Actual MPG Vs listed MPG
Discussion
Hi all,
Ok so we just got a lovely Diesal Clio dci 1.5.
Listing says mpg 83-88mpg. Honest John says 60mpg. Well we just did our first 10 gallon tank and got 430 miles. 43.0mpg. that's the same as my petrol. Slightly dissapointing.
Does this sound right?
Thank you.
Ok so we just got a lovely Diesal Clio dci 1.5.
Listing says mpg 83-88mpg. Honest John says 60mpg. Well we just did our first 10 gallon tank and got 430 miles. 43.0mpg. that's the same as my petrol. Slightly dissapointing.
Does this sound right?
Thank you.
Edited by laskoir on Saturday 25th August 09:54
The "listing" is derived from a standardised test, done in a lab. Every single new car goes through the same procedure, so that the results are comparable between cars. It's illegal for manufacturers to give any figures other than those obtained through the official process...
2001-17 - http://www.dft.gov.uk/vca/fcb/the-fuel-consumption...
2017-on - http://www.dft.gov.uk/vca/fcb/wltp.asp
They might not be comparable with your own driving - maybe you drive in harsher conditions, maybe you're just a leadfoot. Maybe your measuring is wrong (especially if you're using the wrong litre-to-gallon conversion). Maybe, if it's a used car, it's a bit broken.
2001-17 - http://www.dft.gov.uk/vca/fcb/the-fuel-consumption...
2017-on - http://www.dft.gov.uk/vca/fcb/wltp.asp
They might not be comparable with your own driving - maybe you drive in harsher conditions, maybe you're just a leadfoot. Maybe your measuring is wrong (especially if you're using the wrong litre-to-gallon conversion). Maybe, if it's a used car, it's a bit broken.
You should easily be getting 60mpg with a mixture of driving so long as you drive sensibly, either there is a problem with the car or it's your driving style.
If you are anything like my wife then it'll be your driving style, yet she still moans about relative poor mog in her car, I've tried to tell her but she just won't listen!
If you are anything like my wife then it'll be your driving style, yet she still moans about relative poor mog in her car, I've tried to tell her but she just won't listen!
Sounds like that pizza I had last night, that didn't resemble the advertised pic either. That was a shocker I can tell you.
I wonder if the general public will ever wise up to the fact that there is FA difference between petrol and diesel these days, especially if you don't do monster mileage.
I wonder if the general public will ever wise up to the fact that there is FA difference between petrol and diesel these days, especially if you don't do monster mileage.
I'm running an elderly 406 coupe 2.2 hdi for the last few years.
Extra Urban is quoted at 58 mpg and at congested 50 mph M5 crawls up and down to Bristol I've been averaging 65-67 mpg.
The average figure is 44 mpg and on the 12 mile, hilly school run It averages 44 mpg throughout the year.
Extra Urban is quoted at 58 mpg and at congested 50 mph M5 crawls up and down to Bristol I've been averaging 65-67 mpg.
The average figure is 44 mpg and on the 12 mile, hilly school run It averages 44 mpg throughout the year.
stevieturbo said:
Car manufacturers get fined billions for following rules and creating cars that passed all the tests asked of them.
Yet when they tell blatant lies and bulls
t about mpg....nobody says a word.
They don't lie, the mpg quoted is the result of one of the tests asked of them.Yet when they tell blatant lies and bulls
t about mpg....nobody says a word.WonkeyDonkey said:
I find the older the car the more accurate the mpg figures are. Guess manufactures have got wise on how to game the test over the years.
You also need to understand that fuel economy is measured as a reciprocal, ie as miles PER gallon. This is important when we look at actual fuel quantities being consumed! ietake a 25mpg car, drive it for 100 miles and it uses 4 gallons of fuel.
take a 50mpg car, drive it for 100 miles and it uses 2 gallons of fuel
take a 100mpg car, drive it for 100 miles and it uses 1 gallon of fuel.
each time you double the economy, you half the consumption. so, drive a 25mpg car badly, and the economy only gets a bit worse in magnitude, but drive a 50mpg car badly, and the nominal loss of economy looks to be much greater.
for example, let say you use an extra 1 gallon of fuel by braking, driving faster, etc on our 100 mile journey, then:
our 25 mpg car actually does 20 mpg (5mpg loss)
our 50 mpg car actually does 33 mpg (17 mpg loss)
our 100 mpg car actually does 50 mpg (50 mpg loss)
So, cars that can do higher mpg are more likely to miss those figures by a large margin when driven poorly....
Max, your analysis above is badly flawed and completely illogical. There is no reason to expect that driving hard uses the same absolute extra amount of fuel such as the gallon in 100 miles in your example. It's far more likely to be a proportion of the normal mpg of the car such as an extra 10% or 20% and there is also no reason for that percentage to differ much from car to car other than for high powered vehicles there is more extra bhp you can use to soak the fuel up with.
WonkeyDonkey said:
I find the older the car the more accurate the mpg figures are. Guess manufactures have got wise on how to game the test over the years.
Yeah, but, no but....You have to remember that cars economy used to be measured when driven over as set speed/distance by an actual driver.
In current mileage testing it is done on a rolling road by a "robot" and that is why they used to be more accurate & more achievable, not because manufacturers didn't make it up then.
It comes down to how you drive it and keeping a consistent approach for 'best' mpg. Remember the 2000 fuel shortage? I was driving a short wheel base Daihatsu Fourtrak 2.8 non turbo, average mpg 38 driving 90 miles a day mixed town and motorway. With the crisis I had to creeparse along to save fuel, 48 mpg over just over a week.
Jeep XJ 2.5 diesels I have driven over last 5 years; 26 local and 30 on a long run.
Latest Jeep Renegade I have is a 4wd 2 litre diesel, 40.5 local driving ( 39.5 with air con on this past month) and 48 mpg average on a 1500 mile Dumfries and Galloway holiday.
When I was looking into buying a Renegade I read a post on a forum where a guy had just bought a small engine 2wd Renegade and said the mpg was half what was predicted. He also went on to say the tyres were s*ite as the front tyres wore out in a couple of thousand miles...says it all really doesn't it?
Jeep XJ 2.5 diesels I have driven over last 5 years; 26 local and 30 on a long run.
Latest Jeep Renegade I have is a 4wd 2 litre diesel, 40.5 local driving ( 39.5 with air con on this past month) and 48 mpg average on a 1500 mile Dumfries and Galloway holiday.
When I was looking into buying a Renegade I read a post on a forum where a guy had just bought a small engine 2wd Renegade and said the mpg was half what was predicted. He also went on to say the tyres were s*ite as the front tyres wore out in a couple of thousand miles...says it all really doesn't it?
Mr2Mike said:
WonkeyDonkey said:
I find the older the car the more accurate the mpg figures are. Guess manufactures have got wise on how to game the test over the years.
That must be it. The NEDC mandated testing scheme is just a rumour started by "big oil".I’ve only read the last few posts but as I understand it the current mpg test evaluations used to obtain a vehicle mpg are done on a dyno and derived from complicated gas analysis.
The website “Honest John” gives real world mpg figures submitted by drivers
I have never ever had a car that got close to the manufacturers figures
The website “Honest John” gives real world mpg figures submitted by drivers
I have never ever had a car that got close to the manufacturers figures
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