Setting Records on its First Road Trip, Part 2 - 2015 BMW M235i Convertible Long-Term Road Test

Edmunds.com

Setting Records on its First Road Trip, Part 2 - 2015 BMW M235i Convertible Long-Term Road Test

We finally made it to Zion National Park in our 2015 BMW M235i convertible. After taking photos for an hour and a half, it was time to head back to Vegas and then home.

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ebeaudoin

That is quite something that the car actually calculated on the low end of the MPG spectrum. That rarely seems to happen.

longtimelurker

Just think how much higher the average mpg would be on this car if it was actually taken on some road trips during its stay at Edmunds.

The Acura TLX was driven all over hell's half-acre while you had it - at least a half-dozen long trips...now are we going to think that its calculated average and the BMW's average mpg are somehow comparable?

cameronr

ebeaudoin said:

That is quite something that the car actually calculated on the low end of the MPG spectrum. That rarely seems to happen.

That the calculator underestimated actual fuel economy makes it, or at least its performance on this trip, something of an outlier. You're correct in noting that most of these systems tend to be a bit optimistic when it comes to estimated vs actual economy.

bankerdanny

I've never understood why the car computed numbers are off. The computer knows mileage driven and the exact number and length of each fuel injector pulse. One would think the computed economy would be extremely accurate.

darthbimmer

It's interesting that you get better fuel economy with your 235 convertible than I get with my older 135 convertible. Even on long highway trips I top out at about 25.5 mpg. That's what the trip computer reports, anyway. I'll compute it the old fashioned way for a few tanks to see how it comes out.

roadburner

ebeaudoin said:

That is quite something that the car actually calculated on the low end of the MPG spectrum. That rarely seems to happen.

My 2014 M235i's estimated fuel consumption is always 1%-2% below my manual calculation. In contrast, fuel consumption estimated by my wife's X3 is always 3% optimistic- at least. Then there's my son's 3er; its estimated economy is almost always a perfect match to the calculated number,

Back to the 2er, its lifetime fuel economy -since I've owned it- continues to average around 24.5 mpg.

longtimelurker

roadburner said:

ebeaudoin said:

That is quite something that the car actually calculated on the low end of the MPG spectrum. That rarely seems to happen.

My 2014 M235i's estimated fuel consumption is always 1%-2% below my manual calculation. In contrast, fuel consumption estimated by my wife's X3 is always 3% optimistic- at least. Then there's my son's 3er; its estimated economy is almost always a perfect match to the calculated number,

Back to the 2er, its lifetime fuel economy -since I've owned it- continues to average around 24.5 mpg.

Exactly - and the Edmunds LT 2er is sitting at 20.9 mpg after more than 15,000 miles, because it's "used for commuting."