Now she's nicely run in (7500 miles) and given the light traffic of the school holidays, I thought it was time to see if this 68.9 mpg was actually possible in real-world driving. So, a week ago Saturday, I brimmed the tank, zeroed the trip and fuel computer, engaged ECO PRO mode, and have since driven gently, followed the shift indicator's advice, and otherwise driven my normal commute at the most sedate pace I can manage. This means a cruise controlled 60 mph (occasionally 70) on the motorway, no hard acceleration, and as close to mimsing as my conscience will allow. I have also enjoyed near perfect traffic conditions, and two non-rush hour pootles up to Oxford.
The result? I filled up tonight after 553 miles, with the gauge sitting at just over the quarter mark, and the computer reading 67.2 mpg average, and a 227 mile remaining range. Same pump at the same garage that I last filled up at, stopping at the second click. Total fuel added was 39.69 litres, which by my remedial maths, makes a genuine 66.2 mpg. So, not only was the computer remarkably close, but I proved that the EU figure is really not something you can expect to achieve even in near perfect conditions, and when driving like a nun.
That said, it got a lot closer than I was expecting. Had my fill of driving slowly for a while, but I think I might repeat the exercise in another few k and see if extra loosening of the engine improves matters. :-)
Cheers
DP
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So my maths says 39.69 litres = 8.74 gallons. So over 553 miles you got 63.26mpg. Not as good as you worked out but not bad.
How much worse if you drove it normally though?
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Just verified your maths on my calculator and you are of course spot on. Not sure where I went wrong. Oops.
Normal driving gives about 53.
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Even 53mpg is not bad at all for a car thet can still shift quite well. The extra 20 or so bhp that is available in the 5 series (and non ED 3 series) is fun to have though...
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>> Now she's nicely run in (7500 miles)
Its not, really its not, not by some margin. Do it again at 20k. Diesels take an age to fully run in when it comes to MPG
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The fuel figures are impressive and I don't think any car ever gets very close to the EU published figures. May we be told how the gentle and economical driving style affected the journey time?
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Brim to brim isn't an accurate way to measure fuel consumption. You need to measure it over a reasonable length of time ~ at least a month ~ and even then there will be significant differences from one month to another depending on journeys, driving style, weather etc.
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>> Brim to brim isn't an accurate way to measure fuel consumption. You need to measure
>> it over a reasonable length of time ~ at least a month ~ and even
>> then there will be significant differences from one month to another depending on journeys, driving
>> style, weather etc.
>>
Of course L'es, but that wasn't the point of the exercise. I wanted see if I could achieve the combined figure over a single tankful. Any variation from this tankful would almost certainly be downwards, as I really have had a perfect 10 days for traffic.
If it didn't give me my 68.9 here, it's simply not going to outside of test conditions.
Journey times are interesting. The difference is next to nothing. Couple of minutes tops.
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Chap in the village has one of these - he reckons on between 55 and 60 - but he does drive like fart. My FiL has a 328 (petrol) version - he drives it as if he stole it and gets 41mpg. He managed to get it down to 17mpg on the test drive.
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DP's test was valid enough, l'Es, especially since he was careful to use the same pump before and after. Your point is that one tankful measures only the driving and the conditions at that time, but that's precisely what DP wanted to show: that even under artificially ideal conditions the car can't quite achieve its Combined figure. He's already told us that his longer term consumption is much higher.
You and I are both on record that our early-2000s cars regularly exceed their Combined figures. More recent cars, it seems, never do. Here's what I think is going on: you have a latish example of a model launched in 1998, when CO2 measurements were new and poorly understood. I have a 2002 example of a car launched in 2000, whose diesel engine came along in 2001; still early days and in the Euro 3 era.
Since then I've also had and measured two 2008-09 Euro 4 diesels with engines launched in 2006, by when manufacturers had had time to get better at massaging engines to achieve optimal test - and therefore sales - results. Neither has achieved its Combined figure in my care, but neither was that far off, typically 10 percent or so.
Now we're on to Euro 5 and manufacturers and buyers are all looking at the CO2 output before almost anything else, so the massaging is more intense than ever. There have been genuine advances - DP's 53mpg average from a biggish four-seater is appreciably better than the 45 I get from my similarly sized 2002 car - but buyers have come to think of the Combined value as being achievable and are understandably disappointed when it proves not to be.
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It's worth reading the actual MPGs just to realise someone in the Treasury will be boiling at the lost revenue. 53mpg = 142/143 g/km putting the car in band F for VED.
Multiply that by the number of 3 series sold and up for the c.1.9 to 2 million cars registered per year.
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Doesn't work that way, though, does it, Gmac? Taxation is a balloon: squeezing one end will make it bulge somewhere else. The relative tax breaks on low-CO2 vehicles will have been calculated as part of the overall required tax take, and other rates adjusted accordingly. Nobody in the Treasury will give a damn, provided they bring in all the tax that's due.
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>> The relative tax breaks on low-CO2 vehicles will have
>> been calculated as part of the overall required tax take, and other rates adjusted accordingly.
>>
That would depend on when that calculation was made.
These bands were calculated mid-00's when life was good and money was available. Since 2009 it's changed, manufacturers have learnt how to optimise and the Government can't seem to find enough places to generate income.
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I agree that the older engines had no trouble meeting their combined figures. Our ten year old PD engined Golf gets within 1 mpg of its combined 53 mpg, despite 130,000 miles of wear and tear, and spending a lot of its time doing short runs, or hopping around town. It has proven its ability many times in the past to return genuine mpg figures in the low 60's over a tankful given long runs and gentle treatment. And all this without the BMW's regenerative braking, and fancy engine management modes that tweak accelerator mapping and air-con output. OK, the BMW is over 30 bhp up, and is noticeably quicker, but not by the amount that ten years of progress might indicate. The VW has no DPF of course, and is a good 100kg lighter, which helps.
I think the manufacturers learning how the tests work, and optimising the engine management system to deliver optimum results in those conditions is probably the most logical explanation for the increasing gap between what is claimed, and what is real. I don't doubt if VW submitted a suitably tweaked mk4 Golf GT TDI 130 for the EU tests now, they could manage to wind up with results of sub 110g/km CO2 figure, and 60-something combined mpg.
All this also makes me wonder whether remapping diesels is now more relevant than ever, given that they are clearly tuned very carefully to perform well in a single set of tests which bear no relation to the real world in which people use the cars. The 320d drives really nicely as it is, don't get me wrong, but if it were completely optimised for real world use, I wonder how much more efficient it could be made when used in typical day to day road conditions.
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Fancy a nice little used 3 series Dave, sublime chassis and engine......37mpg...!
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Brim to brim is pretty inaccurate. The more sensible approach - which is just as easy - is to watch for when the gauge crosses the half-way marker (or three quarters, or one quarter). You'll be surprised to find that you can gauge that point to within about 5 miles, which is 1% of your 500 miles between refuelling. Measuring twice gives you a 2% margin of error.
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>> Brim to brim is pretty inaccurate. The more sensible approach - which is just as
>> easy - is to watch for when the gauge crosses the half-way marker (or three
>> quarters, or one quarter). You'll be surprised to find that you can gauge that point
>> to within about 5 miles, which is 1% of your 500 miles between refuelling. Measuring
>> twice gives you a 2% margin of error.
>
I have to say, I can't see how this can be as accurate as measuring fuel added via a pump which is subject to a legally enforced -0.5% - +1% tolerance between the fuel volume displayed and charged for, and the actual volume it has dispensed. And using the same pump twice must reduce this potential inaccuracy even further.
In any case, it is all measured against an uncalibrated odometer, so that is almost certainly the weak link in the calculation. Although I suspect it is at least consistent.
Last edited by: DP on Wed 1 Aug 12 at 10:01
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You'll never achieve what they do in the official tests. It's on a rolling road for starters. And there is a period when the car is 'stationary' in the test so if you've got stop/start the engine is off.
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>>It's on a rolling road for starters
Why is that a problem?
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...Why is that a problem?...
No wind resistance.
Cue long and intellectually suspect series of posts about the force needed to move a given mass. :)
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>>No wind resistance.
Let's get rid of this myth.
Aerodynamic drag is first measured on a representative vehicle, and then added to the resistance provided by the rollers of the dynamometer during the testing. Aerodynamic drag is thus fully accounted for in the testing.
Phrased another way, that the test is done on rolling roads, in a lab, is not in any way a fault or flaw in the testing.
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>> You'll never achieve what they do in the official tests. It's on a rolling road
>> for starters. And there is a period when the car is 'stationary' in the test
>> so if you've got stop/start the engine is off.
>>
Not only is it on a rolling road, the car's tyres are pumped up to the maximum the tyre will allow, to reduce rolling resistance further - wouldn't fancy driving it on the road like that; oh and the acceleration profile is so gentle that a turbo won't kick in. It's about time these tests were made a bit more real world.
My 53 plate 1.8 Astra G does a real world 45+ mpg at this time of year, which is presumably pretty close to the official combined figure (which I can't find) - but that's a mid 90s design car presumably.
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>> My 53 plate 1.8 Astra G - pretty close to the official combined figure (which I can't
>> find)
Taken from a 2002 handbook.
i.imgur.com/mNN0Pyy.jpg
You'll have to work out the mpg as it's displayed in l/100km
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snipquote!!
>> You'll have to work out the mpg as it's displayed in l/100km
>>
So, using Mark's link, as I'm too lazy to get me calculator out, 6.1l/100Km is 46 mpg, which is pretty much spot on.
Last edited by: VxFan on Fri 19 Jun 15 at 12:53
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>>
>> In any case, it is all measured against an uncalibrated odometer, so that is almost
>> certainly the weak link in the calculation. Although I suspect it is at least consistent.
>>
>>
>>
And since most odometer over-read by 2-5%, almost no car stands a chance of achieving published figures. EVER. In reality.
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I never said it was a flaw in the test - just commenting on them not doing it on a road. But if they did it would be too difficult to compare two tests. But the issue is the test does not represent reality but it does provide a valid comparison between different cars.
To prove how the driver makes a huge difference, Auto Express did an article on the tests done for CO2 emissions. They drove a car (a Golf Bluemotion I think) and managed to improve their figures over time but did not get the official figures even when doing the actual test. The official test driver did however which proves it is difficult to get the official figures even in the official test environment!
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Yes, you didn't say there was a flaw, but, you did say "It's on a rolling road for starters"
What did you mean "for starters"?
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That it's not done on a real road with all that brings like different road surfaces, camber, speed bumps, pot holes... it's not a real road.
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>>different road surfaces, camber, speed bumps, pot holes...
So, the rolling road is actually removing aspects of real roads which could make the results invalid for comparison. It's not a reason why people can't acheive the published figures.
More realistic differences between the published figures and reality include;
- gradients
- traffic conditions
- weather conditions
- driver response
- vehicle prep - tyre pressures at the ECO setting - windows, AC, etc
- vehicle optimization for the test
- uncalibrated instruments
- uncontrolled fuel
Last edited by: Number_Cruncher on Wed 1 Aug 12 at 12:05
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Weight of the driver, passengers, and luggage too will make a difference won't it?
And the cars are warmed up before the tests begin which takes time in the real world, especially for diesels.
Don't get me wrong the tests are a good way of comparing cars - just don't expect to get the MPG figures they publish.
You mention tyre pressures... these go up/down in the real world depending on the ambient temperature. In very cold weather mine would be down a bit until warmed up. But if you put more air in them then they could go over the proper pressure when warmed up.
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>> This is interesting...
>>
>> www.theicct.org/sites/default/files/publications/ICCT_EU_fuelconsumption2_workingpaper_2012.pdf
>>
Thanks for that, it is indeed interesting - a 21% difference between real world and defined test cycle
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>> Wed 1 Aug 12 14:21
>> Fri 19 Jun 15 17:18
Just sayin'
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Just to provide a relative figure, this morning I engaged Sport mode, and drove the car normally on the same commute in the same traffic conditions. Two observations:
Computer read 60.2 mpg. This is a little over 10% lower than the same reading when driving during the test. I know the absolute figures on the computer can't be taken as read, but the comparisons are valid.
Second observation - Jeez, it feels quick! :-)
Cheers
DP
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When I've driven longer distances in my car I know driving slower means more MPG and not getting there much later. But it's not as much fun and as a percentage difference to cost I usually decide to drive how I want to. Over 3 years I am sure I could save lots if I drove no faster than 56mph on motorways.
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>> Keep it on sport..!
>>
I intend to! :-) Also, as I have a fuel card, saving money is not a consideration. The exercise was inspired by simple curiosity.
I'd almost forgotten how lovely that 4th gear surge felt when joining the motorway. Legs stretched very nicely this morning on near empty roads. :-)
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>>Legs
>> stretched very nicely this morning on near empty roads. :-)
Yup like me yesterday, nearly empty road, just me and the cop car
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>> Yup like me yesterday, nearly empty road, just me and the cop car
>>
Heh heh. I did consider that myself this morning. Didn't go mental. It's amazing what feels quick and enjoyable after ten days of eco-purgatory.
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My 120d is incredibly temperature dependent. Over the winter I averaged 43mpg; it's now up to 49 and a similar hyper-miling approach last week when it was 29C outside achieved 56mpg. Book figure is 64.
Would not buy another BMW. My dad's Skoda Superb estate does the book figure or better regardless of the weather.
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Hmmm. Part of me wishes I'd persevered with the Superb. The LEC struggles to average 36 against a Combined of 39. Which engine and gearbox does Polecat Pater have?
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"The LEC struggles to average 36...."
That isn't good news, WdB: I can get that easily on a long run in my petrol Octavia estate (which has the Mark V Golf GTI engine), although more like early 30s on short journeys. The diesel vRS I had before this one did about 15 mpg better.
My first and last German taxi, a B200CDI, averaged 39 mpg, so maybe Mercedes engines have a problem in this area? Hopefully Humph may see this: he does a lot of long journeys in (I think) a similar car to yours, WdB, so may have a better average.
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>> Hopefully Humph may see this: he does a lot
>> of long journeys in (I think) a similar car to yours, WdB, so may have
>> a better average.
Nah, he's always trying to hang the tail out.
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Does depend on what averages are being compared though Avant - we have an A4 with the 2.0T engine which I assume is similar to that in your Skoda. It will do 38ish mpg on a long journey if you take it easy, though it's more likely to do 35ish. But the overall average over 50k miles has been a touch over 31mpg.
My estate car, which I think has the same engine as Humph's but mated to a 7 speed auto 'box, has averaged 50.5mpg on a couple of long runs recently - one from the south coast to Yorkshire, and one a European jaunt. Mind you, another 'pressing on' journey to Yorkshire was completed at an average of under 40mpg, though in considerably less time.... It's average since new is 'only' a fraction over 41mpg. I'm happy enough with that especially given I don't do that many long journeys - my week day mileage is around 30 miles a day.
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Peter and Humph have the current-model LEC with the Blue Efficiency engine - same 2.15-litre block but different injectors and turbo, or even turbos. Theirs certainly have better official figures than my 2009 car but they're also Euro 5, which tends to widen the gap between test and reality.
I suspect my disappointing return has more to do with southeastern traffic: automatics don't appreciate being stuck in queues, and I would certainly have seen the value of stop-start as I crept past Monday's accident on the M4. My best single tankful was for a long run up the west coast of France, which gave 38.5 despite a full load of people, luggage and bikes. I've seen as much as 45 (more like a true 43) on the computer, but never managed to sustain that sort of gentle, unimpeded driving for 500 miles between fills. The old Volvo does 45 all the time.
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My first post run-in average tank return was 49 mpg. Since then it's been consistent 52-55 mpg returns, even with spirited use, and the odd M25/M3 howler thrown in to the mix. Average when I last checked was running around 53. something mpg, although the last tankful will up that a bit.
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>> Would not buy another BMW. My dad's Skoda Superb estate does the book figure or
>> better regardless of the weather.
Forgive me, but is that the only reason you bought a 1 series? The fuel economy? Not the handling? There aren't many cars around that do the book figure.
There is a large thread on Pistonheads about Volvo S60 D5's. General concensus is to buy a Euro 3 car. The later Euro 4's can't touch the earlier cars for fuel economy because all the extra emissions control equipment is now making the engines less efficient.
And so it is with other modern diesels. It would be more useful to keep the weight down.
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>> >> Would not buy another BMW. My dad's Skoda Superb estate does the book figure
>> or
>> >> better regardless of the weather.
>>
>> Forgive me, but is that the only reason you bought a 1 series? The fuel
>> economy? Not the handling? There aren't many cars around that do the book figure.
>>
>>
>> And so it is with other modern diesels. It would be more useful to keep
>> the weight down.
>>
>>
>>
No, it's because I feel blatantly lied to. Had it missed the figure by 10% I wouldn't care but to undershoot by 30% or more suggests some impressive dishonesty at the highest levels of the company.
And, as others have pointed out, it's also a tax dodge on a massive scale.
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Biggest winners of the 'tax dodge' are the customers.
I can't believe you've been around car forums for as long and are unaware of the perennial fuel economy nonsense.
Start-stop systems are over-represented in the economy tests so improve CO2 figures far more than the average driver will notice - BMW were early adopters of this tech.
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>> Biggest winners of the 'tax dodge' are the customers.
>>
Those customers being ?
It would be interesting to see a typical customer breakdown of such models. Private individual or big business ?
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gmac, you're missing a significant point here. As a company car driver you benefit as an individual from lower emissions because of Benefit in Kind. The company also benefits in other ways. You don't even need to be working for a big business.
Lets say two cars I might have looked at were the Skoda Superb Estate Elegance 170PS and Passat CC GT 170PS. A comparison I did... I wanted the latter but the former would have been very nice and list price was lower. It had higher emissions and not such a good deal for the lease either.... end result was the Passat CC GT was cheaper.
Earlier last year the new 5-series was a bargain but well before I could order. And then it went up about £80+ per month. And having sat in that 5 series the old/previous 3 series was not a consideration.... the new one is very nice.
If the rear lights of the concept/next Mazda6 are not as I have seen.... tempted by the new Mazda6 in 2014. If it's still on the list. And I had the Mazda6 diesel everyone complains about but I avoided issues.
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The BiK is not lost on me rtj70, and again I agree you don't have to be working for a big business but can put such a vehicle through as a co. car working for yourself.
Question is: Are people spending more than a years average salary financing these through their own pockets or are they appearing on a balance sheet elsewhere ?
These eco/efficient/LEV vehicles tend to be the other side of £30k. Who spends more than the average UK income (£24k last time I looked) privately financing such a vehicle and how many are financed in other ways ? Who then gets the benefit ?
Last edited by: gmac on Thu 2 Aug 12 at 07:37
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>> >> Biggest winners of the 'tax dodge' are the customers.
>> >>
>> Those customers being ?
>> It would be interesting to see a typical customer breakdown of such models. Private individual
>> or big business ?
>>
I would imagine a fair number are bought by people opting out of company cars. Certainly the colleague I mentioned in the OP first thread is thrilled that his is doing 60MPG in 'normal' (for him that his typical day would be a motorway runs of 2-400 miles) use.
With his mileage allowance and tax rebate, we worked out he's getting £16.80 back for every gallon of fuel used. Of course at least some of that £10 or so has to go towards the extra cost of running the car brought by doing 30K/yr.
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>> Start-stop systems are over-represented in the economy tests so improve CO2 figures far more than
>> the average driver will notice ............
If, and when, I get a start-stop car I'll disable the function whenever pssible. As for CO2 figures I doubt if I'll give them more than a cursory glance before forgetting all about them completely.
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>> As for CO2 figures I doubt if I'll give them more than a cursory glance before
>> forgetting all about them completely.
I remember mine when I have to pay car tax of £270 for a 2 litre car :(
Last edited by: Focus on Thu 2 Aug 12 at 10:29
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>> If, and when, I get a start-stop car I'll disable the function whenever pssible.
My car has a stop-start system, which I was ambivalent about when I bought it. Still am to be honest. However, though it's easy enough to deactivate (one button press per journey) I never actually do. It works seamlessly IME, but being a 4 cylinder diesel it is obvious enough when it cuts in or out. There's just no point turning it off. Mine is an auto though, which might make a difference?
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>
>>
>> No, it's because I feel blatantly lied to.
Mo. You were not lied to. You were ignorant and did not read the small print .
I am surprised anyone on this forum is so ignorant of the motoring facts of life but I suppose we all find the odd virgin here and there...:-)
Last edited by: madf on Wed 1 Aug 12 at 20:39
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FF>>And, as others have pointed out, it's also a tax dodge on a massive scale.
No, because it's all relative. Good cars are in the top band, very bad cars in the bottom band. They're all measured in exactly the same way.
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>> I never said it was a flaw in the test - just commenting on them
>> not doing it on a road. But if they did it would be too difficult
>> to compare two tests. But the issue is the test does not represent reality but
>> it does provide a valid comparison between different cars.
>>
As the link NC posted shows, it's not even much use for comparisons, because different manufacturers may bend the rules to different extents.
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WdB: our early-2000s cars regularly exceed their Combined figures. More recent cars, it seems, never do.
. . . in 2006, by when manufacturers had had time to get better at massaging engines to achieve optimal test - and therefore sales - results. Neither has achieved its Combined figure in my care, but neither was that far off, typically 10 percent or so.
Now we're on to Euro 5 and manufacturers and buyers are all looking at the CO2 output before almost anything else, so the massaging is more intense than ever. . . .
I'm sure that you're right.
Once upon a time, manufacturers didn't worry much about mpg figures. But as soon as the government decided to use emissions figures (which are, of course, closely related to fuel consumption) to set VED rates, and customers started taking VED rates into account when buying new cars, things changed, and manufacturers started using every trick in the book to get their emissions (and fuel consumption) figures down.
I have been successful in achieving (and exceeding) the combined mpg on every car I have owned in recent years. But then my most recent car dates back to 2007.
What does interest me is that with my previous (petrol) Berlingo, which dates to 2002, I was averaging over 43 mpg, which is about 13% better than the quoted combined figure. With my current diesel Berlingo, I'm averaging about 57 mpg, which is only about 9% better than the combined figure. But if I was to get a brand new Berlingo, I doubt that I would achieve that.
That said, I suspect that those vehicles which are marketed as being particularly fuel efficient models, where the "massaging" is particularly intense, are the ones where drivers have the least chance of achieving the published figures.
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>> But as soon as
>> the government decided to use emissions figures (which are, of course, closely related to fuel
>> consumption)
Very closely - simple calculation according to this:
www.eta.co.uk/2010/02/22/calculating-car%E2%80%99s-co2-emissions-its-mpg
Although does that apply to post-2001 cars as well? That is, although the figures are on the log book for modern cars, have they been calculated the same way? Or have they actually been measured?
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When I buy a car I just accept whatever the fuel consumption turns out to be. I admit I keep records of all the fuel I buy and I calculate the fuel consumption for each month and overall since I got the car but it's only because I like keeping records. So far, without trying, I've always achieved an overall consumption better than the government figure but it wouldn't bother me if I didn't.
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Ok, but once you get above 185g/km of CO2, it starts doing scary things to your VED rate . 165 will become 155, and then 145 etc over time as the govt seeks to reclaim lost revenue. High CO2 outputs will be progressively hammered harder by the taxman.
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The new Volvo is very poor on fuel. Book figure of 62, trip claims 46, but brim to brim shows 43.5.
I would put this down to me, but the C5 claimed 54 and returned an average of 51 during its time with me
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well as a regular commute of 25+ miles mostly dual carriageways, i get 60mpg indicated on the on board computer.
Have seen an indicated 64mpg on trips. but the journey does entail good hills and busy traffis.
Have had that on a long run to london 260 miles, ave speed 74 with mpg 64
That for me is more than enough and no grumjbles from me, have had a sporty car where tax due to emissions was mental and low MPG meant I sold it after 6 months.
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Slightly tangential, but does anyone check the CO2 emission figures used to calculate VED? I'm guessing that they are idealised and virtually impossible to achieve in practice.
The 'green' aspect of it doesn't bother me at all (I think CO2 is much more likely an effect of warming* than a cause) but it seems a little odd that that a whole raft of taxation is predicated on a measurement that is never checked or updated...
*from outgassing of the oceans. Don't get me started!
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I think CO2 is much more likely an effect of warming than a cause.
Why? Because some oil company has funded something that lets you go on believing a cosy falsehood?
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No - because the Vostok ice cores say so. Their data were famously part of Al Gore's presentations (also in 'An Inconvenient Truth'), plotted alongside global temperatures over the same 400,000 year period.
The two series appeared to be in close step, and were taken as proof by Gore and others that CO2 caused the warming. The thought that the warmth raised the CO2 level didn't get mentioned, and because of the compressed (400k year) time-scale on the graph, the 800-year CO2 lag wasn't apparent.
There is far more CO2 in the oceans than the atmosphere, and warming them releases the gas, as you will also notice if you leave your beer undrunk for too long on a hot day.
I'm simplifying, of course, but it seems a more rational explanation to me than the 'trapping' of heat by a gas that forms less than 0.04% of the atmosphere, especially when the actual data point the other way.
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>> Slightly tangential, but does anyone check the CO2 emission figures used to calculate VED?
It's not really tangential - indeed at one time they didn't measure MPG at all, it was calculated from the emissions figures.
MPG is measured now, but it very closely follows the CO2 figure.
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"MPG is measured now, but it very closely follows the CO2 figure."
So why is there just one CO2 figure, and why is considered valid for the life of the car? If HMG is really bothered about CO2, you'd think they'd want it checked from time to time...
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BMW 3-Series E90 - F30 320d ED - Nope, combined mpg is not achievable - rtj70
