Arrange the cylinders at 180 degrees: this is the principle of flat engines, including boxers. Ideal for lowering the center of gravity, this architecture has won many followers, from the VW Beetle and Citroën 2CV to the Porsche 911 and certain Ferraris. Retrospective.
To lower the center of gravity of their models, manufacturers are now bragging to us about the merits of electric cars and their heavy batteries in the floor. But at the time of the all-powerful thermal, another solution pursued the same goal: the flat engine whose Carl Benz signed the first copy in 1896. Arranging the cylinders at 180 degrees makes it possible, in fact, to placing fairly heavy mechanical parts closer to the ground, to the benefit of road handling. For this, the engineers have exploited two different possibilities which are distinguished by the shape of their crankshaft. This has an impact on how the pistons move.
In a so-called “boxer” engine, their ballet can evoke boxers fighting in the ring: they move closer or further apart according to the rotations. The 180-degree V-engine is less common, more cumbersome and less often mentioned. In his case, when one piston is up, the other is down and vice versa. This is in particular the choice made by the Ferrari 512 BB, whose misleading name would be more synonymous with Brigitte Bardot than Berlinetta Boxer, contrary to what we have long thought.
Porsche faithful to the boxer since the 356
There is not the same kind of ambiguity about the Boxster, which takes its name from the contraction of “boxer” and “roadster”. Porsche is one of the oldest defenders of this type of engine, which he was already using on his first production model, the 356. The stainless 911 was going to for its part, in 1963, mark the passage from the four-cylinder to the six-cylinder boxer. She remains faithful to it nearly sixty years later.
The German brand will go so far as to design a flat twelve-cylinder to animate its terrifying 917, which will allow it to win the first of its many victories in the 24 Hours of Le Mans, in 1970. While we were even recently able to immortalize a prototype of 917 powered by a sixteen-cylinder flat atmospheric 6.5 of 800 hp. Intended for the American CanAm championship, the latter will unfortunately never have the chance to race, Porsche having finally opted for a lighter and more efficient flat 12 turbo.
A flat-twin that has become legendary for the 2CV
In France, even if Panhard had beaten him on the Dyna X, it is however to Citroën that the “flat” owes its hours of glory. The chevron brand had chosen a flat twin for its famous 2CV. Many French people still remember the atypical sound of this mechanical curiosity, which was also found in the Ami 6 and 8, Dyane, Méhari or Visa. The GS, for its part, opted for a four-cylinder flat, architecture also used by the GSA, Ami Super or by the unloved Axel. A feature that is only a distant memory today. After the takeover by Peugeot, the need to share components to reduce costs quickly brought Citroën back to the path of inline engines.
Subaru, Guardian of the Temple
The Japanese Subaru has made the boxer its trademark, to the point of equipping its entire range with it… with the exception of the new Solterra electric SUV and a few models unknown to our market. At home, the tradition goes back to his first family sedan, the 1000, released in Japan in 1966. To adapt to European demand, the Japanese brand did not hesitate to develop the first diesel boxer, launched in 2008. An initiative that will unfortunately not pay off. Today, the four-cylinder flat house therefore prefer to bet gradually on the hybrid. Subaru thus remains a very discreet player with us, while it is experiencing real commercial success across the Atlantic without ever having given up its mechanical particularity. In turn, thanks to a partnership, Toyota also inherited a four-cylinder flat in its range, first on the GT86 coupe, then on its replacement GR86, both twins of the Subaru BRZ.
A long-popular engine type
Going back much further in time, in the 1960s, we can already find traces of a sporty Toyota with a flat engine, the small Sports 800. This convertible coupé with a targa roof tried to compensate for the modest 49 hp of its twin-cylinder by its featherweight. But the mechanics of this rarity actually derives from that of a model with very different ambitions, the Publica, launched in 1961. A popular car project that ended in bitter failure, unlike one of its sources of his inspiration, the first Volkswagen Beetle, presented in 1938. Throughout his endless career, this German icon also used a boxer, equipped with four cylinders and installed in the rear. It is also from this base that Porsche started for its 356.
Icons of the hippies, the first VW Combis were also proponents of the flat-four, as was the Karmann-Ghia coupé. Alfa Romeo, from the Alfasud to the 145/146, and Lancia, with its Flavia and Gamma, also succumbed to the charms of the flat engine for some time. Not to mention Chevrolet, whose Corvair has however mainly made itself known for other reasons. She was indeed “victim” of a cabal of the famous American lawyer and politician Ralph Nader, who judged her ” dangerous at any speed with its boxer six-cylinders installed in the rear. It has thus become, in spite of itself, the symbol of the first attempts to combat road safety, relegating its mechanical singularity to the background.
