Misleading MPG figures from MB?

[television]

Yes my road tax is only £475

 

[L John]

Mine too, I thought it was in a lower band when I got the car but just have to suck it up.

Should have checked before but it wouldn't have stopped me buying it anyway.

BMW with similar power engines were in a lower bracket, maybe due to the ones I was looking at having a turbo.
The way I look at it is the NA Merc costs more in excise duty but will be cheaper over a ten year period than the cost of a turbo failure.

 

[television]

Yes, If I change my CL to the new blue version than I get twin turbos. Problem is the blue version is so new, we get no feedback on it yet.

One gets more info from the USA sites on these things.

 

[Beeem]

I'm glad I am not the only one struggling to get sensible MPG figures in relation to the MB figures.

This subject seems to generate a paranoia whereby the obsession with fuel consumption figures takes on nightmarish proportions.

Just make sure your car is correctly tuned and enjoy driving it. Forget about the fuel consumption or buy a smaller car.

 

[television]

This subject seems to generate a paranoia whereby the obsession with fuel consumption figures takes on nightmarish proportions.

Just make sure your car is correctly tuned and enjoy driving it. Forget about the fuel consumption or buy a smaller car.

I think you do have a point here

 

[grmc]

Just as an update, the car has now covered 4000 miles and I am seeing a *slight* improvement in figures. I'm now getting around 25-28mpg on urban routes (claimed is 39mpg) with up to 36mpg on longer journeys at a steady 70 (claimed extra urban is 54mpg).

Interestingly, this also follows an engine recall that my car underwent on 2nd January when it went in to have the stop/start looked at (because that stopped working properly i.e. not starting again after stopping - very embarrassing). It turns out that between mid November and the end of December, Mercedes had identified two issues with the car, so the fixes were applied while it was in.

The upshot is that the stop/start 'fix' didn't work as it has failed again since, so much so I no longer have any faith in it so switch it off every time I start the car. It's going in again next week but I'm getting the impression that unless a fix comes in a box from Mercedes then the dealerships really don't have much of a clue on fixing these things.

Other disappointing news is that the grip in the rear wheels is pretty much non-existent in first gear (meaning sports mode on my auto box). I don't know if it's the weather, the tyres, or the set up yet but all I can say is I would love to hear from anyone with either the same engine as me or the 400 AMG Sport petrol version of the new E Class Cabriolet (and the 19" AMG wheels) regarding their experience of the grip. It's bad in all current conditions, which have varied here from 10 centigrade to minus 2 both dry and wet. The wheels spin freely on take-off whether the tyres are warm or cold, and in the ice there is just no point bothering in driving the car. So, I'm just wondering how the setup handles the higher power in the petrol engine. In 30 years of driving I've never yet had to consider winter options in the UK, but here I am now considering it with this disappointment of a car. Mercedes' only suggestion for winter tyres is a full set of 18" wheels and tyres.

The good news on the bizarre stone chipping of the protruding sections of the spokes on one of the wheels is that three months after complaining and it looking like it has measles, Mercedes have agreed to swap the wheel. Bad news is that there are none available so I've got to wait for it for an unspecified amount of time.

I get what people are saying about "just enjoy it for what it is" but when you spend so much on something that you have a right to expect perfection with, it is bitterly disappointing when these problems take the shine off it. I work really hard for the money I earn and I like to get maximum enjoyment from the things I spend it on.

 

[Troon]

The wheels spin freely on take-off whether the tyres are warm or cold, and in the ice there is just no point bothering in driving the car. So, I'm just wondering how the setup handles the higher power in the petrol engine. In 30 years of driving I've never yet had to consider winter options in the UK, but here I am now considering it with this disappointment of a car. Mercedes' only suggestion for winter tyres is a full set of 18" wheels and tyres.

In wintry conditions you need suitable tyres. If you find wheelspin in non-wintry conditions, I think I've discovered why you don't get the published fuel economy figures.

 

[obduro]

Just as an update, the car has now covered 4000 miles and I am seeing a *slight* improvement in figures. I'm now getting around 25-28mpg on urban routes (claimed is 39mpg) with up to 36mpg on longer journeys at a steady 70 (claimed extra urban is 54mpg)

Get used to it buddy, my E350 has done 20 times your mileage and it has the same figures. :lol:

I honestly believe a car achieving the stated MPG is a myth like the loch ness monster.

 

[Troon]

I honestly believe a car achieving the stated MPG is a myth like the loch ness monster.

I average a shade better than my car's combined figure (41mpg vs 40mpg). Best-case extra-urban for mine is 48mpg, and yet... :mrgreen:

 

[ThinkPad]

I average a shade better than my car's combined figure (41mpg vs 40mpg). Best-case extra-urban for mine is 48mpg, and yet... :mrgreen:

You surely drive like a little old lady!!

(No offence!)

 

[gizze]

Just as an update, the car has now covered 4000 miles and I am seeing a *slight* improvement in figures. I'm now getting around 25-28mpg on urban routes (claimed is 39mpg) with up to 36mpg on longer journeys at a steady 70 (claimed extra urban is 54mpg).

Extra Urban is 39mph not 70.

Urban is nothing like city driving either.



Look at the US sites for their city and highway figure, much more realistic and pretty much what most achieve as owners.

 

[ThinkPad]

If you really want to know what you will achieve. Take the combines, and assume you will et 10mpg less. If you get a little more then happy days. But this rule of thumb is usually accurate for my driving style. The official figures are only for COMPARISON between vehicles, they are not for telling you what you will get. They are also tested under the eye of the Dept of Transport...so accusing the manufacturer of being misleading is just plain ignorance of the subject.

 

[Troon]

They are also tested under the eye of the Dept of Transport...so accusing the manufacturer of being misleading is just plain ignorance of the subject.

Yes, although it's "Europe" that manages it:

https://en.wikipedia.org/wiki/New_European_Driving_Cycle

 

[L John]

It's good to see how many MPG you can get on a long run. I did it once.

Since then it's been a hoot not caring, I get way more SPG driving for pleasure rather than driving to see what I can eek out of the car.
It wasn't bought for economy anyway. I'd have bought a Yaris (cough, spit) if MPG was top priority

SPG = Smiles Per Gallon and inversely proportionate to MPG

 

[grmc]

If you really want to know what you will achieve. Take the combines, and assume you will et 10mpg less. If you get a little more then happy days. But this rule of thumb is usually accurate for my driving style. The official figures are only for COMPARISON between vehicles, they are not for telling you what you will get. They are also tested under the eye of the Dept of Transport...so accusing the manufacturer of being misleading is just plain ignorance of the subject.

If you look at my earlier posts, I cover the reasons for my expectation loss there, but to repeat: In driving for 30 years and owning over 20 cars (almost all being performance petrol engined cars) in that time and achieving roughly 90% of the manufacturer's claimed figures, I would've expected, and been happy with, something like 40mpg on a combined (or overall) use of this car. As it is, I'm getting just under 30mpg overall. Given that every car I've owned I've made my manual mental adjustments based on experience, I don't think it it is unreasonable to expect the same sort of consistency, do you? This also means it has been (and ought to continue to be) a satisfactory means of comparing across the range, as I did for the previous two petrol Mercedes I owned and indeed did when deciding whether or not to have the petrol model of the car I ended up buying.

Having successfully applied the method for so long, I don't have to expect to suddenly start adjusting my expectation based on some folklore found on the internet in forums concerning the differences between claimed and actual mpg for diesel engines - I'd expect that sort of difference to appear as a disclaimer in the advertising materials or a warning from the salesman, and it doesn't. In fact, the discussions on fuel efficiency and the relative merits of the petrol vs diesel consumption were discussed at length before placing the order for the car. I think it's therefore harsh to say this is down to "just plain ignorance".

 

[MBDevotee]

If you look at my earlier posts, I cover the reasons for my expectation loss there, but to repeat: In driving for 30 years and owning over 20 cars (almost all being performance petrol engined cars) in that time and achieving roughly 90% of the manufacturer's claimed figures, I would've expected, and been happy with, something like 40mpg on a combined (or overall) use of this car. As it is, I'm getting just under 30mpg overall. Given that every car I've owned I've made my manual mental adjustments based on experience, I don't think it it is unreasonable to expect the same sort of consistency, do you? This also means it has been (and ought to continue to be) a satisfactory means of comparing across the range, as I did for the previous two petrol Mercedes I owned and indeed did when deciding whether or not to have the petrol model of the car I ended up buying.

Having successfully applied the method for so long, I don't have to expect to suddenly start adjusting my expectation based on some folklore found on the internet in forums concerning the differences between claimed and actual mpg for diesel engines - I'd expect that sort of difference to appear as a disclaimer in the advertising materials or a warning from the salesman, and it doesn't. In fact, the discussions on fuel efficiency and the relative merits of the petrol vs diesel consumption were discussed at length before placing the order for the car. I think it's therefore harsh to say this is down to "just plain ignorance".

I think what you're forgetting is that manufacturers are getting better at "faking" the figures.

Because these "official" tests are SO important to sales, manufacturers program the ecu's to get the absolute max they can on them, often to the detriment of real world economy.

As time goes on, the difference between the "official" MPG and the actual will get more and more...

 

[L John]

Honest Johns real MPG

 

[gizze]

If you look at my earlier posts, I cover the reasons for my expectation loss there, but to repeat: In driving for 30 years and owning over 20 cars (almost all being performance petrol engined cars) in that time and achieving roughly 90% of the manufacturer's claimed figures, I would've expected, and been happy with, something like 40mpg on a combined (or overall) use of this car. As it is, I'm getting just under 30mpg overall. Given that every car I've owned I've made my manual mental adjustments based on experience, I don't think it it is unreasonable to expect the same sort of consistency, do you? This also means it has been (and ought to continue to be) a satisfactory means of comparing across the range, as I did for the previous two petrol Mercedes I owned and indeed did when deciding whether or not to have the petrol model of the car I ended up buying.

Having successfully applied the method for so long, I don't have to expect to suddenly start adjusting my expectation based on some folklore found on the internet in forums concerning the differences between claimed and actual mpg for diesel engines - I'd expect that sort of difference to appear as a disclaimer in the advertising materials or a warning from the salesman, and it doesn't. In fact, the discussions on fuel efficiency and the relative merits of the petrol vs diesel consumption were discussed at length before placing the order for the car. I think it's therefore harsh to say this is down to "just plain ignorance".

But petrols seem to be far more suited to the tests.
They warm up far quicker for a start, diesels can take 30 minutes to get to temperature, so if you do lots of sub 30 minute journeys it can cripple your mpg average.

 

[whitenemesis]

I think what you're forgetting is that manufacturers are getting better at "faking" the figures.

Because these "official" tests are SO important to sales, manufacturers program the ecu's to get the absolute max they can on them, often to the detriment of real world economy.

As time goes on, the difference between the "official" MPG and the actual will get more and more...

IIRC from reading the EU directive on this, two vehicles are used in the official tests and are selected at random from the production line by the independent test lab.

 

[exjag]

It's a while since I started reading this thread which is now quite long, but despite all the criticism, I do not recollect anyone on here coming up with a reliable alternative method. Perhaps because there isn't one?

As has been said, the method used ensures a reliable and undistorted comparison between makes and models - undistorted by the vagaries of weather, cold engine, warm engine, heavy foot, light foot, topography et al.

I notice that in newspaper adverts manufacturers have catered to the punctilious by stating that figures are for comparison purposes only, though this will probably not assuage the unrealistic nitpickers amongst us.

"It should be noted that as the fuel consumption figures quoted are obtained under specific test conditions, they may not be achieved under ‘real world’ driving conditions. However, the figures serve as a means of comparing models of a similar type." (Directgov. website).

"My vehicle does not produce the same fuel consumption figures as shown in the 'New Car Fuel Consumption and Emission Figures' publication and/or the Internet site?

Because of the need to maintain strict comparability of results achieved by the standard tests they cannot be fully representative of real-life driving conditions. Firstly, it is not practicable to test each individual new car; thus only one production car is tested as being representative of the model and may therefore produce a better or worse result than another similar vehicle. Secondly, there are infinite variations in driving styles and in road, car and weather conditions, all of which can have a bearing on the results achieved. For these reasons the consumption achieved on the road will not necessarily accord with the official test results." (dft.gov.uk website)

Where's the fakery??

Does it really matter? Does anyone buy or not buy a car because of the fuel consumption figures? Motoring must be a nightmare for those whose ownership revolves around such minutiae.

http://cars.uk.msn.com/exclusives/extreme-fuel-economy-how-green-could-your-car-get