While all gas-powered internal combustion engines work basically the same way, there are several different engine designs found in today's cars. It's most common to see engines using an inline or V-shaped layout for their cylinders, but a small number of cars have used boxer engines over the years.
In this article, we'll be talking all about the history of boxer engines, including where they first appeared and which cars they can still be found in today.
What Is A Boxer Engine?
You're probably already familiar with what a boxer engine is if you're reading this article, but on the off chance you're uninitiated, let's take a quick second to go over this particular engine design.
Boxer engines are flat engines, and the terms "boxer engine" and "flat engine" are often used interchangeably. However, it's not entirely accurate to do so; while all boxer engines are flat engines, not all flat engines are boxer engines.
A flat engine always has its pistons mounted horizontally on either side of the crankshaft. The difference between a boxer engine and other flat engines, however, is that the opposing pistons in a boxer engine have separate crankpins, which allows the opposing pistons to move inwards and outwards at the same time.
This is in contrast with other flat engines, where the opposing pistons share a crankpin. In these engines, as the piston on one side moves in, the other piston always moves out.
The First Car To Use a Boxer Engine
The boxer engine was actually one of the earliest engine designs to exist. It was invented all the way back in 1897 by Karl Benz, who you probably also know as being the inventor of the car itself.
This first boxer engine was dubbed the "kontra" (kontra being the German word for against) and came in two different versions; a 1.7-liter version that made 5 horsepower, and a 2.7-liter version that made 8. Both of these engines were two-cylinder units.
However, no one ended up using this design at the time. The Mercedes-Benz company made the decision to focus on developing inline engines for their cars, and Benz's design was forgotten about for a few decades.
In the 1930s, at the behest of Adolf Hitler, Ferdinand Porsche set about designing a new car that could serve as a true car of the people. Unlike the United States, which had had the Ford Model T for over 20 years before that point, Germany still didn't have a car that the average citizen could afford; at that time, only 1 in 50 Germans owned a car.
As you can probably guess, the car that Porsche ended up designing was none other than the iconic Volkswagen Beetle, which used a 995 cc boxer-four that made 25 horsepower. Initially, though, the Beetle was not actually called the Beetle; the original name was the "Kraft-durch-Freude-Wagen", which translates to the "Strength Through Joy Car".
Which Cars Used and Still Use Boxer Engines?
While the boxer engine isn't one of the most popular designs, plenty of cars over the years have used them. Every single original Volkswagen Beetle made from 1938 to 2003 used basically the same engine; while it was enlarged several times over the years and reworked to make more power, it still used the same basic boxer-four design.
The Porsche 911 is another car that has used a boxer engine for its entire life. Since its introduction in 1964, all 911s have used a boxer-six. Other Porsches that have used boxer engines include the 356, the 914, the 912, and the Cayman/Boxster.
Perhaps most famously, Subaru has used boxer engines in basically all of their cars since 1966. The first Subaru to use such an engine was the Subaru 1000, which used a 1.0-litre boxer-four that made about 54 horsepower.
Aside from being the first Subaru to use a boxer engine, the 1000 was also one of the first front-wheel-drive cars ever to be made in Japan, and one of the few Subarus to have front-wheel-drive (most Subarus since came with all-wheel-drive).
Other manufacturers that have used boxer engines at one point or another include Alfa Romeo, Citroën, and the now-defunct Tatra.
What Are the Advantages and Disadvantages of Boxer Engines?
As with pretty much any engine design, boxer engines have their own advantages and disadvantages compared to inline or V engines. If you're at all curious as to why boxer engines are used sometimes but not all the time, the advantages and disadvantages do a pretty good job of explaining it.
Firstly, because boxer engines are wide instead of tall, this lowers the center of gravity of the engine. If you want your car to handle well, it's always better to have a lower center of gravity, as this keeps the car planted more firmly on the road.
The design of a boxer engine helps make it more balanced, which has a positive effect on how the engine runs. Obviously, there are a lot of fast-moving parts and strong forces occurring inside an engine, but if everything is balanced well, the engine will run smoothly and not cause excessive vibrations.
Being able to position the engine very low inside the engine bay can also potentially make the car a lot safer in the event of a crash.
Now, for the disadvantages. While the flat design of a boxer engine lowers the center of gravity, it also makes these engines a lot wider than either inline or V-shaped engines. This can obviously make it more difficult to actually fit a boxer engine inside a car.
Because of how wide a boxer engine is and because the cylinder heads are located on the sides of the engine instead of the top, this means that some maintenance that would be pretty simple on an inline engine is a lot more complicated on a boxer engine. For example, changing spark plugs is considerably more difficult on many boxer engines.
Finally, there's the fact that boxer engines are just a bit more complicated and expensive to design than other engine types. It's for these reasons that generally you only see boxer engines appear in more performance-oriented cars.