Boxer Engine

The Boxer Engine (also called the flat engine) is a very unique piece of engineering. It is one of the most innovative things to exist in the history of the automobile, from its design, balance, and characteristics. It is often overlooked by many manufacturers because of the fact that it is usually more expensive to produce, but it has many unappreciated benefits. The only two manufactures in the world today that make significant use of the boxermotor are Subaru and Porsche, as well as motorcycle makers. While Subaru makes a flat four for their more affordable production cars, Porsche makes use of the flat six engine in their sports cars.

How a boxer engine works

In a boxer engine, the pistons move horizontally (left to right) instead of vertically, which gives them the name boxer because the pistons going out look like a boxer throwing punches. This setup has a very low center of gravity because instead of the block being tall, it is short and wide which allows for low mounting that conserves space. The flat configuration is also in perfect primary balance due to the horizontal movement of the pistons going opposite directions. The horizontal movement cancels out the negative vibrations from the other pistons. They are frequently used in motorcycles because the balance and low center of gravity makes handling characteristics better. In cars body roll while cornering is reduced with a flat engine which improves handling characteristics. Also, in a frontal collision involving a front engine boxer powered car, occupant safety is improved because instead of the engine going in towards the occupants (like with a V or Inline engine), the low center of gravity causes the engine to break away from the car which protects the occupants from impact. 

The flat engine was patented by Karl Benz, a German engineer that invented what is considered to be the first car: The Benz Patent Motorwagen. He made it in 1896, and it was very advanced for its time. BMW, another German automaker, developed their first motorcycles using flat engines. Ferdinand Porsche designed the Volkswagen Beetle to use a four cylinder air-cooled boxermotor, and it is the most produced car in the world. The Volkswagen boxer engine powered the Beetle, the Microbus (a more utility designed van), and the Karmann Ghia (which was designed to be a practical sports car, sporty body with cheap reliable Volkswagen engine). Porsche made air cooled boxer powered sports cars, like the 911 (which was influenced by the Volkswagen Bug) which all used an air-cooled flat six cylinder engine until 1996 when they developed a liquid cooled one which all Porsche's use today. And Subaru has been making all of their vehicles exclusively using boxer engines of both four and six cylinder design since the 1950s.

Air cooling is more practical and efficient for boxer engines. However, boxers today are water cooled (cooled with liquid, antifreeze/coolant).

The Subaru Impreza is powered by a 4 cylinder boxer engine, and it handles well because of the low center of gravity offered by a flat boxer engine. Also, even though it is a four cylinder engine (which are slightly unbalanced), it being a flat engine causes it to still be in perfect primary balance The Volkswagen Microbus used a flat-four and interior space was saved by using the low mounted boxer engine. This allowed Volkswagen to make the most possible space inside it usable, even though it was actually a rather small vehicle The Porsche 911 is inspired heavily by the Volkswagen Beetle, from its appearance to its usage of Rear Engine, Rear Wheel Drive. And its flat engine gives it efficient and space-saving power while being in perfect primary balance, making the engine run very smooth at all speeds.

ALL IMAGES ARE FOR DEMONSTRATION AND ARE NOT MINE