The 2017 BMW i3 with improved, larger battery option was first announced over four months ago.

And immediately we heard that the 2017 edition would arrive with a 33.2 kWh (94 Ah) option, good for 114 miles of range in the all-electric version - a 41% improvement over the earlier BEV version of the car.

As for the extended range, BMW i3 REx...nothing on the range or efficiency.

BMW i3 REx Gas Tank Location - Full 2.4 reservoir now available in 2017 33.2 kWh edition in US

BMW i3 REx Gas Tank Location - Full 2.4 reservoir now available in 2017 33.2 kWh edition in US

All we heard at the time was that the 2017 plug-in hybrid BMW would also receive the 33.2 kWh battery option, and now also use the full 2.4 gallon gas tank as in the European version .

Of note: The earlier 22 kWh (actually 21.6 kWh) version of the i3 REx in the US was electronically capped at 1.9 gallons in order to comply with CARB compliance regulations for BEVx status.

Even now, the EPA has yet to formally publish the range ratings for the i3 REx on their website.

Fortunately, the BMW i3 REx (like its BEV sister-car last week) has finally been released from port holding in the US, and we have an actual shot of the Monroney window (below) found on some just arrived, dealer inventory cars - thanks to InsideEVs contributor Warren M)

And the news is...well, its not that great.

The 2017 BMW i3 REx has an all-electric range of 97 miles, with the new, as promised, 2.4 gallon fuel tank enabling a further 83 miles of driving, for a total range of 180 miles - which translates to just 30 more net miles over the 2016 i3 REx.

The longer range, 2017 BMW i3 REx starts from $47,450 (+995 dst), $1,200 more than the 22 kWh/2016 edition.

Here is a comparison between the original 22 kWh BMW i3 REx and the newer 2017 edition:

2017 BMW i3 REx (33 kWh) vs 2016 BMW i3 REx (22 kWh)

2017 BMW i3 REx (33 kWh) vs 2016 BMW i3 REx (22 kWh)

2017 BMW i3 22 kWh/60 vs 2017 BMW Ah Versus i3 94 33.2 kWh/Ah: +34 more range

2017 BMW i3 22 kWh/60 vs 2017 BMW Ah Versus i3 94 33.2 kWh/Ah: +34 more range

Clearly we can see that the 54% larger battery translated to just a 34% increase in all electric range, and the new 26% larger fuel tank has translated to only 6% more range on petrol, while the extended range efficiency overall has dropped significantly.

Interesting, the same battery upgrade in the all-electric version added 4 more miles overall (34 miles total, moving from 81 miles to 114) than was added in the REx, despite the extended range BMW also adding that extra half gallon of petrol capacity.

Why the lower improvements in range, especially on the gas extender?  Perhaps the performance operation of the BMW i3, often criticized for being under-powered while driving on gas in the US (and sometimes leading to a lawsuit for its "Reduced Power Mode"), has been dialed up to better fit consumer demand.

2017 BMW i3 REx (33 kWh/94 Ah) Window Sticker (click to enlarge)

2017 BMW i3 REx (33 kWh/94 Ah) Window Sticker (click to enlarge)

Hat tip to Warren M!