I was just wondering if anyone has came to the conclusion that driving their M3 between 70-85 mph resulted in more mpg then say running 50-65mph. I have a 07 M3 sedan S touring 2.3l with the 5speed auto/man tranny. No mods, purely stock. I live in central Tx. and am a easy driver. Local driving 45-65mph, 70% open road& 30% town results in an aveg of 24.5 to26.5mpg. On the last three out of town trips of 200 miles or more I drove with cruise on. Avg speed was like 70-85mph with the milage averging between 32-37mpg.
What would be causing my much lower milage on my local driving or is this normal. Thanks for any reply's.

 

to put it simple the higher speed u maintain (static speed) over long distance the better mpg u get ex. gain anywhere from .5 to a full 2 mpg in my 2.0 auto with basic bolt ons a exhaust leak and 6 codes when i drive on highway goin about 70-80. Now if your constantly playin with the gas pedal like goin from 40 to 65 back to 30 or anything like that your afr's are constantly changing either adding or subtracting fuel (among other things), if your at a static speed everything stays the same and w/o the arfs movin around fuel consumption stays the same. A better example, which is goin to make you more tired? running at a constant speed or slowing down speeding up and slowing down again, when u start to run faster after runnin slow u need to push harder to get back up to speed vs just running at the higher speed u dont feel as much stress cuz your keeping the same pace for so long. (hope i didnt confuse u im not that good at explaing things, just ranting and puttin motors together ^^)