Fuel Economy Update for August - Best Tank Yet Still Falls Short of Highway Rating - 2015 BMW M235i

Edmunds.com

Fuel Economy Update for August - Best Tank Yet Still Falls Short of Highway Rating - 2015 BMW M235i Convertible Long-Term Road Test

We tally the August fuel efficiency of our 2015 BMW M235i, which gets a slight lift with its best single-tank performance of the long-term test so far.

Read the full story here

darthbimmer

With my older 135i convertible I routinely get right around 24mpg (give or take 0.5 mpg) combined. I think the best single tank was only 25.5. That was all highway driving and nothing in excess of 75mph.

thepuff

I don't know what these drivers are doing...I average an easy 25.5 in stop and go traffic over a 44 roundtrip commute and more than 30 on any highway trip. That is with another passenger too.

csubowtie

A coworker just got a M235i (European delivery, lucky man). He was saying that while cruising switching between sport, normal, and eco modes made significant differences in mpg (as displayed by the car). I normally assume the difference in modes only affects things like suspension, shift patterns, steering effort, and throttle sensitivity, but not the parameters an engine runs at during steady state cruising. Perhaps Edmunds could investigate this. Does eco pull the boost and lean out while sport mode keeps the turbos spooled and the engine running richer in anticipation of fun?

jkavanagh

The difference among the modes (in terms of powertrain behavior) is throttle sensitivity and transmission calibration, and nothing more. 'Sport' mode holds gears longer and is more eager to downshift when the throttle is dipped. 'Eco' is stingier about using the a/c compressor too. If I recall, the M235i's sport mode holds the same gear on a highway cruise as the other modes, so there will be no difference in fuel economy during a cruise.