29.4mpg

[300hp]

I understand the skeptism and its warranted. Agreed my analysis is based on the OBC, only because I am lazy to go calculate otherwise. To be honest, the OBC read 29.7mpg at the time I exited the highway, 29.4 was what it read when I got to the mall after hitting traffic. My fuel gauge was just under half when I reset the OBC shortly after putting it in 8th gear, it moved a few ticks, maybe 2 if I remember well from there when I arrived.

Unfortunately I have no long drives planned until the summer when I plan to drive to Toronto or Montreal. This weekend I have a 100 mile round trip, will see how it works.

Trust me, I am as suprised as you are and would appreciate if others could experiment with this as well.

[motordavid]

300 hp: an anecdotal reading, from any car 'mpg' data, is just that...an anecdotal slice.

I often show 34-34 mpg on my VetteVert, after fillup/reset of mpg, from sliding away from the pump, back onto the highway at sane speed, for a qtr - half the tank.
(It 'cruises' in 6th at <1500 rpms).

That readout showed almost 32 mpg after 9,000 miles of our 13,000 mile Road Trip last summer...nice to see and take a pic of, but I was doing the arith on every tank, keeping records. That Vette averaged ~28 mpg for the entire 13,000 miles, so I am very confident in that mpg 'average'.

Our '01 X shows 20.6 on our OBC, but that reading has only been reset a few times in almost 11 yrs and 80k miles...but, it is a good indicator of what mostly highway trips can return, over a long time. In the real world, our X's per tank mpg varies from 17 low to 23 high...I have a small notebook full of tank fills/arith on it.

So, I am not skeptical, per se. It simply is not a real world mpg 'reading' based on a trip, or even a full tank consumption result. Could a gas E70 get '29' on a tank? Doubtful...though maybe a road trip at 50ish, in cooler weather, no A/C, tires pumped, and no uphill or loads, might get a tank in the mid-high 20s.

Not disparaging, just not realistic to expect '29' anytime, other than a short term 'readout' from any car brand mpg 'reading.'
GL, mD

[300hp]

My speed was between 60-70 mph on the said trip with AC on. This is only one observation and I started this thread to see what others will observe using the same method. At this stage I think its a wait and see game, like any experiment, it will take time to gather the data and prove or disprove that this was just an outlier observation. As said before, I did a SC trip and the truck only managed about 22mpg using the same method. So for the OBC to show 29.7 is a significant improvement. Lets see what others report but its worthwhile for the X35i owners to try this.

[JCL]

Just another data point for comparison. 535i, fuel consumption regularly measured over multiple tanks. I could consistently get 35+ mpg (Imperial) on the highway. 36 Imperial is 30 to the US gallon. That is with the twin turbo 3.0, so should be similar to the new 3.0tt. Here is what is not similar: 535i has less rolling resistance due to no awd; less frontal area and lower drag coefficient so less total aero drag; 1200 or so pounds less to lug around, and a six speed manual transmission driven for fuel consumption. All those variables improve the mileage over a heavier awd E70 with an automatic. Put another way, I don't believe the 29.4 mpg is actual, with all those variables piled on.

[300hp]

Here is the problem with your analysis though, F30 335i gets better fuel mileage than the E90, whether automatic or manual, similar weight. Thats another positive for the N55 (for manual) and N55 + 2 gears (automatic).

Agreed on "less rolling resistance due to no awd; less frontal area and lower drag coefficient so less total aero drag; 1200 or so pounds less to lug around"

Lets get the experiment going and lets see what data points we collect over the next month. I hope others join in and "no trolling allowed".

What parameters should we set so there is no cheating

[JCL]

First parameter to agree is to use real-world figures, as measured from fill to fill, not OBC figures and certainly not the artificial figures published by manufacturers, obtained from testing on a dyno and then 'adjusted' significantly to approximate real-world results. Right.

That is one reason not to trust the comparison of the two 335 models.

[300hp]

Originally Posted by JCL

First parameter to agree is to use real-world figures, as measured from fill to fill, not OBC figures and certainly not the artificial figures published by manufacturers, obtained from testing on a dyno and then 'adjusted' significantly to approximate real-world results. Right.

That is one reason not to trust the comparison of the two 335 models.

The guys over at bimmerfest are already reporting better mileage for the F30, there is no denying the F30 35i gets better mileage than the E90, its fact whether from the EPA or from real world results.

Hopefully others will post tank to tank, I can only post OBC at least until my Canada trip and this can be discounted by whatever % one deems fit.

[300hp]

The pic above is as of today, 2 days after said trip and those two days were in stop and go traffic, its at 22.4mpg (subject to discounting of course)

[RickM5X3]

Mileage wars with $60k+ SUVs. Liking it. It is not about saving gas though, its those inconvenient stops at the pump (so goes the story).

[300hp]

I don't think its a war, but if I expected everyone to sit down and accept that the 5000lb truck can do 29mpg h/way, then I would need to have my head examined. I was expecting the push back and its warranted. At the same time, you are right, its a 60k+ truck so +/-300/mnth at the pump is no big deal. I just want to know how much I can squeeze from this. A friend of mine has a 328i (E90), and I like rubbing it in his face once in a while