New BMW M850i xDrive 2023 review

Verdict

The BMW M850i xDrive Cabriolet might be a bit of a sweet spot in the 8 Series range. The engine suits the character of this model more than the performance-focused M8 and it’s made all the more engaging thanks to the soft-top roof. The interior might be feeling its age, but strong equipment levels help to make up for this. Practicality hinders the M850i’s grand touring qualities slightly. 

Personalised licence plate companies might not be huge fans of the latest BMW 8 Series, given a ‘22’ plate is probably the most obvious indication this is indeed a facelifted model. 

There are subtle tweaks to the exterior of the new ‘8er’ to make note of. The M Sport body pack is now standard with redesigned bumpers front and rear, larger air intakes at the front and new detailing in the grille which on this model features BMW’s “Iconic Glow” package. 

Overall, the 8 Series still has plenty of presence on the road although you could argue the design has softened in the past few years with other big BMWs gaining increasingly large grilles and split headlights.  

Adding to the theatre of this M850i xDrive model is its convertible roof. The soft-top grand touring segment has lost the Mercedes S-Class convertible since the 8 Series returned for its long-awaited second-generation, but there’s still the Aston Martin DB11 Volante, Porsche 911 Turbo Cabriolet, Bentley Continental GT C V8 and of course the new Mercedes SL to contend with.

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While it might not be the full-fat M8 Competition, the M850i still gets plenty of M logos dotted around inside and out. On the face of it, you wouldn’t say they’re undeserved, either. As before, there’s a 4.4-litre, twin-turbocharged V8 with 523bhp and 750Nm of torque - enough to keep up with plenty of the aforementioned rivals. 

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Helped by a four-wheel drive system, the M850i will accelerate from 0-62mph in 4.1 seconds, 0.2 seconds shy of the Coupe model. In a car as large and as heavy (just over two tonnes, if you must know) as the 8 Series it’s a pretty impressive figure. 

BMW hasn’t really fiddled with the 8 Series in terms of its powertrain and chassis. The model we tested has the optional ‘Ultimate pack’ which adds BMW’s ‘M Adaptive Suspension Pro’ set up with air suspension and four-wheel steering.

Despite the presence of 20-inch wheels, the M850i’s suspension is adept at turning long journeys into relaxing cruises. Our test included a run from Lincolnshire to the south coast and back, which the 8 Series completed without fuss - including some typically nightmarish traffic on the M25.

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The soft suspension, coupled with the comfortable seats (BMW M division’s carbon-backed chairs aren’t an option, thankfully) are only part of the M850i’s long distance capability. There’s a long bonnet stretching out in front, but the 8 Series is easy to place on the road, despite being almost as wide as a Range Rover. A little road noise filters through the soft-top as you’d expect, but it’s still fairly hushed in there. 

It might not be an out-an-out M car, but the M850i holds its end of the performance-based bargain when the roads get twisty. It sometimes feels a little strange threading a car the size of the 8 Series along some B-roads but there’s plenty of encouragement to do so. BMW says the cabriolet is 97 per cent as stiff as the coupe and many would struggle to notice the slightly more flexible body. 

Several drive modes - Sport and Sport Plus, Comfort, Eco Pro and Adaptive - can alter things like the steering, transmission, throttle mapping, damping and even the exhaust note (which can be augmented through the cabin’s speakers). It’s worth trying out the settings because BMW has actually gone to the effort of making each one feel different, which is something not all manufacturers do. 

The steering itself is sharp. You’ll notice a little vagueness off centre but it’s quick to load up and gives you plenty of confidence that the front of the car will respond to inputs almost immediately. The added bonus of rear-wheel steering gives the M850i a real sense of security in the corners. 

It’s also surprisingly easy to forget how much the 8 Series weighs when you’re pushing it around your favourite bit of road. The four-wheel drive system means there’s oodles of grip, although it’s difficult to tell just how much power is being distributed to each axle. The M850i xDrive performs its best work with precise, measured inputs. The huge M Sport brakes fitted to this car aren’t grabby either, they provide a particularly nice balance between power and sensitivity.   

As we’ve said, the V8 is unchanged and for the M850i’s application this is perfectly fine. Thanks to its twin scroll turbocharging, maximum torque is reached before 2,000rpm and maximum power sits between 5,500 and 6,000rpm. It would be a disservice to call the engine lazy, because it suits the nature of a cosetting, large convertible grand tourer. 

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The throttle response is adjustable, but it never engages like a true sports car. It’s more than capable of giving you the instant torque needed to blitz a motorway overtake, but mid-corner throttle tweaking is more BMW M car territory. 

Although the M850i comes with a wind deflector in the boot, it’s perfectly usable without. Sub-zero temperatures were a tough test for the neck warmer - which was rather pitiful, but the heated seats and steering wheel managed to get toasty within a minute. 

With the roof down (which takes all of 15 seconds at speeds of up to 30mph) and at motorway speeds you can have a relatively quiet conversation - this might be a little more difficult for rear passengers, if they’ve managed to fold into the cramped back seats. With the roof down you’d think the standard-fit sports exhaust would become a real party, piece but it’s a little diluted in the M850i, although there is at least a characterful distant rumble from the V8. A little quirk of the M850i is that you’re a little aggressive with the throttle at low speeds, the turbochargers emit a strangely high pitched whistle - almost like a supercharger.

Like most convertibles the roof folds away into the boot, which decreases storage from 440 litres to a still respectable 350 litres. The only problem is the opening is very thin and the front is borderline unreachable due to the ingress of the roof; an errant orange or apple falling out of the weekly shopping bag could become irretrievable here. 

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We’ve said the exterior received minor design tweaks and BMW has also not exactly revolutionised the interior either. It’s ergonomic enough in that traditional BMW way, but lacks the sparkle the new all-electric ‘i’ models have (although the gear lever and iDrive controller are crystal).

The current 8 Series range kicks off at £81,160 for the 3.0-litre straight-six 840i, but this M850i xDrive costs a whopping £119,200 (excluding our car’s £15,000 worth of extras). The M850i’s demeanour certainly lends itself to having the V8 engine and our car was relatively economical considering the power available (we matched BMW claimed 25.9mpg). 

You can quite easily spec the M850i convertible towards £130,000, but even with this figure in mind, it’s still a fair chunk cheaper than rivals from Porsche, Aston Martin and Mercedes, all the while still exuding all the attributes you’d expect from a car in this segment.

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