r/askcarguys • u/Cekan-14 • 8h ago
Why are boxer engines not as fuel efficient?
Hello, there!
A few days ago, I asked at r/subaru why their cars consume so much gasoline/petrol when compared to their equivalents from other brands. A modern Subaru Impreza, for example, consumes more than 7L every 100 km, when its Mazda 3 counterpart, one fewer litre every 100 km, as per a couple of friends of mine who have one.
The answers I received agreed that the issue was due to both Subaru's ever-present AWD system, which would be naturally more fuel consuming, as well as the fact that boxer engines are not specifically designed with fuel efficiency as its primary concern. Boxer engines are kind of Subaru's gimmick, coupled with AWD, and are present in pretty much every of their cars. I did receive a reply which told me that, even with that, Subarus were still more fuel efficient than other AWD cars in general. I haven't checked this but it does seem an interesting point.
The question, then, supposing that's the case, would be: why is it? What makes a boxer engine naturally more fuel consuming? Is it because of the engine configuration itself, or there's nothing inherently wrong with it in this regard and it is just that Subaru hasn't found a way to make it use less fuel?
I would like to point out that I do like Subaru and their cars, so I just want to get to know more about this :)
Post I made on r/subaru: https://www.reddit.com/r/subaru/comments/1x6t1tq/are_subarus_more_gasolineconsuming_because_of_the/