30+ mpg highway

[bobkap]

Been trying to break 30 fror some time now and finally did it yesterday on a 180 Mi r/t via GSP to the Jersey shore. ~600lb total load, cruise set at 65, 2 EZ pass low speed tolls each way. Been getting up to 29 same conditions using 89 octane but this time, 91. Actual was 30.3.
Weather: clear, low 50's light winds.
Mine is a near "plain jane" 08 X3 6M.
If BMW had chosen a .65-.70 ratio instead of .85 for 6th, 30+mpg highway would be commonplace even at speeds over 65. Mine tachs 2500 @ 65mph in 6th; 2000 or a little less would make a significant difference in highway mpg.
bobkap

[noego]

i'm with you on your comments on the gearing of 6th. down shifting to 5th or even 4th should not be a problem if quicker response to acceleration is the objective. cruising at 2500 rpm in 6th seems inefficient to me.

30 mpg! way to go.

[cngzsn]

I think the wind help you.

[bobkap]

cn,
Possible but not probable since the slight winds were E-W, not N-S, which were my directions of travel.
bobkap

[lilskel]

I haven't gotten my '08 yet (July), but having two X3's since 2005 getting 18-20mpg makes this hard to believe. I'm not using 91, but that doesn't make that big of a difference. Is the new engine that much better or is it just because it's 6sp?

[OCNYBMW]

Same here, I have 54K on my X3 and I have never got over 27-28. I usually average 21 or so on the highway. I do drive a bit fast, maybe average 75-80MPH over 50 miles or so.

Are you sure you did not turn the car off going down hills? :)

[x3ronnie]

Are these numbers based on the trip computer or actual calculations? The trip computer will display a slightly higher number, based on my experience. Also when you say the cruise was set at 65mph, again the speedo will show about 1 1/2 mph higher than actual road speed. I'm sure that the relatively flat terrain helped. That's great that were able to get such a high mpg, good for you!

[Mystic1]

We've never gotten anywhere near that. I think the best we've seen was 25. The new engine must make a huge difference in efficiency. BTW, we have a 2005 3.0i.

[MJS]

We've never gotten anywhere near that. I think the best we've seen was 25. The new engine must make a huge difference in efficiency. BTW, we have a 2005 3.0i.

It doesn't. I think the best I've seen on the highway is around 24-25. Unless I'm poking it along at 65 or drafting a semi, it ain't getting much better.

[trueX5]

I'm averaging 16.6 mpg. All city, since the highways are under construction so you can count that as city. :D

[bobkap]

Are these numbers based on the trip computer or actual calculations? The trip computer will display a slightly higher number, based on my experience. Also when you say the cruise was set at 65mph, again the speedo will show about 1 1/2 mph higher than actual road speed. I'm sure that the relatively flat terrain helped. That's great that were able to get such a high mpg, good for you!
ronnie,
All numbers based on computer. BTW, my odometer agrees exactly with mile posts and speedo so I don't think accuracy is a factor. Even if it was, this is a relative measurement with all factors except time being equal. The primary factor may be mileage; mine just turned 6K

[bobkap]

Same here, I have 54K on my X3 and I have never got over 27-28. I usually average 21 or so on the highway. I do drive a bit fast, maybe average 75-80MPH over 50 miles or so.

Are you sure you did not turn the car off going down hills? :)
OC,
Didn't turn off but I remember reading somewhere that removing your foot from the accelerator when descending a steep hill actually shuts off gas. Can anyone confirm this??
bobkap

[x3ronnie]

I can confirm that the auto trans downshifts to slow the vehicle down, with cruise on while descending a steep hill. Not sure if the fuel shuts off, but seems unlikely to me. I actually disengage the cruise to prevent this annoying downshift.