Fuel Economy

[andyc1988]

Using Fuelly to do brim-to-brim fills is the best method of assessing fuel economy.

Fuelly calculates the true mpg based on odometer readings and litres filled. The obc tends to overestimate the efficiency compared to the true brim-to-brim results, but by less than 5%.

[bobmoo79]

We all like to think we're all getting the most out of our fuel, but honestly, if you want good economy don't buy a BMW!
If we were driving Peugeot's we'd all be getting 60+mpg without even trying, but then we wouldn't have the blue and white badge on the bonnet.

[Jamie214]

Would be interested to know the MPG of someone with a M140 that lives in London.

In fact, maybe I shouldn't know......

[DrewMsport]

My mpg seems to be going down? I do the same drive everyday for work, 94 mile roundtrip, and i was getting 60mpg to start and about 580 fill to fill on the trip computer as i reset every time i fill up. Which with personal mileage ment aswell as work trip one tank was doing me 7 days amd have been happily in a routine of filling up every friday on way home from an early finish. This tank however ive managed 460miles, but it has been steadily dropping the past few weeks down to 550, 520, 500 etc but this 460 seems rather bad. I could get 400-420 out of my civic type r fn2, 2.0l petrol. Anyone have an explanation for this? I thought as engines bed in they were supposed to get better? I now have 22k on and my best mpg results were at 15k. I certainly hope this hasnt settled into its lifetime range now.

[john1945]

My mpg seems to be going down? I do the same drive everyday for work, 94 mile roundtrip, and i was getting 60mpg to start and about 580 fill to fill on the trip computer as i reset every time i fill up. Which with personal mileage ment aswell as work trip one tank was doing me 7 days amd have been happily in a routine of filling up every friday on way home from an early finish. This tank however ive managed 460miles, but it has been steadily dropping the past few weeks down to 550, 520, 500 etc but this 460 seems rather bad. I could get 400-420 out of my civic type r fn2, 2.0l petrol. Anyone have an explanation for this? I thought as engines bed in they were supposed to get better? I now have 22k on and my best mpg results were at 15k. I certainly hope this hasnt settled into its lifetime range now.

Are you driving faster than you used to?. The air resistance of a car is proportional to the square of the speed. Double the speed and air resistance increases by a factor of 4. At about 55 mph air resistance is about equal to all the other frictional drags on the car (tyres, engine etc). Above that speed air resistance increases rapidly and fuel consumption will decrease just as rapidly.

[DrewMsport]

My mpg seems to be going down? I do the same drive everyday for work, 94 mile roundtrip, and i was getting 60mpg to start and about 580 fill to fill on the trip computer as i reset every time i fill up. Which with personal mileage ment aswell as work trip one tank was doing me 7 days amd have been happily in a routine of filling up every friday on way home from an early finish. This tank however ive managed 460miles, but it has been steadily dropping the past few weeks down to 550, 520, 500 etc but this 460 seems rather bad. I could get 400-420 out of my civic type r fn2, 2.0l petrol. Anyone have an explanation for this? I thought as engines bed in they were supposed to get better? I now have 22k on and my best mpg results were at 15k. I certainly hope this hasnt settled into its lifetime range now.

Are you driving faster than you used to?. The air resistance of a car is proportional to the square of the speed. Double the speed and air resistance increases by a factor of 4. At about 55 mph air resistance is about equal to all the other frictional drags on the car (tyres, engine etc). Above that speed air resistance increases rapidly and fuel consumption will decrease just as rapidly.

I dont think so, normally have cruise control set on motorway at about 72ish which is 2k rpm in 6th. (i like the revs sat on the 2k for some reason same as temp set to 22 degree on both sides.) and rest of drive is same 55-60 A roads and bit of 30mph through village zones where i always do 30, so speed has stayed the same. there was a section on bypass that had average speed cameras set at 50mph which has now gone, but surely 5 miles a day of doing 70 instead of 50 through there isnt dropping me 100 miles a tank???

[ste111]

My mpg seems to be going down? I do the same drive everyday for work, 94 mile roundtrip, and i was getting 60mpg to start and about 580 fill to fill on the trip computer as i reset every time i fill up. Which with personal mileage ment aswell as work trip one tank was doing me 7 days amd have been happily in a routine of filling up every friday on way home from an early finish. This tank however ive managed 460miles, but it has been steadily dropping the past few weeks down to 550, 520, 500 etc but this 460 seems rather bad. I could get 400-420 out of my civic type r fn2, 2.0l petrol. Anyone have an explanation for this? I thought as engines bed in they were supposed to get better? I now have 22k on and my best mpg results were at 15k. I certainly hope this hasnt settled into its lifetime range now.

I appreciate it wouldn't account for this much of a difference especially as you're doing long journeys but the cold weather can noticeably reduce you miles per tank due to extended warm up times (and possibly the increased power output in really cold conditions). In the old tdi i think it probably wasn't far off about a loss of 5mpg so around 10% and that was on longer journeys in summer v winter

[Jimi.K.]

I upgraded from a 1.0l Hyundai i10 4 months ago and in my 2016 218i (1.5l) I'm consistently getting 5mpg below what I was getting in the i10, which isn't too bad really considering the BMW has half the 0-60 time and more than double the torque and horse power.

99% of the time I just leave it in comfort mode and I'm currently averaging about 35mpg in rush hour city driving (compared to 40mpg in the i10) and 45-50mpg on a motorway run (compared to 50-55mpg in the i10).

[OneTwenty]

My mpg seems to be going down? I do the same drive everyday for work, 94 mile roundtrip, and i was getting 60mpg to start and about 580 fill to fill on the trip computer as i reset every time i fill up. Which with personal mileage ment aswell as work trip one tank was doing me 7 days amd have been happily in a routine of filling up every friday on way home from an early finish. This tank however ive managed 460miles, but it has been steadily dropping the past few weeks down to 550, 520, 500 etc but this 460 seems rather bad. I could get 400-420 out of my civic type r fn2, 2.0l petrol. Anyone have an explanation for this? I thought as engines bed in they were supposed to get better? I now have 22k on and my best mpg results were at 15k. I certainly hope this hasnt settled into its lifetime range now.

I appreciate it wouldn't account for this much of a difference especially as you're doing long journeys but the cold weather can noticeably reduce you miles per tank due to extended warm up times (and possibly the increased power output in really cold conditions). In the old tdi i think it probably wasn't far off about a loss of 5mpg so around 10% and that was on longer journeys in summer v winter

+1, the cold weather has a huge impact on MPG.

Engine takes longer to warm up, tyres take longer to warm up and the fact the air is colder means the engine should be producing more power - colder air = more power.

All these factors will hit your MPG in winter, but also improve performance!!

My old 120d used to drop from averaging 37-40mpg in summer to about 32mpg in winter.

My M240 is currently doing about 16mpg around town, 33mpg on a run.

[rs990]

When I had my 320d a few years back, I always noticed a significant change to my fuel economy when we switched from summer diesel to winter diesel at around this time of year.

[andyc1988]

My first quarter tank in the m235 since the cold hit and I'm averaging 24mpg! Hopefully this rises before the tank is empty, I can't live with a tank average of 24mpg when I haven't been "pressing on".

[moulin12]

I also have a 125i and unfortunately the fuel economy isn't as good as the brochures say. When I was looking for mine, the combined mpg figures shown in a BMW brochure were 42.8mpg.

I am a very light footed, smooth driver and my average is showing just above 34mpg.

I haven't done much long distance motorway driving yet, but from the little I have done, it seems to creep up towards the high 30s/early 40s in eco mode.

I too thought a newer more fuel efficient engine would have been better on fuel economy, but I wouldn't have bought the 125i if I was looking for pure fuel economy I suppose.

Sent from my SM-N9005 using Tapatalk

Is this the f20 125i? I was getting 40 mpg on mways in comfort mode, without even thinking about it and whilst enjoying the car.... , so suspect it could do better. Around town it was around 30, worse case 28.

Always used v-power or momentum.

My m240i, by comparison, is simply shocking - as low as 22 and around 24 on anything other m/ways (though still being run in).

[DrewMsport]

Are bmw engines known for the significant decrease in fuel economy in the cold? Ive been driving 15 yrs and havnt noticed such a variation in other cars. As someone stated they lost 8mpg just because of the temp? Very strange. Luckily i do long drives sonthe engine spends more time at temp.

[OneTwenty]

My old Focus ST did the same, one winter I had it down to 11mpg on my short commute!

[andyc1988]

My old Focus ST did the same, one winter I had it down to 11mpg on my short commute!

Similar to be, but I'd rather get 24mpg and commute 12 miles than get 35mpg and commute 36 miles .