[letitbegood]

For anyone that may be able to comment,

I purchased a new 2015 xDrive28d last December. So far I have been consistently averaging approx. 22 MPG, well below the advertised MPG of 27 city/34 highway.

My driving mix has been approx. 75% city, often in stop and go traffic. I am not an aggressive driver, and drive in comfort mode (not sport). I have approx. 6k miles on the car.

Just wondering if anyone thinks this is still excessively low, even with the high city driving and traffic?

I took the car to service and told them the issue. They said they could not find anything wrong, but based on what other drivers are getting I cannot help but feel there is an issue with the car.

Any thoughts are appreciated. Thanks.

[ianfp]

Originally Posted by letitbegood

For anyone that may be able to comment,

I purchased a new 2015 xDrive28d last December. So far I have been consistently averaging approx. 22 MPG, well below the advertised MPG of 27 city/34 highway.

My driving mix has been approx. 75% city, often in stop and go traffic. I am not an aggressive driver, and drive in comfort mode (not sport). I have approx. 6k miles on the car.

Just wondering if anyone thinks this is still excessively low, even with the high city driving and traffic?

I took the car to service and told them the issue. They said they could not find anything wrong, but based on what other drivers are getting I cannot help but feel there is an issue with the car.

Any thoughts are appreciated. Thanks.

Hi, I have the N47 diesel, and without trying, I average 35MPG (UK) in heavy town traffic and 45 to 48MPG on a run fully loaded. This is using a combination of comfort, sport and sport+ modes.

I think you should be getting much better figures than you are!

Do you have the option of driving a demo at your dealer and re-setting the fuel clock before starting out? It may give you some idea as to what you can expect.

[Eaglesview]

Originally Posted by ianfp

Hi, I have the N47 diesel, and without trying, I average 35MPG (UK) in heavy town traffic and 45 to 48MPG on a run fully loaded. This is using a combination of comfort, sport and sport+ modes.

I think you should be getting much better figures than you are!

Do you have the option of driving a demo at your dealer and re-setting the fuel clock before starting out? It may give you some idea as to what you can expect.

I have 15,000 miles on my N47 and drive 75% rural and 25% urban in a mild manner. Consistently show 35+ mpUSgal. Open road long distance at 60 to 70 mph 38-39.

Dash econmy reading is usually 1+/- mpg optimistic compared to actual calculated economy.

[tuatua]

We have 27,000 miles on our 2015 28d. Our overall mpg is 33.0 with our daily driving being 50/50 city/highway with very little stop & go. We just finished a mostly interstate 2,000 road trip driving at 70 mph and mpg was 39.0. All this in comfort mode.

[temoore48]

In the 6,000 miles I have driven, I am averaging 30.8 mpg. I do about 50/50.
If you haven't tried it, Fuelly is a free service you can sign up for, and each time you fill up, you text Fuelly your Miles, Price per, Gallon Gallons, separated by spaces. Easy to remember as it is MPG (miles price gallons).
You can also see what other drivers are getting. There are 12 X3 diesels, and they range from 28 to 35 mpg.

[gIzzE]

How many miles is your stop/start city driving?

These diesels take around 10 miles or 15 minutes to get up to temperature, and until that point they will obviously be using a lot more fuel.

Is the car getting to temperature quickly? And staying there even with spirited driving?


How many miles have you done? Mine is now at 45k miles and is starting to feel much looser and getting better mpg all the time.

I would fill up to full, reset the obc and then do a full tankful and then fill up again and work out what you are getting. My 335i actually underead, it said 26.9mpg on the obc but was 29mpg calculated.

[Peter_R]

gizzE has hit the nail on the head.

Low engine temperatures and short trips is THE problem with diesels, those conditions completely ruin the diesel engine's efficiency.

To give you an idea, we do all our local shopping and short trips in my wife's little SEAT Ibiza 1.4 SC petrol car and it averages 37.1 mpg (UK)

In contrast, we only carry out long trips of at least 50 miles or more in our 2013 X3 xDrive30d M Sport (6 pot 3.0 litre diesel) and we have averaged 39.1 mpg (UK) over the last 8,500 miles. This is better than many achieve with the 2.0d N47 engine. I do not hang about and drive on the speed limit all the time. Sometimes a little faster on motorways.

[kevink1]

With my 2015, I'm averaging about 31mpg overall (US numbers). I'm driving more highway miles than what the EPA uses.

I get about 26 in town. But, my trip to work is about 9 miles, partially highway, so I don't have a lot of real short trips.

[Peter_R]

Originally Posted by kevink1

I get about 26 in town. But, my trip to work is about 9 miles, partially highway, so I don't have a lot of real short trips.

Many in the UK consider that distance to be a short trip and that the diesel engine is still not running efficiently. More so in the colder weather.

[kevink1]

Originally Posted by Peter_R

Many in the UK consider that distance to be a short trip and that the diesel engine is still not running efficiently. More so in the colder weather.

I'm not in a large city. I used to drive 4 miles to work in my previous car. During the 4 years I drove the longer distance in the car, the gas mileage creeped up. So it affected my gas engine too.

So I expect my mileage would have been lower in my X3 if I still worked at my old location.

[Peter_R]

Originally Posted by kevink1

I'm not in a large city. I used to drive 4 miles to work in my previous car. During the 4 years I drove the longer distance in the car, the gas mileage creeped up. So it affected my gas engine too.

So I expect my mileage would have been lower in my X3 if I still worked at my old location.

What was your previous car? If it was not the same as your current car and not a diesel then you cannot compare.

[letitbegood]

Thanks everyone for all of the feedback.

Interesting info on short drives/engine temperature. When in the city, some of my drives are pretty short (i.e. 3-7 miles). But others are longer. Will take note of the engine temperature and how long it takes to warm up, although I would think living in warm weather should help speed things up?

Something else that I didn't think about until after my initial post, and I have no idea if this is related, but maybe someone can answer the following:

On the day I was at the dealer to pick up my car, there so happened to be a fire in the dealership garage above the showroom from a car that caught on fire while it was being detailed. There was tons of smoke everywhere (the fire department was called) and my car so happened to be on the same level right in the midst of all the smoke, waiting to be detailed. It took several additional hours to pick up the car due to this. They checked it all out and said everything was fine, and I never noticed anything unusual in my car, but I am wondering if my car being in the middle of all of this smoke could be related to my poor MPG? I would think a sensor would go off if there was an issue with emissions or anything else, but I am not too knowledgeable in this area.

[letitbegood]

One other question for those of you that have posted the average MPG you are getting. Can you tell me what your average speed has been during this time?

Thanks again.

[Peter_R]

Originally Posted by letitbegood

but I am wondering if my car being in the middle of all of this smoke could be related to my poor MPG?

NO! You are overthinking this!

[kevink1]

Originally Posted by Peter_R

What was your previous car? If it was not the same as your current car and not a diesel then you cannot compare.

My previous car was a G35. But my gas mileage improved when changing from a 4 mile trip to work to a 9 mile trip to work. Same issue, takes a while for the engine to get to normal operating temperature.

[Peter_R]

Originally Posted by kevink1

My previous car was a G35. But my gas mileage improved when changing from a 4 mile trip to work to a 9 mile trip to work. Same issue, takes a while for the engine to get to normal operating temperature.

Unfortunately you cannot even contemplate comparing. It is like comparing apples to pears.

[kevink1]

Originally Posted by Peter_R

Unfortunately you cannot even contemplate comparing. It is like comparing apples to pears.

Explain it to me, as if I was a complete dummy.

Gas engines don't work as optimally when cold. So mileage is lower if you do a bunch of short trips. Is it different with diesel?

[Peter_R]

Originally Posted by kevink1

Explain it to me, as if I was a complete dummy.

Gas engines don't work as optimally when cold. So mileage is lower if you do a bunch of short trips. Is it different with diesel?

I am sorry, I am not going to spend hours explaining to you because all the information you require is on the internet for all to see.

Enjoy your search and reading, you will undoubtedly be a lot wiser at the end of it all.

Note 1. All UK F25 X3's are diesel engined. We do not have a petrol engined one.

Note 2. Gasoline engines are typically 30% efficient while diesel engines can convert over 45% of the fuel energy into mechanical energy. However the diesel engine takes longer to heat up, so it will not give the higher mileage per gallon until it is up to its optimum working temperature. Most likely the reason for your poor figures. Experienced drivers in the UK (around 50% + - a few % of UK cars are diesel) understand this and do not expect to get the better fuel consumption until they have travelled about 10 miles.

Note 3. I travelled around 220 miles yesterday and for the first 10 miles it showed less than 25 mpg after that it was in the mid 40s, leading to an overall average of 41.4. This is excellent for a heavy 6 pot 3 litre diesel 4 x 4.

[Andy_o]

Mpg is so hard to quantify so dependant on who what when and how

Ie: I live on top of a hill, my sons school is a mile away at the bottom of the hill

On the way to the school with a cold engine I get 60 mpg !

On the way back I get about 18 mpg !!

Overall it's about 27 mpg

On my commute from up in the hills down to almost sea level I get about 44mpg over 35 miles

Coming home .. Same route and speeds I get about 38 mpg .. Overall about 41 mpg there and back .. But coming back generally up hill where going to work is generally downhill

Point is .. It's all subjective

[Max Well]

Originally Posted by Andy_o

Mpg is so hard to quantify so dependant on who what when and how

Ie: I live on top of a hill, my sons school is a mile away at the bottom of the hill

On the way to the school with a cold engine I get 60 mpg !

On the way back I get about 18 mpg !!

Overall it's about 27 mpg ...

Very true, Andy, which is why discussing average mpg is, to coin Peter's phrase, "comparing apples to pears" - even when discussing the same model type and in similar situations such as 'city driving'. A host of variables come into play as you have aptly pointed out, so I continue to have difficulty seeing how comparisons are useful. Another case in point - as I always get my wife's older X3 when we purchase a new one, I am driving the exact car she did, but even around town following similar routes as she formerly did, I average 3 mpg more than she did. Subtle variations in hitting traffic lights, slowing and speeding with traffic flow, etc., all play a role in the final numbers.

I was truly hoping others would provide actual data on their model types so we could graph and use as a reference on the 'Horsepower and Speed - the graph' thread [ http://x3.xbimmers.com/forums/showthread.php?t=1004702 ]. If you look at the last entry's graph from 3 Aug 2014, that shows the mpg one should expect from a 35i variant at any speed on level ground (keeping in mind it only has an 'n=2').

And I can attest the graph remains spot on, so much so in fact, I can provide the following test question - I drove a 300 mile non-stop pure highway trip on Monday with cruise control set at 77 mph. Lots of elevation changes in-between, but end point same altitude. Looking at the graph, was my average mpg: a). 29 mpg b). 27 mpg c). 25 mpg d). 23 mpg ?

And a confession, I continue to hold out hope others will provide numbers on our other X3 engine types - I will be pleased to graph those and place in that thread for reference.

[kevink1]

At NO point did I claim that a diesel does not require time to warm up to get its best MPG.

So your claim is that since a gasoline engine is less efficient overall is that it doesn't require time to warm up to get its best fuel economy? That if I started driving a gasoline car for short 1 block trips I would get the same economy as if I drove it 5 mile trips? Or 10 mile trips?

That is essentially what you are claiming when you talk about having to drive longer distances in a diesel to get to optimal mileage numbers, but claiming my experience a gas engine where shorter trips got lower gas mileage than a little longer trips doesn't apply.