anyone use their economy gauge?
 

I have never used mine to drive, and decided to try to do it tonight starting with a full tank of gas. Man, to keep it in the black you gotta move slow! I am going see what kind of improvement I can see out of it. Anyone see improvement that is worth the reduced pace?

It lets me know that I'm getting vacuum if I'm having an issue, but that's about all its worth to me.

I dont use mine.

I watch it sometimes.....it does help prevent lead footing....and its interesting to watch it while at a light with the A/C on....you can see it move when the compressor engages and disengages.

Yeah. My sister was in the car tonight with me and she had to have the a/c on. She was complaining I was driving too slow. I told her that her beloved a/c was costing us precious black space on the gauge and that I'd have to go slower to make up for it.:P

It sure does! Red is almost unavoidable with the A/C on in city driving....especially at rush hour. :eek:

My BWM has it - and decent reference point to find that sweet spot in highway driving. It's sobering to see what toll aggressive driving takes on MPG. The W220 has the trip mpg calculation feature. I do a 21 mile 1 way commute to work city/highway about 50/50 and I will average 22 mpg with careful driving. Turn that trip around and race to every stop light, fast acceleration etc. and that trip goes to 17.

I actually refer to my vacuum gauge quite often. However, I figure I'm only getting about 5% to 10% better mpg than what the "normal" reported mpg for the 300CE is. Been averaging about 23-24 mpg per tank and (I think) most people quote they get somewhere around 20-22.

I've seen as high as 26.2mpg on a recent long trip (over 400 miles) of all highway with cruise control. In the M103 300E....

I look at mine all the time. I kind of make it a game to try and keep mine on the high side of 20.

Also, I read somewhere that it really isn't a vacuum gauge. On the W140 at least, it is supposed to be a comparator output of road speed vs injector pulse width.

On my BMW it is linked to the 'puter and is a real mpg gauge. Of course it is an instant gauge and not an average. It is tied to the road speed, RPM,and load and is not a vacuum gauge. When you come to a stop and are idling it goes to 0.
I use it to TRY to stay on the high side of the 20's

I use mine for a couple of things. When setting the cruise control on an open highway its useful for picking an efficient cruise speed. I think this is probably the main purpose especially on roads like the autobahn where you have to make decisions to cruise at 100mph or perhaps 130mph. Aircraft POH's have charts for deciding cruise speed vs engine fuel consumption. On a high speed long distance trip it could be the difference in stopping for gas and not stopping for gas. One of the 140's strong points is its incredible range.

Its also quite useful for determining if the road you are on has an upward slant or downward slant. If you notice the MPG dropping your going up an incline and the cruise is throttling up to compensate and if you all of a sudden have great fuel economy your likely on a slight downward incline.

On the later cars, it's definitely not a vacuum guage.

I always thought it was, but then when my cluster was out to have an issue fixed I looked and can confirm there is no vacuum line running to it. It's an actual computerized MPG guage, based on fuel consumption vs. speed. It must use one of the wheel speed sensors and a reading from the injection system to get the calculation. But it's definitely all electronic, no vacuum involved.

I pay attention it more frequently. I try to keep it in black zone. Hoping to get the idea that I am burning less gas and it is changing my driving habit. I have never test if it give more gas milage. May be just psychological effect.
My other cars do not have it so I don't care when I drive those.

I have always notice on mine (m103) that on the freeway it will always move more to the left (economy) side when I shift down to third. This never made sense to me but it's never bugged me enough to figure out why it's doing it.