The M550d xDrive requires you to readjust any thoughts of traditional performance car values

What is it?

Forget the sixth-generation M5 – the mighty BMW M550d xDrive is now the ultimate BMW 5-series model. At least it is in real world terms, on the sort of roads and in the changeable weather conditions we tend to encounter every day.

Spearheading a new range of so-called BMW M Performance models positioned and priced between the German car maker’s standard offerings and its more potent M division line-up , the rapid four-wheel drive diesel powered saloon establishes a lofty new standard of performance for oilburners: official figures put the M550d xDrive’s 0-62mph time at 4.7sec, standing kilometer (very much the new benchmark) at 23.7sec and a top speed at 155mph, even though it is clearly much higher without electronic regulation.

What's it like?

Granted, that’s not ultimately as fast as the new twin-turbocharged 4.4-litre V8 petrol engine powered M5 in a straight line, but it is the way it achieves these figures with such pervading potency at only moderate engine revs that makes the M550d xDrive so utterly appealing. It is a car that always feels like it has more in store, more to offer – even when scything along at triple digit speeds out on the fast lane of an unrestricted German autobahn. That, and the fact it is claimed to return 44.8mpg on the combined consumption cycle. Talk about having your cake and eating it, too.

Taking pride of place under the bonnet of the M division fettled four-door is the N57S, as BMW M division insiders like to refer to it. The highly complex and expensive to produce tri-turbocharged 3.0-litre in-line six-cylinder diesel engine – also destined for the upcoming X5 M50d and X6 M50d – provides BMW’s first dedicated performance diesel with the sort of instant-on performance and inherent entertainment value you usually only ever encounter from a high capacity petrol powerplant.

The aluminium block engine is a true technological tour de force, but despite BMW’s best efforts it still weighs 24kg more than the twin-turbocharged 3.0-litre unit it is based on. This places even greater weight over the front axle than the 535d – a car which it pips in overall output by 81bhp and 103lb ft at 376bhp and 545lb ft – the latter developed between 2000 and 3000rpm. And I never remember thinking the 535d lacks for punch.

What these bald figures fail to convey is the omnipresent energy. There’s no off-boost lethargy or waiting for it to come on song as engine speed builds. With the latest in high pressure, piezo valve guided direct injection together with a small, low interia turbocharger working in concert with a larger unit at low engine speeds to enhance the induction process, it delivers enormous shove and tremendous flexibility, and that’s just in the first couple of thousand revs.

Above 2700rpm, a second small turbocharger is engaged, providing additional boost pressure (up a maximum of 3.5 bar) and truly monumental in-gear thrust – the kind to make even the M5 feel, dare I say, a tad weak by way of direct comparison. Despite the M550d xDrive’s 1895kg kerb weight, it is heroically, epically quick.

Diesel engines aren’t supposed to respond to throttle inputs like this. At any revs, in any gear, the M550d xDrive simply flies. Pegged hard, its accelerative nature is nothing less than brutal. Nor are oilburners meant to accept revs with such unbridled enthusiasm. The new BMW engine feels totally at home operating beyond 4000rpm. In fact, it encourages you to. Peak revs are limited to 5500rpm.

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What’s more it sounds terrific. Unlike the M5, which receives a synthetic soundtrack, the M550d xDrive’s aural traits are genuine – although in a process that is gaining popularity right across the automotive spectrum, BMW does rely on the speakers to enhance their effect. The combination of engine and exhaust sounds is not unlike the original Audi quattro, with a deep warble at low revs and a wonderfully exuberant baritone wail up high.

For all its undoubted enthusiasm, epical thrust and aural delights, though, it’s easy to overlook perhaps the M550d xDrive’s most convincing traits – it’s superbly refined nature, relative economy and crushing long distance qualities. Mated to an upgraded version of BMW’s superb eight-speed automatic gearbox, the engine is not totally free of vibration but is smoother than any other high performance oilburner throughout its entire rev range, returns real world consumption not too far from BMW’s own claims and requires just 3000rpm at a heady 120mph cruise.

It’s big and heavy, but with the latest version of BMW’s four-wheel drive xDrive system apportioning drive to each corner it handles well, even in tricky weather conditions. It can’t quite match the M5 for overall dynamic ability: the electro-mechanical steering system lacks for consistent weighting and the ride is a little brittle (even in comfort mode) on certain surfaces. But with one determined stab of the throttle any deficiency is forgotten.

Should I buy one?

The M550d xDrive requires you to readjust any thoughts of traditional performance car values.

Don’t get too worked up, though. Like all existing four-wheel drive versions of the 3-, 5- and 7-series, the M550d xDrive is not planned to be produced in right hand drive. There is, however, a slim chance that BMW will place its brilliant new diesel engine in a rear wheel drive version of the M550d. Until then, the M5 remains the king, here in the UK at least.

BMW M550d xDrive saloon

Price: n/a; Top speed: 155mph (limited); 0-62mph: 4.7sec; Economy: 44.8mpg (combined); CO2: 165g/km; Weight: 1895kg; Engine: 6 cyls in-line, 2993cc, tri-turbo diesel; Installation: Front, longitudinal, AWD; Power: 376bhp at 4000rpm; Torque: 545lb ft at 2000rpm; Gearbox: eight-speed automatic

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fatboyfat 1 March 2012

Re: BMW M550d xDrive

enda1 wrote:

Considering that car companies are not charities they only run warranty schemes to make a profit you would be better off banking the £30 a month and if after 3 years nothing goes wrong you have £1080 in the bank.

At university I did a maths project on warranties and risk vs value and they just don't stack up

I know someone will tell a story about how something disastrously went wrong and got fixed under warranty but these are the minority and most people will shell out an extra £1080 for nothing

Same principle also applies to insurance, only difference it is a legal requirement.

Put it another way - if you have a 20 fag a week habit, thats more than the cost of knowing you have a hand it over and give it back fixed reassurance in your back pocket.

Selling service contracts all day long I know that in some cases - in fact a lot, people wont make use of them, but companies are also acutely aware now that the days of keep it for three years and buy a new one are over. People are looking to invest in something longer term.

Also think of £30 in relation to depreciation..........buying a newer car would lose you that anyway and still you have no idea of its reliability.

If I had a 3 year old car and was given the option of fixing my warranty at £30 per month for the next three years the blokes arm would have no skin left!

Boris911 25 February 2012

Re: BMW M550d xDrive

bomb wrote:

enda1 wrote:
I know someone will tell a story about how something disastrously went wrong and got fixed under warranty but these are the minority and most people will shell out an extra £1080 for nothing

I know exactly what you're saying but, for some people, having peace of mind is worth paying that £30 per month and that's not something you can calculate in a maths project.

Probability is in favour of just banking the money but £1080 won't go very far if something major goes wrong. Swings & roundabouts!

Good advice 'bomb'. You may get lucky as 'enda1' say's, but as an example of what can go wrong the controller unit for the 'M-DCT' transmission on the M3 is just shy of $4K! Add to that diagnosis of problem, installation tax etc, its probably a $6k repair all day long. That's about 4 grand sterling. Suddenly 30 quid a month looks like cheap insurance.

matsoc 25 February 2012

Re: BMW M550d xDrive

Submariner Redux wrote:

Looking at the Alpina D5 vs M5 test in the magazine this week, the M5 did 18 or 19 mpg on the test route and the D5 did 38 mpg.

So if you are a low mileage driver, then fair enough. But at my 25,000 miles a year, which is nothing unusual for 3 and 5 series drivers that extra fuel burn alone is the difference between £400 a month on fuel and £800 a month. Even if you are made of money, that fuel burn saving would finance the running of a very nice older petrol sports car for the weekend.

Yes, this is a good point. With today petrol price 25k miles a year are really too much for something like a petrol M5. But with a mileage of 10k a year the added money spent on fuel is not very relevant compared to the prices of the cars we are speaking. Anyway an Alpina D5 makes more sense to me than the M550d because it's rwd and looks better to my eyes.

Anyway if you take the economy into the equation the M550d could be the better car but the review was hinting that behind the wheel they offer comparable feeling. This is not true in my opinion.