[Donny_1962]

Reminds me of a good run last year from Scotland.
4.10hrs over 284 miles, mpg 34.7 at an Av of 70mph.

That av did include some “faster” sections, overall av after 17650 miles is 27.2mpg.

Great engine indeed.

[Nobby Clark]

Lets see some full tank averages.
Let's face it, anyone can get great mpg on a short, ~50-60mph run.

[Abzynthe]

I'm not with my car right now, but this shows an average of 27.3 ish mpg.

I do quite often see the trip computer in the 13s though.

[JNW1]

Originally Posted by Nobby Clark

Lets see some full tank averages.
Let's face it, anyone can get great mpg on a short, ~50-60mph run.

To be honest even full tank figures don't necessarily tell the whole story as you don't always get it full to the brim every time. Moreover, those full tank figures will also vary significantly depending on things like the ambient temperature and the journey(s) undertaken and therefore I'd argue a cumulative average gives the most realistic view of what a car's achieving because over time and mileage it eliminates the effect of those sort of things.

Obviously you can look at individual tank figures as well (I do as I have both) but if someone asks me what mpg my car returns it's the cumulative average I quote because overall that's what it does in mixed driving.

Personally I give little or no credence to photos of a trip computer showing some fantastic mpg figure for an individual journey. As you say, not likely to be representative in the long-term and if the computer on my car's anything to go by quite possibly not even accurate for the individual journey either!

[chris-c]

ta da

[JNW1]

Originally Posted by chris-c

ta da

With the exception of the tankful at around 40mpg those are more the sort of figures I'd expect to see from an M3/M4! How and where are you driving to get mid to high teens from a 340i?!!

[chris-c]

Originally Posted by JNW1

With the exception of the tankful at around 40mpg those are more the sort of figures I'd expect to see from an M3/M4! How and where are you driving to get mid to high teens from a 340i?!!

How - fast + aggressively.
Where - short journeys.

[Eimal]

Originally Posted by JNW1

With the exception of the tankful at around 40mpg those are more the sort of figures I'd expect to see from an M3/M4! How and where are you driving to get mid to high teens from a 340i?!!

He's driving it like it should be, not sitting on the inside lane looking at the trip computer to see how he can increase his mpg

[Nobby Clark]

Originally Posted by chris-c

ta da

There we go. Far more representative.

My OBC reads around 1.5mog high for a full tank. Does anyone know how to adjust this?

Additionally, is the average MPG calculated over the miles since last reset or a shorter rolling distance?

[chris-c]

Originally Posted by Nobby Clark

There we go. Far more representative.

My OBC reads around 1.5mog high for a full tank. Does anyone know how to adjust this?

Additionally, is the average MPG calculated over the miles since last reset or a shorter rolling distance?

Since last reset. It's also not related to the trip computer either.

[JNW1]

Originally Posted by Nobby Clark

There we go. Far more representative.

Representative of what?

[JNW1]

Originally Posted by Eimal

He's driving it like it should be, not sitting on the inside lane looking at the trip computer to see how he can increase his mpg

It's perfectly possible to make decent progress in a 6-pot petrol and return decent mpg at the same time; however, I agree you're unlikely to achieve that with fast and aggressive driving on short runs.

To be honest I doubt a 35d would be very economical in that scenario either - only difference is you'd probably never have the inclination to drive one that way!

[chris-c]

Originally Posted by JNW1

Representative of what?

Of a prick driving around

[Nobby Clark]

Originally Posted by chris-c

Since last reset. It's also not related to the trip computer either.

Obviously

Originally Posted by JNW1

Representative of what?

Of a regular driving pattern over the life of the car.
As I said, anyone can knock out an impressive figure over a short range, even an tank or two but maintain that over 1000's of miles.
Even the poster who had the 70mph average - representative of his usual driving? Don't think so. Computer reset at 70mph, tail wind on the motorway - yup I can believe it.

[DaveH28]

For me the thing with the 3/440i is it can be as fast as you ever need to go while getting the sound and feel of a 6 cyl petrol engine... but then it compleltly affordable to run, I can't see there be much difference running cost to any 2.0l tbh..
I average 30.7, that over 6 months now or something... engine run in...
my journeys dictate how I drive, sometime cruise along, sometimes drive it like it should be....

[goodbyalfa]

My first full tank was driven like miss daisy (still breaking in) and I averaged 38.8mpg for the whole tank. Very impressed that if needed, it's perfectly economical to run. Tank 2 is sat at ~35 mpg so far with slightly more push from the engine, however I'm edging ever closer to the "let the throttle loose mode" (currently ~750 mile in...) at 1200 miles where who knows what that tank mpg will look like, but who cares right...

[JD6]

Originally Posted by chris-c

I do a couple of days driving it slowly and gently then I think "why the hell am I driving a 350+ bhp car like it is a 50bhp micra"

Exactly this.

Anyone claiming over 40mpg from a x40i should be sent on a special Speed Awareness Course to learn how to use the accelerator

[DaveH28]

Originally Posted by JD6

Exactly this.

Anyone claiming over 40mpg from a x40i should be sent on a special Speed Awareness Course to learn how to use the accelerator

Haha...
I get you..

I struggle to get less than 42mpg on my way home from work.. m61 and then m60.. but when I do get in after marvelling at the magnificence of possibly frugality of the b58... i give myself one lash for every single mpg I get over 30

[JNW1]

Originally Posted by JD6

Anyone claiming over 40mpg from a x40i should be sent on a special Speed Awareness Course to learn how to use the accelerator

Agreed and I don't think anyone's claiming seriously that as a long-term average you'd get 40mpg plus from a 40i (and if there are owners genuinely achieving that I'd suggest the car's wasted on them!).

However, using the performance as and where safe to do so - and going with the flow the rest of time - you'd see over 30 as an average quite easily IMO. From experience the older tech N55 35i would manage that without a problem and I can't see why a B58 40i wouldn't be at least as good (probably better).

[JNW1]

Originally Posted by Nobby Clark

Of a regular driving pattern over the life of the car.
As I said, anyone can knock out an impressive figure over a short range, even an tank or two but maintain that over 1000's of miles.
Even the poster who had the 70mph average - representative of his usual driving? Don't think so. Computer reset at 70mph, tail wind on the motorway - yup I can believe it.

Representative of Chris-c perhaps but I suspect those figures are not representative of the 340i population generally. He must be driving like he stole it to be getting less than 20mpg on a regular basis; obviously his fuel (and driving licence!) but I doubt most F31 340i's are - to use Eimal's view of the world -driven quite so "properly"!

[chris-c]

My normal commute does not really warrant a car like this but I bought it because I wanted it. Lots of people would not have a car for this sort of journey / use.

Most mornings take around 20mins to get into the office - 8.4miles broken down like this:
30mph speed limit for 0.7 miles - A long wait at a at the end junction here whilst the car isn't warmed up.
40mph speed limit for 0.7 miles - heavy foot onto this bit of road to catch a break in traffic. Three sets of traffic lights.
60mph speed limit for 0.8 miles - usually free flowing. couple of roundabouts
50mph speed limit for 1.5 miles - first 3/4 clear, last 1/4 normally a crawl. Car is usally warmed up by this point.
40mph speed limit for 0.5 miles - sometimes clear other times caught at traffic lights. Two sets of traffic lights.
70mph speed limit for 3.4 miles - Usually clear and a chance to stretch my legs.
20mph speed limit for 0.8 miles - clear but slow due to being on the work business park.

Reverse and the journey takes 15-20mins as it's usually a fair bit clearer.

So not a steady journey, lots of different speeds and lots of traffic lights. If I take a absolutely clear run it's about 32mpg. If it's a lot of stop starts its more like 26mpg.

If I go the long way to work its closer to 12 miles with the vast majority of it on the motroway / dual carriageway. I can usually do this route somewhere between 36-38mpg (best run was 39.5)

I'm quite anal when it comes to cost and I keep track of lots of journeys / fuel cost and over the time I've owned the car I've averaged 23.7mpg.

I even looked at the cost difference of driving the 8.4miles at poor economy VS 12miles at decent economy. The variable I couldnt work out was the bad days on the motorway when there is a jam or something so I took the worst economy for the short journey (26mpg) vs the average for the longer journeys (37mpg) . The difference is £1.89 for the short journey vs £1.90 for the longer journey. If the short journey is more free flowing I can get it to £1.54 for the journey.

When you look at the numbers like that you suddenly realise that it really doesn't matter and its far more fun to give it some welly. Also the couple of really poor fuel ups were just booting it EVERYWHERE local showing off the MPPSK and being a big kid.

I've also checked fuel rate whilst the car is warming up vs when it is warming up and I'm certain that the first half of my journey on a warm day is running ~20-25% lower MPG than when it has warmed up.

I've got a couple of longer journeys coming up in the next couple of weeks that will skew the results further. If you look at most owners they'll probably be doing far far higher mileage than me. I've had the car for 17 weeks and done 2165 miles. That's 127 miles a week or around 6600miles a year.

Compare that to another user on fuely who has owned the car since new (141 weeks) and they've done close to 290 miles a week on average.

Also... I do drive like an absolute prick sometimes. I like to make use of the power and love the cracks and bangs too much.

[MashinBenzin]

Mine is 21 months old and I've covered 9619 miles on fuelly. 32 fill ups averaging 28.0 mpg, best tankful of 38.0 and worst of 22.1.

6 mile each way urban commute with lights and roundabouts, I do easily see over 40 on a longish motorway run.