2019 BMW M850i Convertible performance review

What happens if you’ve always wanted a powerboat but can’t stand water? Well, you could buy a BMW M850i Convertible.

This isn’t to suggest the handling of this flagship droptop is in any way nautical – in truth it’s quite the opposite – but in sound and shape it’s redolent of the sleek wedges you see skimming through the surf with massive outboards hanging off the back.

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At 4.85m long, 1.9m long and weighing in at over two tonnes (2015kg) the M850i Convertible is a big bus, but defies its size thanks to some tricky technology and a hefty helping of good old-fashioned horsepower. Under the bonnet is a 4.4-litre twin-turbo V8 producing 390kW from 5500 to 6000rpm and a mountainous 750Nm spread from just 1800rpm all the way to 4600rpm.

It’s a monster of an engine. According to the claimed figures the 165kg-heavier Convertible is two-tenths slower to 100km/h than the Coupe, but 3.9sec certainly isn’t hanging about – you’re likely to be too busy hanging on to notice. Then there’s the noise.

Deep and guttural with shift-cut cracks and over-run crackles, it’s the sort of soundtrack more commonly associated with AMG. BMW’s ‘standard’ V8s have sounded better than their M Division counterparts for a few years now and the M850i continues that trend.

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Sadly dropping the roof – a process that takes 15 seconds and can be done at up to 50km/h – doesn’t further reward your ears. Whether there’s a degree of synthesised noise in the cockpit or the soft-top roof filters out some of the less attractive acoustics, with your hair in the breeze the exhaust sounds a bit flat and uninspiring, especially at higher rpm. Is it coincidence that the M850i sounds best during short blasts away from the traffic lights?

This is a shame as when you really get stuck in this land yacht displays a remarkable amount of dynamic talent. Accurate steering, substantial levels of lateral grip, strong brakes and all-wheel drive traction ensure corners can be dispatched at a tremendous rate, but it’s the all-wheel steering that endows the M850i with an agility at odds with its size.

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Up to 72km/h the rear wheels point in the opposite direction to the fronts, while above that speed they point in the same direction – in both cases to a maximum of 2.5 degrees – to improve response and stability respectively. Done poorly it can make the car feel nervous or unnatural, but in this case it feels to remove 300-400kg from the kerb weight. The ride is good, but perhaps not as plush in Comfort as might be expected in a $281,900 grand tourer?

Inside the 8 Series will be familiar to anyone with experience of an X5 with new digital instruments, the latest iDrive infotainment system and Swarovski crystal gearknob, along with a number of welcome heat sources – steering wheel, neck scarfs and seats. Unfortunately, poor packaging has carried over from the previous 6 Series, with the 8’s rear accommodation limited to children at a stretch.

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The M850i’s Convertible price tag is as substantial as its presence on the road, but if you’re in the market it’s worth considering over the Coupe. Any dynamic compromises occur at a pace few will venture to achieve and there’s the added benefit of unlimited headroom should you have the desire. Just remember to stay out of the water.

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2019 BMW M850i CONVERTIBLE SPECS
Engine: 4395cc V8, DOHC, 32v, twin-turbo
Power: 390kW @ 5500-6000rpm
Torque: 750Nm @ 1800-4600rpm
Weight: 2015kg
0-100km/h: 3.9sec (claimed)
Price: $281,900

Like: Monster V8; presence; dynamic prowess
Dislike: Mega money; packaging

Rating: 4 out of 5 stars