2009 X5 35d MPG (graph)

[FunfDreisig]

With many of you taking delivery of a 2010 X5 35d in the coming days I thought you might like to see a graph of some real world 35d MPG since mid Aug 2009.

This graph is computed from a 'fuel log' where each time we fill up, we write down the date, mileage, gals and $. MPG is simply the miles driven since the last fill up divided by the gals. MPGLong is the miles driven since new divided by the total gals since new. The MPGLong calculated this way matches the mpg computed by the X5's Trip Computer. Note: I set the Trip Computer to zero at the time of delivery.

Using the Car Data mpg for short distances does not give you a very good feel for life time mpg. On a typical 10-50mi run the Car Data mpg will show an avg of 24-25 MPG. And we frequently see runs of 27-30 MPG. BUT our actual avg MPG from time of purchase is only a little more than 21.5 MPG. The 35d does not get very good mileage until it is warmed up. IOW the longer the run the better the mileage.

As you can see, the mpg (both per tank and since new) are getting better with each fill up This is at least in part because of the very poor mpg on the first tankful when we were letting the engine run to keep the AC working in 100+ degree temps while adjusting the various settings, etc for each driver. The one low mpg tankful included a couple of trips to the quarry, towing back 2+ tons of sand. When towing a couple of tons, the 35d mpg drops to 15-18mpg depending on terrain.

It would be nice to compare similar mpg data from other 2009 & 2010 X5s

Funf Dreisig

Edit: the MPG in this post is Miles per US Gallon

[XXX555]

Again, excellent post. I will keep a fuel log for comparison, hopefully within a couple of weeks.

How does your fuel log compare to the BMW onboard computer if your able to compare apples to apples?

[JCL]

Good information, very clearly presented, and far more valuable than the oft-quoted "my OBC shows XX mpg. An additional data point that would be valuable (over time) is to note the relative mileage during summer and winter, to see if winter fuel has any appreciable effect. You may not be a climatic zone cold enough for it to matter, but it would be interesting to see. You could also note that this is US mpg, for our non-US members.

Thanks for posting this.

[FunfDreisig]

Originally Posted by JCL

... An additional data point that would be valuable (over time) is to note the relative mileage during summer and winter, to see if winter fuel has any appreciable effect. You may not be a climatic zone cold enough for it to matter, but it would be interesting to see. ....

Thank you. You have a good point. Our fuel log includes the date and I store it in the spread sheet. So it will be easy to graph MPG vs Date in the future. My guess is that there will be a difference in MPG between Summer and Winter, even though I live in Central Texas where the I don't think they sell a different fuel for winter. We use the AC 100% in Summer and almost 0% in Winter

Funf Dreisig

[FunfDreisig]

Originally Posted by XXX555

....How does your fuel log compare to the BMW onboard computer if your able to compare apples to apples?

Thank you. The E70 X5 has two separate areas where it will calculate and store mpg data in the iDrive Car Data. They both store Avg Speed and Consumption (MPG). But differ on the other info.

1 - I use the "Onboard Info" to quickly check MPG over short runs e.g. 5-50 miles.

The Onboard Info never exactly matches the MPG per tankful because I haven't let it calculate MPG over a whole tank yet.

2- I use the "Trip Computer" to maintain MPG and other info since delivery.

The Trip Computer Consumption (MPG) has always been very close to the MPGLong calculation from my Fuel Log data. Note: It will never be exact since I zeroed out the Trip Computer at delivery and so it includes some MPG data from the very first tank put in by the dealer. In retrospect I wish I had zeroed the Trip Computer when I filled the tank the first time. That way I would have avoided the very low MPG due to sitting at idle making all the driver's settings etc.. The Trip Computer also tells me the total number of hours we've driven the X5. Just like our Kubota

FWIW I will be updating this thread with new graphs as I collect more data.

Funf Dreisig

p.s. And yes, as JCL points out, the graph is Miles per US Gallon

[FunfDreisig]

Originally Posted by XXX555

....I will keep a fuel log for comparison, hopefully within a couple of weeks....

That's great. The more info we can collect the more informed potential 35d owner's can be.

BTW you don't need to keep an old fashioned Fuel Log in a small 3x5 spiral notebook like we have on every vehicle we've ever owned. You can just write your current mileage on each gas receipt and keep them together until you have time to type them into a spreadsheet.

FWIW we keep track of other events in our "Fuel Log", like when we change tires, add oil, have a flat, take it in for service, etc.

Funf Dreisig

[XXX555]

My 335i looses consistently 1.5mph with the A/C blasting compared to no A/C.

[Craig]

My highest MPG in the city has been 21 MPG

Highway, highest 25 MPG @ 80 MPH. I average around 24 on the highway with the air cond. on @ 80 MPH.

With the air cond. off, and in warmer weather, I get better mileage. You're correct, it does get worse MPG when the engine is cold. It gets a lot better when it's warm and the longer you run the engine. I get 18-20 MPG in the city with the air cond. on when it's summer here in the Midwest.

Craig

[jaaX3]

This thread has inspired me. I will start logging upon delivery next week.

[FunfDreisig]

Uh-Oh we may have to request a special forum for X5 Diesel Deviants who brag about their MPG graphs instead of 0-60 times

Funf Dreisig