BMW M850i Convertible

Scope of this guide

This guide is scoped to the BMW M850i xDrive Convertible, the G14 generation 8 Series open car with the 4.4L N63 twin-turbo V8 petrol engine, 523 bhp, an eight-speed automatic gearbox and all-wheel drive, built at the BMW Group plant in Dingolfing, Germany. It covers both the original 2019 cars and the cars updated in 2022. It is not a guide to the M850i xDrive Coupe or the Gran Coupe, to the 840i and 840d convertibles with six-cylinder engines, or to the M8 Convertible, which has its own, more powerful V8. Where those cars differ we say so, because an advert that says only "BMW 8 Series" can mean any of them.

We have not driven this model for this article. Everything here comes from three cited sources: BMW Group's own press release on the start of Convertible production, PistonHeads' May 2019 UK review of the car, and the government recall checker. We also used PistonHeads' unveiling report of 1 November 2018, Auto Express's January 2023 review of the updated car, a copy of BMW's January 2022 update release hosted by a third-party site, and Wikipedia. We say where a point rests on a source we could read only in part. Prices are history, not valuations.

The figures at a glance

• Engine: 4.4L N63 twin-turbo V8 petrol, 4,395 cc, mounted at the front.
• Power: 523 bhp. BMW quotes 530 PS, which is 390 kW. Our conversion is 530 divided by 1.01387, about 522.8, so 523 bhp. PistonHeads prints 530hp and Wikipedia lists 530 PS as 523 hp, so the labels "hp" and "bhp" in the press are the same figure in different words. Peak power arrives between 5,500 and 6,000 rpm.
• Torque: 750 Nm, which PistonHeads prints as 553 lb ft, available from 1,800 to 4,600 rpm. Auto Express says the maximum is reached before 2,000 rpm.
• 0-100 km/h: 3.9 seconds, BMW's claim for the Convertible at launch. PistonHeads' unveiling report labels it 0-62 mph, so the metric and imperial figures are treated as the same here, which is a simplification. Other figures exist, covered below.
• Top speed: 250 km/h, electronically limited, which PistonHeads prints as 155 mph.
• Drive: all-wheel drive through BMW's xDrive system and an eight-speed automatic gearbox, Steptronic Sport in BMW's wording, with shift paddles on the steering wheel.
• Weight: 2,090 kg according to PistonHeads, which is 125 kg more than the Coupe. Auto Express says just over two tonnes.

Reveal, launch and the model years

PistonHeads reported the Convertible's official unveiling on 1 November 2018, a day after pictures leaked on a Belgian website. BMW's press release is dated 7 November 2018 and says series production had begun in Dingolfing, with a market launch in March 2019 for two model variants, according to the search summary we could read. PistonHeads at the time said sales would begin in April 2019 and that prices started at 83,270 pounds, an entry price that was not the V8 car: PistonHeads' May 2019 review lists the M850i xDrive Convertible at 107,100 pounds.

Our catalogue has held 2018 as the first year. We now use 2019, because that is when customers could first buy one, and because Wikipedia's model table lists the M850i xDrive as 2019 to 2026. The reveal and first production were in 2018, so a person who counts those would pick 2018, and an advert for a very early car may be registered either way. The Convertible was the second body style of the second-generation 8 Series, after the Coupe and before the Gran Coupe, which Wikipedia says was announced in June 2019.

Is it still on sale

No new G14 is being built. Wikipedia says BMW announced in autumn 2025 that the 8 Series would end without a direct replacement, and its infobox gives 2026 as the end of production. We also saw a search summary of BMWBlog reporting in November 2024 that Convertible and Gran Coupe production would end in April 2026, and another summary quoting BMW as saying the car reached the end of its standard product lifecycle. Reports differ on the exact month and on the final build, and we could not read a BMW page that gives it, so our catalogue records 2026 and a person should treat that as the best available year, not a confirmed date. For a buyer this means a closed model line, and the used market, not this guide, will set prices.

Power, PS and the label problem

BMW works in kilowatts and metric horsepower. The 2022 press release uses kW and hp in its own text, and UK road tests use bhp. They are three ways of writing one engine rating. A quick check you can do: 390 kW multiplied by 1.341 is about 523 mechanical horsepower. If an advert says 530 hp, it is quoting the metric figure and the car is the same one. If it says anything well above 530, it is probably an aftermarket tune or a different model such as the M8, so ask what has been changed and whether the supplier has insured and documented it.

Why the 0-100 time varies

The Convertible's acceleration figure depends on who is quoting it. BMW's launch figure, reported by PistonHeads, was 3.9 seconds. The PistonHeads review of May 2019 quoted 3.7 seconds for 0-62 mph and described it as the same as the Coupe, and PistonHeads says it was keeping the Coupe's claimed time. Wikipedia's table also lists 3.7 seconds. Auto Express's 2023 review of the updated car printed 4.1 seconds for 0-62 mph and said that was 0.2 seconds slower than the Coupe, which implies a Coupe figure of 3.9, not 3.7. These numbers describe the same engine and the same output, so the differences come from different claims for different model years and body styles, not from a changed engine. We use 3.9 seconds for 0-100 km/h as the launch claim and note that two other sources disagree. We also saw a 3.8 second 0-60 mph figure for the US market in a search summary only. None of them is a measured test of a used car.

What changed in the 2022 update

BMW updated the 8 Series range in early 2022. According to the release text we read, all models gained an M sports package as standard, a redesigned front end with an illuminated kidney grille bearing an M logo on the M850i, M exterior mirrors, standard Merino leather upholstery, four new paint colours and a larger 12.3-inch central display, up from 10.25 inches. The adaptive LED headlights were standard, with laser light optional. The V8 was not changed: Auto Express says the engine is unchanged at 523 bhp and 750 Nm, and the release carries no change in power. Fuel figures moved to the WLTP test: BMW lists 11.0 to 10.7 litres per 100 km and 249 to 243 g/km for the updated Convertible, and Auto Express matched a claimed 25.9 mpg. PistonHeads in 2019 printed 28.2 mpg and 229 g/km, a different, older test cycle, so do not compare them directly. We found no mild-hybrid system on the V8: the release names 48-volt mild-hybrid technology for the diesel and does not mention it for the V8.

Roof, boot and weight

The cloth soft top opens or closes in 15 seconds and works at up to 50 km/h (31 mph), according to PistonHeads and BMW. The roof needed thicker sills, and PistonHeads says that is part of why the open car is 125 kg heavier than the Coupe. It says the structure feels stiff, with no scuttle shake, and that the ride is good but the run-flat 20-inch wheels, 245 section at the front and 275 at the rear, thud over bumps. It also says the steering and brake pedal give little feel and that the car is more grand tourer than sports car.

Auto Express says the boot holds 440 litres with the roof up and 350 litres with it down, with a narrow opening and a hard-to-reach front section. A wind deflector sits in the boot, and the reviewer found the neck warmer weak in very cold weather. PistonHeads calls it a luxury soft-top grand tourer rather than a sports car, in a good way.

What to check before buying

• Confirm the model and the engine: 4.4L N63 twin-turbo V8 petrol, 530 PS, M850i on the boot and in the instrument cluster, not an 840i with an M Sport package.
• Operate the roof several times with the engine running, open and closed, at a standstill and again just under the 50 km/h limit if the seller allows it. Look for slow cycles, warning messages, creased fabric, water marks in the headlining and wet carpet.
• Check the run-flat tyres for sidewall damage and ask what they cost to replace. Our sources give the sizes, not a price.
• Ask for a full service history from a BMW dealer or a specialist. We found no sourced reliability or running-cost data for this car, so we make no claims about it, and the checks above are our own suggestions.
• Check for any outstanding software updates and for evidence that every key, display and driver aid works.
• Look at the wind deflector, the neck warmers and the seat heating, which are small items that are easy to overlook on a test drive.
• Establish the car's age and update status: pre-2022 cars have the older front end and the smaller display.
• Check for aftermarket tuning or exhaust changes, since a car above 530 PS is no longer the car in this guide.
• Run the registration through the recall check described below.

Recalls and the DVSA check

We did not run the government checker, because it needs a registration number or the make, model and year, and we are not looking at a specific car. The page says the MOT checking service shows outstanding safety recalls for a car with a registration, while the vehicle recalls checker needs the make, model and year. It also says non-safety recalls come from the manufacturer directly. We found no recall notice for the car in the sources we read, which is not a clean bill of health. BMW's own UK and Irish pages would not load for us, so we could not check them, and we did not try to get around that.

About the photograph

The picture at the top of this page shows a white 2019 M850i xDrive Convertible with the roof closed, photographed in Leamington Spa, England. It is an early car from before the 2022 update, and the roof is up, so it shows the shape rather than the open-air view. We cropped and resized the original, and we blurred a number plate on a different car in the background. The photographer's own picture already had the car's plate blanked.

Verdict

The BMW M850i xDrive Convertible is a heavy, quick, well-insulated grand tourer: 523 bhp, 750 Nm, a claimed 3.9 seconds to 100 km/h, 250 km/h limited, all-wheel drive and a soft top that folds in 15 seconds. The 2022 update changed the looks and the screen, not the engine. It is a closed model line, the date of its end is not firmly sourced, and our evidence on ownership cost is thin. Insist on the roof test, a full history and a recall check, treat every published figure as a claim, and remember that we have not driven it.