Ever since the S55 engine came out a very interesting debate started between BMW owners online: is the S55 really better than the N55 engine? Of course, that sort of conversation and this type of discussions have been going around for ages in BMW communities for a simple reason: the Bavarian car maker likes to be efficient. By that I mean all M engines are actually highly upgraded versions of mills found on ‘regular’ models.

The fact that the S55 was built atop the popular N55 mill was no surprise to those who have been following BMW. And yet, the S55 is a true performance mill that can be upgraded to vastly higher levels than the N55 and we have the video below to prove it. Shot by the guys from H2 Motors in Germany, the clip shows an S55 mill brought it for a crank hub issue.

The team proceeds to taking it apart and, coincidence or not, they also have an N55 around the shop so that they can show us exactly what’s different on the two. From the fact that the intercooler is positioned and cooled differently, to the number of turbochargers used on the two engines, there’s plenty to talk about here. The biggest difference though is how everything is cooled, the S55 mill having a closed-deck block while the N55 has an open-deck design. That means the block of the S55 can take more abuse and still run efficiently.

The guys do a great job at explaining not only the differences between the two but also what’s wrong with the S55 they have to fix. They go into detail about what needs to be changed and, if you have enough time, you can actually see a second video that shows how everything was put back together.