Fuel economy - anyone beating the official figures?
Discussion
Ron99 said:
M1C said:
Agreed, SMWBO has a 107 and it would do more way more than 31mpg at 75, id estimate mid-40's maybe more.
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We have Vauxhall's equivalent as a shopping trolley, a Viva. .
It gives 50mpg on long 75mph runs and similar mpg when used for commuting in rush hour although my wife tends to always be too hot or too cold so the heated seats, heated steering wheel or aircon is always on which knocks 5mpg off when she uses it compared to when I use it.
It's most economical at 30-40mph and can give 70mpg on clear roads cruising at those speeds (country lanes, urban roads at night etc).
Official figures are U=50mpg, Ex-U=70mpg, C=61mpg.
With small cars (and to some extent cars with small engines) their mpg and acceleration tend to suffer a lot more than large cars if there are lots of electrics running or lots of people/luggage on board. The official mpg tests are conducted with just the driver, with no electrics running.
Pretty decent figures there though! And heated seats and steering wheel? How posh?!??!
But yeah. The 107 with just me in...it's just about acceptably nippy...with pregnant SWMBO and our boy in....big difference...so this will also have a bearing on mpg.
I think if i scooted along at 50mph in the 107 i could get some serious mpg...but i've never really got the chance to do that these days.
Official combined figure on my 320Cd is 49.6mpg and I've managed 50.5mpg (brim to brim) calc over the last 100k.
However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
emicen said:
Official combined figure on my 320Cd is 49.6mpg and I've managed 50.5mpg (brim to brim) calc over the last 100k.
However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
How do you begin to calculate the 12%??However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
M1C said:
I think if i scooted along at 50mph in the 107 i could get some serious mpg...but i've never really got the chance to do that these days.
I've experimented with our Viva; it gives better mpg at 30-40mph than 50-60mph. Somewhere around 25-30mph in 4th at 1500-1800rpm is where I'd guess it's at its most economical but I haven't studied it that closely.
Despite the upshift nag light being on when doing 4th/30mph, the small, three-cylinder, torque-light engine struggles to pull 5th at 1500rpm for 30mph unless it's a smooth, flat, straight road with no electrics/aircon putting a drag on the engine.
In fairness, being a town car, it's no bad thing that it should be most economical at 30mph.
Edited by Ron99 on Tuesday 11th July 15:43
Hoofy said:
emicen said:
Official combined figure on my 320Cd is 49.6mpg and I've managed 50.5mpg (brim to brim) calc over the last 100k.
However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
How do you begin to calculate the 12%??However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
Living very close to the middle of the M8, everywhere I go features motorway driving. Also find there is very little variety in my driving, by and large, I drive the same half dozen or so journies that account for most of my mileage.
So just broke them up in to urban and extra urban elements and a bit of excel later; 12.13% of the last 4000 miles have been urban, 87.87% ex-urban.
Average urban element of my journies 2.3 miles, average extra urban element 16.6 miles.
Now I just need to figure out what that means for which vehicle is best suited. Averaging 51 miles a day puts it outside pure electric range of most PHEVs seeing as I have no destination charging at any of the locations I regularly visit.
emicen said:
Hoofy said:
emicen said:
Official combined figure on my 320Cd is 49.6mpg and I've managed 50.5mpg (brim to brim) calc over the last 100k.
However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
How do you begin to calculate the 12%??However, mass tracking of fuel consumption doesn't end my geekery, I also know that my driving breakdown is 12% urban / 88% extra urban. So with that bias factored in, the official ex-urban 62.8mpg looks fairly unachievable.
Living very close to the middle of the M8, everywhere I go features motorway driving. Also find there is very little variety in my driving, by and large, I drive the same half dozen or so journies that account for most of my mileage.
So just broke them up in to urban and extra urban elements and a bit of excel later; 12.13% of the last 4000 miles have been urban, 87.87% ex-urban.
Average urban element of my journies 2.3 miles, average extra urban element 16.6 miles.
Now I just need to figure out what that means for which vehicle is best suited. Averaging 51 miles a day puts it outside pure electric range of most PHEVs seeing as I have no destination charging at any of the locations I regularly visit.
Not sure I should mention this as it's a bit sad in an M car but last summer I managed 30.7 mpg in my E39 M5 gently mooching, with family aboard, around North Wales. I thought that was pretty amazing as I usually get about 15 around Manchester.
Checking its extra urban it's meant to get 28mpg so a small increase on the official figures.
Checking its extra urban it's meant to get 28mpg so a small increase on the official figures.
Not sure exactly but in the the combined figure for my 640d coupe is around 51.3mpg.
Best I've had over a run is 59mpg (see pic) but mostly its low 50s on a long run. So I guess I'm pretty much on par according to the trip computer.
However, as someone stated previously in this thread, the computers are too optimistic, my brim to brim calculations suggest my actual mpg is 2-3mpg lower.
My 6 series has a coast mode in eco pro which disengages the gearbox, I'm unsure on whether this is better for mpg or not, there are occasions on the motorway where I can be sat at 75 down a hill and maintain that speed for a long time, whereas in gear coasting I'd need to accelerate to maintain. Equally in 30 sections the coast can enable you to sit at 30 for quite some distance if it's flat.
Best I've had over a run is 59mpg (see pic) but mostly its low 50s on a long run. So I guess I'm pretty much on par according to the trip computer.
However, as someone stated previously in this thread, the computers are too optimistic, my brim to brim calculations suggest my actual mpg is 2-3mpg lower.
My 6 series has a coast mode in eco pro which disengages the gearbox, I'm unsure on whether this is better for mpg or not, there are occasions on the motorway where I can be sat at 75 down a hill and maintain that speed for a long time, whereas in gear coasting I'd need to accelerate to maintain. Equally in 30 sections the coast can enable you to sit at 30 for quite some distance if it's flat.
I almost always hit the claimed average for my vehicles over high mileages of mixed driving; 43mpg in a Volvo C70 D5, and now 40.3 mpg in a 2019 MX5 against a claimed 40.9 WLTP (and it gets thrashed hard and also plenty of high motorway speed trips too, so I'm stunned at that).
Never had anything miss it by a mile, but then I've never had a car with a tiny engine and a big turbo claiming absurd figures.
Never had anything miss it by a mile, but then I've never had a car with a tiny engine and a big turbo claiming absurd figures.
OK, so I bought a facelift 320i E91 Touring a few weeks back as not sure what was happening business wise and wanted something cheap.
It has the n43 2 litre direct injection petrol engine and is manual.
The official urban figure is 34mpg, it is averaging nearly 39mpg nipping around.
On a run it will easily do 45mpg and if you sit at 70mph it will break 50mpg no problem at all, and over a long journey too.
Very, very impressive.
More so when you consider I used to have the same car with the N47 320d engine in it, that used to average around 39mpg nipping around too and on a run do 55mpg, so only a smidge more.
I also bought an F31 320d Efficient Dynamics touring on Friday, mainy as my daughter is back with us and seems to have taken over the 320i, this was local, and I was quite into the whole MPG thing.
I drove that back from the coast, only 20 miles or so, and on the Norfolk roads it was returning 70+ mpg, and even after booting it down the A47 and A11 it was still showing 65mpg by the time I was home.
Reset the MPG when I filled up and nipping around it is showing 57mpg average.
The official figure is 54mpg urban and extra urban is 78mpg. I reckon I could get close to 78mpg over 100 miles in this if I was really careful. Very impressive.
Plus, with 205.60.16 non runflat tyres it is so comfy.
It has the n43 2 litre direct injection petrol engine and is manual.
The official urban figure is 34mpg, it is averaging nearly 39mpg nipping around.
On a run it will easily do 45mpg and if you sit at 70mph it will break 50mpg no problem at all, and over a long journey too.
Very, very impressive.
More so when you consider I used to have the same car with the N47 320d engine in it, that used to average around 39mpg nipping around too and on a run do 55mpg, so only a smidge more.
I also bought an F31 320d Efficient Dynamics touring on Friday, mainy as my daughter is back with us and seems to have taken over the 320i, this was local, and I was quite into the whole MPG thing.
I drove that back from the coast, only 20 miles or so, and on the Norfolk roads it was returning 70+ mpg, and even after booting it down the A47 and A11 it was still showing 65mpg by the time I was home.
Reset the MPG when I filled up and nipping around it is showing 57mpg average.
The official figure is 54mpg urban and extra urban is 78mpg. I reckon I could get close to 78mpg over 100 miles in this if I was really careful. Very impressive.
Plus, with 205.60.16 non runflat tyres it is so comfy.
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