BMW’s latest Eco Concept is a mystery for everyone. The first rumors surrounding this new sports concept started spreading last year and ever since then, several contradictory reports have surfaced. From the Z9/Z10 to a Z2 even Z6 or simply, Vision Z Concept, the new car has stirred up in a lot of BMW fans.

Just a few weeks ago, the internet “erupted” when so-called of a slightly covered BMW Concept model were revealed. Speculations began, renderings started to flow, but BMW quickly shuttered everyone’s dreams: the spied car was simply a five-year old design study.

Well, to add some more fuel on the fire, quoting unnamed sources, uto Express UK brings up a new story rumor: the four-dour coupe concept to launch at Frankfurt will be powered by a three-cylinder turbo engine and a hybrid drivetrain.

Auto Express refers to the design of this concept as being a mix of classic BMW design cues and a modern, aggressive coupe shape, and the future upturn front-grille that will debut in other models as well.

The name for this concept? Well, we heard Vision Z Concept….still….but AutoExpress refers to it as the EfficientDynamics Vision, a more pompous name. The concept will return to the “shark nose” approach and MIGHT give a first glimpse  of the new 2011 6 Series.

We weren’t unable to confirm the story ourselves and we’re still sticking by the Vision Z name, but what we do know for sure is that three-cylinder engines are currently in development, units inspired from the Motorrad engines. In the past we also learned that a future BMW concept will feature a new transmission that is developed based on the technology from BMW’s motorrad division.

In about three weeks, we will be able to FINALLY separate the rumors from the truth and it will be interesting to compare the notes from various sources and past stories. But as usual, we do expect some leaked information prior to the show, so stay tuned for your daily BMW pill.

[Rendering and news by Auto Express ]