drive is not too great returning around 60mpg. "Making progress" cruising kills the economy completely, I have not figured it yet, but it is not going to be as good as the Mini or Fabia. The Rio has only covered just over 2000 miles, so more to come from it in economy terms I think.

All three cars are used in the same way. The differences between the economies are a result of how close to optimal use the car is being driven. If you want to get good economy at speed, an engine suited to that will give a better result than one optimised for urban driving. The Fabia was definitely the best for fast cruising, the Rio has had one day where I did nearly all urban driving in residential areas and managed a real world 65mpg, so obvously optimised for this kind of work.

The other thing to consider is the options list. Those wide tyres on alloys can really suck the fuel. A move from 185 to 195 section tyres could easily cost you 10% or more on fuel bills in a small engined car. Of course, the way you drive has a big effect too. The turbo'd MR2 roadster managed around 48mpg on a recent 250 mile cruise up to Liverpool. Shortly after this, an early morning jaunt on the Isle of Man saw closer to 15mpg!

Chris

'BBC news 24' / Breakfast BBC this morning'

are running the story showing 'What Car' doing the MPG road test with their equipment.

The 'Yellow' Focus doing the test with the equipment fitted is driving on the test with its rear Number Plate obscured.

Thats Clearly 'clearly not visable'.

Cant believe they were doing that and showing that.

*no extra number plate like they would often tell you is needed with a bike carrier fitted.

so easy to have done, but that is What Car for you.*

'What Car' does write some properly sharn articles and their tests are often pure fiction. JMO.

george

Edited 28 April, 201214 yr by sk4gw

Erm...

Rambling posts dont require points do they?

Why do you ask?

george

I could read and understand each of the words you wrote. But as a whole paragraph of text, it might as well have been in Sanskrit :wonder:

I can understand what you are saying,

, you are probably best sticking to Picture Books & comics then.

george

Well that's probably because I am using sentences which make grammatical sense. It's a service I provide.

Rambling posts ramble, or then they are just posts.

I thought every smart arse that likes to put up their post count would know that!

george

I *think* the point is that when a publication do tests with such little attention to detail as to drive along with an obscured numberplate (is this an actual offence?), can their results really be trusted? But then they could have been doing it on a private track/runway/whatever where a plate wouldn't be required to be visible and it would be easier to reproduce the conditions vs picking a particular stretch of public road and trying to do a repeatable test in real-world traffic, so maybe the point is that George has missed the point. In short, I dunno, but I do love a good ramble.

or it could just be an anti cloning device...

I think the lesson here is that the published lab figures are basically not worth the paper they are printed on.

Whether Which? is a fit company or not to dispute these figure is open to debate but it's unlikely that the figures thay have produced are totally wrong.

Chris GBs figures are probably as accurate as Which?

If the Beeb or Which? actually wanted to be useful they should pojnt people at Fuelly or Spiritmonitor or even honestJohn's mpg figures.