This roadster was the first BMW to appear with two large, horizontally mounted air intakes. The BMW 507’s creator Albrecht Graf von Goertz expressed his creativity via the design of the double kidney with various design projects. But the large-format air intakes were more than just for show as they served a practical purpose; they were in fact instrumental in providing fresh air to the radiator of the roaring V8 engine under the bonnet.

A new era for BMW came when the “new class” mid-range models were introduced. Here, the kidney grilles of the BWM 1500 were narrower than previous models, and it was set between two horizontal grilles that spanned the whole car. The primary and secondary air grilles would go on to inspire the front-end design of the core BMW models until the 1980s. This includes legendary vehicles such as the BMW 3.0 CS, BMW CSi and BMW CSL.

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The 1978 BMW M1 is notable as it was the first-ever official M-badged independent model. But the M1 was also special because of the design of its double kidney grille that incorporates ultra-flat air inlets. This iteration was used again in later BMW niche models, such as the BMW Z1 (1988) and the BMW 8 Series (1989).  

In the 1990s, the third-generation BMW 3 Series made another evolutionary leap when it went with a flat and horizontally mounted double kidney design. The two halves of the radiator ensemble looked very different from the first generation of the BMW 3 Series. They had a rectangular shape with slightly rounded corners and the kidneys were separated from the headlamp bands not by grilles by the surface of the car’s body. This design would later inspire many BMW models during this decade. This includes the BMW 7 Series (1994) and the BMW 5 Series (1995), through to the BMW Z3 (1995) and the following-generation BMW 3 Series (1998), and finally to the first two generations of the BMW X5 (1999).

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In 2013, BMW debuted the i3, the automaker's first mass-produced zero emission vehicle. This model started as a concept that was introduced back in 2011.

The front design of the i3 exemplifies one of the few occasions where the aesthetics of the kidney grille were dramatically changed. Not only was the i3's double kidney flat and relatively wide, but they are deliberately closed (because electric cars do not require air intake to cool the engine) and featured blue accents that allude to its electric nature. The aerodynamics of the BMW i3 on the other hand, was actually improved thanks to the closed kidney grilles. The design of the i3 would serve as inspiration for all future fully electric models by BMW.

BMW’s iconic double kidney design gained a new and relatively angular frame shape in two high-performance vehicles, the 8 Series and Z4. Most notably, the grilles form horizontally mounted, wide pentagons. The difference between the cars is that the grilles are connected on the 8 Series but unconnected on the Z4. 

Nevertheless, every newer BMW coupé hereafter shows off its sporty side with the kidneys 'opening downwards', thus providing a lower centre of gravity visually. The kidney grilles actually serve as secondary air intakes with an active flap/ control system that closes when required to reduce air resistance. 

The modern design of the double kidney truly stands out in the current BMW 3 Series. This version is defined by its connected kidneys, directly connected headlamp surfaces, pentagonal frame shape. The kidneys are also positioned higher than the upper edge of the headlamps, extending up to into the bonnet above a bend. Also, the upper edges of the headlamp are connected to each other by the edge of the kidneys.

A notable feature of the M Performance variants of the BMW 3 Series is the replacement of the classic vertical kidney rods with small wedge shapes woven into the mesh structure. Like prior models, the BMW 3 Series’ double kidney inspired the design found on BMW X7 and the current BMW 7 Series. That being said, those two models are much larger and appear to be even more striking.

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The new BMW 4 Series Coupé is steeped in tradition and is counted among the brand’s legendary sports cars. The focus this time around was on the individual design features, which include the large, upright, and forward-leaning BMW kidneys in the front. According to designer Seungmo Lim, who is responsible for the design language of the BMW 4 Series Coupé, the design of the vertical double kidney is a bridge to the future.

These two vision cars offer us a glimpse at what BMW’s primary distinguishing feature might look like in future models. The purely electric BMW Vision iNEXT, the double kidney turns out to be an evolution of the BMW i3 kidneys. It features a closed surface and houses sophisticated cameras, sensors, and other technologies for assisted and automated driving.

Meanwhile, the BMW Vision M NEXT, is a hybrid sports car with a sculpturally strong double kidney enclosed within glass emerges, with surfaces featuring engraved, stylised BMW logos. The kidneys incorporate a spectacular colour gradient that projects a mesmerising three-dimensional effect.

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