TEST DRIVE: BMW X5 M50d Final Edition – Saying Goodbye

Back in 2016 when the Dieselgate scandal surfaced, it was hard to guess just how big of an impact it would have on the industry as a whole. Personally, I think that was the tipping point for the beginning of the electric cars revolution. But apart from making electrified cars a lot more popular in a very short period of time, the Dieselgate scandal also turned a very powerful spotlight onto the compression-ignition mills that certain customers loved and couldn’t part ways with.

The DieselGate Changed The Industry Forever

The legislators around the world started an inquiry into how diesels were regulated and scrutinized everything related to them, no matter what brand they wore on their shiny plastic engine covers. Plenty of accusations flew left and right, and even today certain car makers are still being judged for various charges, accused of all sorts of wrongdoings.

In such a turbulent market, car makers decided to hit the brake pedal and start dropping diesels slowly but surely. As a result, the biggest issue was the sudden increase of fleet CO2 emissions once diesels were no longer a big part of their portfolios. That’s how we find ourselves at the end of 2020 with a considerably growing portfolio of mild-hybrid BMW models, and a steadily decreasing amount of diesels available, prompting yet more headaches for the people in charge.

The reason why cutting diesels from the line-up is problematic has a lot to do with fleet CO2 figures. American customers might not be aware of this, as diesels never really became mainstream in the U.S., but Europeans are very much aware of the fact that up until a few years back, diesels were the customers’ main choice. More than half of all cars sold here by BMW were powered by diesels, which have considerably lower CO2 emissions than their petrol counterparts.

After 2016 and the Dieselgate scandal, the sides switched, petrol models becoming more and more popular, in turn prompting an increase in fleet CO2 figures. Chip in the tightening regulations related to diesel engines altogether and the fumes they are allowed to emit, and you can figure how BMW and other companies are now feeling like they are caught between a rock and a hard place.

It’s a shame too, because diesels do have certain advantages and with modern-day exhaust treatments, they are far from the polluting, harmful powerplants they used to be. They are still unmatched in terms of efficiency, especially on longer routes and provide incredible torque figures.

Sure, they also have some disadvantages, like the trademark NVH levels way above what a petrol-powered car would have to deal with, but if we’re talking about straight six mills, that’s not really a problem anymore, thanks to the inherent balance these engines usually have.

One Of The Best BMW Engines – B57S

And that’s exactly what we’re going to discuss here today, the retiring of probably the best diesel engine ever made by BMW, the B57S.

That codename might not say a lot to many people but what you should know is that this used to be the only diesel engine in the world with a quad-turbo setup. Also, it was one of only two powerplants to share this architecture. Care to guess which one was the other engine? The W16 8-liter monster installed in the Bugatti Veyron initially and now the Chiron.

The problem is, no matter how nice this might sound on paper, it’s never a good thing to complicate engines and having four turbos fitted to one does cause a lot of issues. I’m not necessarily talking about the long-term reliability but rather the entire production process. That’s actually one of the reasons BMW invoked when they announced they will be ceasing the production of the quad-turbo diesel monster found under the M50d moniker.

The other was that the emissions levels required from new mills past January 1^st, 2021. Sure, BMW could’ve invested in making it cleaner but that process would be tedious and would require a lot of money, which would be better invested in electric and plug-in hybrid cars at this moment. That said, in September, the last B57S engine rolled off the assembly line. With it, a part of diesel history parted ways with us. But what was it that made this engine so special in the first place?

As I’ve always mentioned, certain cars feel better with a diesel engine under the hood. This category includes big SUVs, like the BMW X5 or the BMW X7. Recently, I had the chance of sampling a BMW X7 with the M50d engine under the hood and I think that would be my choice if I was looking to buy one. It has plenty of power, more torque than the 4.4-liter V8 from the M50i model and it allows you to cover copious distances without breaking the bank. It’s the same with the X5, if not even better, as the X5 is a bit smaller than the X7.

I was fortunate enough to try out the X5 in M50d guise a number of times and I walked away impressed every time. I know not many of you are fans of diesels but you need to understand this is a different breed altogether.

A Proper Send Off

That’s also why BMW decided to launch this Final Edition package for it, to mark the occasion somehow. This is a special package unveiled for select markets in Central and Eastern Europe, available solely on the M50d models of the X5 and X7 range. Only 220 BMW X5 Final Edition models will ever be made and they come with specific features.

The equipment package includes BMW Laserlight headlmaps, BMW Professional Driving Assistant, Integral Steering, Comfort Access, Display Key, double-glazed side windows, Comfort Seats, Crafted Clarity inserts in the cockpit, Head-up Display, BMW Parking Assistant Plus, Gesture Control, Wireless charging for your phone and the Harman Kardon sound system. A generous package then, which can be complemented with other various add-ons and a variety of color combinations. In our case, the press car had a black on black theme going which I absolutely loved.

The exterior was dressed up in Sapphire Black Metallic and, unlike regular M Performance cars, all the trims were also done in black. That included the usual Cerium Grey kidney grilles, air intakes on the front bumper, side mirror covers and tailpipes. The wheels were also sporting a dark theme and this whole dark theme worked perfectly with the Tartufo interior all dressed up in Merino leather.

But how can you tell this is a special edition model if you can order all those features separately? Well, the Final Edition versions, be it the X5 or the X7, come with a special dashboard trim, confirming in black and white that you’re sitting inside one of the 220 units scheduled for production.

Leaving this special inscription behind, what can you expect from a BMW X5 M50d? Seamless acceleration, tons of torque and probably the sportiest experience a diesel BMW SUV can offer.

An Incredible And Fun Drive

The throttle response is extremely sharp for a diesel, but then again, that was the whole point of the tri-turbo and then quad-turbo setup the M50d models got. I mentioned the former because this is how it all started, by ruffling some feathers when BMW unveiled its tri-turbo diesel M550d model back in 2012. Back then, M Performance models were still a novelty for many people and having a diesel one on offer was considered offensive.

That engine, the N57S had two small turbos, one for each three cylinders of the 3-liter straight-six mill, and a bigger one to which they were connected. Therefore, we were dealing with a parallel turbo setup for the two small ones that transformed into a sequential setup. Why all this complicated design? To make sure throttle response was as sharp as possible. The smaller turbos would spool up faster at lower revs, while the big one would take over at higher RPM. It was a setup that worked but in 2016, BMW came up with the new version, the B57S.

In this case, the four turbos had a parallel configuration and a sequential one at the same time. Each small turbo got a bigger one attached to it for an even more complicated design. Care to guess why BMW engineers went for this setup? For even better response, of course. In the process, they reached 400 HP and 760 Nm of torque, numbers that are simply unbelievable for a 3-liter mill.

However, as complicated as it may all sound, all of this work paid off. Driving an M50d X5 is an experience that could very well be used as means to convert petrolheads to ‘dieselheads’, if you will. Anyone dismissing diesel engines should drive this piece of amazing engineering at least once and I can guarantee you they will change their minds. The beating heart under the hood is smooth, refined, and shows more force in an instant than you would expect.

Other than that, the BMW X5 M50d Final Edition is a refined recipe. The current generation is the best ever made and that reflects in the sales figures. Unlike the previous F15 model, that used a revised platform based on the E70 model, the G05 finds its roots in the CLAR architecture and that comes with certain advantages. It has a refined ride, thanks to the air suspension, better room inside, a more premium interior and better looks all around.

Since this is the fourth generation X5, you’d expect that from a reputable German car maker and it’s clear to see why this SUV is a best seller. That’s also true for the M50d model, which was sold in more numbers than anyone anticipated so it will be hard to say goodbye.

Costly, But Arguably Worth It

The BMW X5 M50d without the Final Edition kit on it starts at 93,000 Euros in Germany and that’s a hefty amount of change. Being an M Performance model and coming with that brilliant engine under the hood does explain some of the cost. It also comes rather well equipped as standard, but if you add the Final Edition package to it you arrive at over 110,000 Euros and our tester pushed it even further, carrying a 127,162 Euro price tag.

That’s is not an easy price to digest and the bigger issue is that for that money, you can get the real M model – the BMW X5 M – and have some change left over. And no matter how much I love the M50d X5, I can’t honestly say I’d pick it over the BMW X5 M or the X5 M Competition.

Where does that leave us? At a tipping point. Albeit I’ll be sad to see this jewel of an engine go and with it the BMW X5 M50d model altogether, I think this is the perfect time for it to happen, as we now have the BMW X5 xDrive45e on offer, which will take over from now on. It has almost the same amount of power (394 PS) and a straight six under the hood that uses petrol instead of diesel. It has instant torque and a refined ride, being the perfect surrogate for those who will be missing the M50d, all the while releasing zero emissions driving it around town, as long as you use it as a PHEV and not a conventional SUV.

This outcome makes me optimistic about the future of our dearly beloved cars and the way we are accustomed to using them. Maybe the future is not so bad after all!