[FirstBMWLA]

I have an 07 335i Coupe. Recently I've noticed when viewing the instant mpg
on highway cruising in 6th at 60mph I get readings of 50mpg+ on flat roads. At 75-80 it seems more accurate reading ~35mpg but that still seems too optimistic. Just wondering if there is any SBs for this or anyone experience similar issues.

I have reset both the avg mpg and avg speed and it still reads way too highway in 6th at 60mph. I have a BT tool if it could possibly be used to
reset anything else.

[BTM]

It's a very rough estimate...not sure about the algorithm used for mileage calculation but it's definitely very optimistic...for example I just filled up my car and it says 480mi to empty tank...to date I haven't gotten more than 350mi out of a tank

It's also a little funny how it will read --.- when stopped, when technically your mpg is 0mpg

[bimmernoob]

I am assuming you are refering to the gauge on the tachometer (RPM).

I not an expert on this but i don't think the real time MPG meter has anything to do with the avg mpg and speed settings.

my experience with it is that it is really only directly related to the application of your throttle and how much power the car/engine needs to reach/maintain the car at the speed corresponding to the throttle. Your case about 50mpg+ going 60mph in 6th. It simply means your car is "cruising". The engine is not putting out much power to maintain the car at that speed. But the moment your car needs to output more power (say, the slope of the road increases ever so slightly), you should see the meter change. Similarly for the 75~80 scenario, the car will experience more wind resistance, and that's probably why you see the mpg go down.

With all that said, I think in real world driving condition you really should see that meter go up and down even if you maintain the car at constant speed.

[Oulixes]

Originally Posted by bimmernoob

I am assuming you are refering to the gauge on the tachometer (RPM).

I not an expert on this but i don't think the real time MPG meter has anything to do with the avg mpg and speed settings.
...

I agree that the numerical result of the MPG algorithm has little to do with the observed MPG. Note that the 330(x)i and the 328(x)i have a "hardware" MPG gauge at the bottom of the tachometer, which IMO is useless. In the same location, the 335i has a "hardware" oil temperature gauge - the MPG algorithm result can be called by programming the display panel.

[Flyer]

My '09 328i actually reads very accurately, and I regularly get 450-500 miles per tank.

[donsgolf2012]

Originally Posted by Flyer

My '09 328i actually reads very accurately, and I regularly get 450-500 miles per tank.

well, EFF off, i get around 18.8 MPG, not sure if the counter is correct but i always fill up around 270 miles b/c the low fuel warning is on

[Ron1n]

Originally Posted by BTM

It's a very rough estimate...not sure about the algorithm used for mileage calculation but it's definitely very optimistic...for example I just filled up my car and it says 480mi to empty tank...to date I haven't gotten more than 350mi out of a tank

It's also a little funny how it will read --.- when stopped, when technically your mpg is 0mpg

That # is based on your most recent average of gas usage (last 18 miles). That's why it's so high. You must have been on the highway behaving before you filled up.

[BTM]

Originally Posted by Ron1n

That # is based on your most recent average of gas usage (last 18 miles). That's why it's so high. You must have been on the highway behaving before you filled up.

Wow, exactly right! About 20miles of all highway...and I rarely drive on the highway. Otherwise it's a more humble 400miles...but still have yet to reach that mark...at least I know what the computer is thinking now

[bmw999]

Originally Posted by Flyer

My '09 328i actually reads very accurately, and I regularly get 450-500 miles per tank.

Do you drive exclusively highway?? I have same coupe '11 and I can get about 450 range from a tank with 80% highway driving. I've been trying to reach the mighty 500 but I end up driving 20% city and it kills it.