BMW 520i vs BMW 850I

What's the difference?

Sleek and attractive in the city,  engaging on a country back road and with plenty of clever technology, the 5 Series sedan ticks all the right boxes as an executive express. If you can stomach the price hike, the six-cylinder 540i is our pick of the bunch.

Does the world really need a car as outrageously loud, over-the-top, exclusive and stupidly fast as BMW’s new 8 Series? Obviously not, but BMW clearly felt that its range, and its customers, could do with something like this. On paper, and even from the kerb, it seems a strange beast - luxurious and yet lightning quick - but from the driver’s seat it just instantly makes sense. And makes you smile. Scarily, there’s an even faster 8 Series Competition version to come…

Hardly a revolution, the 5 Series has instead undergone a few nips and tucks. But if it ain't broke and all that. It might not be the most head-turning offering, but the 5 Series sedan remains sleek, powerful and understated, and it is undeniably handsome on the road.

Its 8mm wider, 28mm longer and 2mm taller than the car it replaces, but it's also around 95kg lighter, thanks to its aluminium doors and boot and a clever magnesium frame for the instrument panel that saved another two kilograms. There's some other clever design elements, too. The kidney grille has active air flaps that open when extra cooling is required, closing when it isn't, reducing drag and helping accleration.

Inside, the 5 Series offers a beautifully crafted yet joyously understated cabin, with quality materials joining modern technology in a seamless way.

In terms of improving on the car it’s replacing, the new 8 Series pretty much smacks it out of the park. Time has not been kind to vehicles fitted with pop-up headlights and the previous 8 Series, which roamed the planet in limited numbers from 1989 to 1999, with now-unimaginable V12 engines, seems a strange-looking beast, with its tiny little kidney grille almost hiding beneath a BMW badge.

The new M850i is a simply stunning looking beast, particularly in Coupe form (the Convertible is not ugly, but it just doesn’t look as complete). Extremely wide and menacingly low, it seems to loom over whatever patch of ground its parked on, giving off an air of magnificent malevolence.

It looks fantastic when followed from behind, but it’s the front view - featuring the thinnest headlight design ever seen on a BMW for a sleek, Iron Man-like face - that really grabs your attention.

Proportion, poise and big old 20-inch wheels give it plenty of presence, while the way the glasshouse tucks in at the rear only magnifies its powerful hips.

BMW has also thrown plenty of design flair at the interior, where you’ll find the unusual yet fabulous-feeling glass gear lever (there’s more of this sparkly, cut-crystal-like stuff on the volume knob, Start button and iDrive controller).

Not only does it feel truly unique and expensive in your hand, but it has an 8 buried beneath it, which shifts and shimmers as you try and see it through the many angles of the glass.

Elsewhere, the cabin is swathed in merino leather and feels undeniably classy, with a touch of modernity via its big screen, but it’s still not quite as beautiful as the cockpit you’d find in an Audi of a similar price. Close, but not quite.

This is a full-size sedan, and every seat feels spacious and airy. The sloping, slightly coupe-style roofline does cut into headroom in the back, but human-sized people will have little trouble, even sitting behind a tall driver.

Each trim offers two cupholders in the front, with another two housed in a pull-down divider that seperates the rear seat. And there's two ISOFIX attachment points, one in each window seat in the back. 

The 5 Series' boot opens to rival a surprisingly sizeable storage space, offering 530 litres with the 40:20:40 rear seats in place.

At the very least, you’d have to say the 8 Series is fit for purpose. The seats are hugely comfortable for long journeys, so that’s practical, there’s a handy tray for your phone, where it will be wirelessly charged, and there are two cupholders in front of that, and storage for bottles in the doors.

No human larger than primary school age will ever sit in the back, so there’s not a lot going on back there.

In terms of boot space, it’s reasonably capacious at 420 litres, or 350 litres for the Convertible.

It can be hard to use the word “value” when talking about a car that costs north of $270,000, and keep in mind that this 8 Series is thus even more expensive than a Porsche 911. And a car has to be very good indeed to be worth more than one of those.

We would respectfully suggest that this BMW is pitched a little high in price terms. 

Staggeringly, while the standard equipment list is lengthy and the inclusions are high end, you can still spend even more on options, and fairly easily push the price past $300,000 - Pure Metal Silver pain, for example, will set you back $10,400, while a pack of external carbon bits will hit you for another $7500, or $6,600 for the Convertible.

Standard equipment includes, deep breath, 20-inch M-branded light-alloy wheels, a tyre-pressure indicator, M Sport Brakes, M Sport Differential, Adaptive M Suspension Professional with Integral Active Steering, Active anti-roll stabilisation, Comfort Access including a kick-open tailgate, wireless phone charging, Soft Close Doors, BMW Crafted Clarity Glass Application, Driving Assistant Professional, Parking Assistant Plus, including 3D View and Reverse Assistant, Laserlights, a 12.3-inch digital instrument cluster and a 10.25-inch Control Display, metallics, paint, merino leather upholstery, heated steering wheel and arm rests, and seats, a 16-speaker harmon.kardon sound system, a Head-Up Display and the hugely pointless Gesture Control. 

The Convertible model also gets an Air Collar, to keep your neck warm when the roof is down.

The hunt for efficiency sees all but the most expensive 5 Series models equipped with four-cylinder engines, including the entry-level 520d, which is fitted with a 2.0-litre diesel unit that will produce 140kW at 4,000rpm and 400Nm from 1,750rpm. That's enough to push the cheapest 5 Series to 100km/h in a not particularly inspiring 7.5 seconds, topping out at 235km/h.

The cheapest petrol, the 530i, arrives with a turbocharged 2.0-litre engine good for 185kW at 5,200rpm and 350Nm from 1,450rpm. That will see you clip 100km/h in 6.2 seconds and push on to a limited top speed of 250km/h.

The turbocharged six-cylinder feels right at home in a car this size, with acceleration effortless and freeway overtaking manoeuvres an absolute breeze.

The 530d introduces the first six-cylinder engine, a 3.0-litre unit that will produce 195kW at 4,000rpm and an impressive 620Nm from 2,000rpm. That's enough to knock off the sprint in in 5.7 seconds and offers a top speed limited to 250km/h.

Finally, the top-spec petrol, the 540i, will produce 250kW at 5,500rpm and 450Nm from 1,380rpm from its 3.0-litre turbocharged straight-six engine. Those are healthy numbers, and enough to welcome 100km/h in a sprightly 5.1 seconds before topping out a limited 250km/h.

Every model is paired with an eight-speed torque converter automatic transmission.

Truly, there is one impressive engine sitting under that big, hulking bonnet. The M-fettled 4.4-litre V8 has two turbochargers located inside the V of the block for “immediacy of response”, and they certainly deliver that.

Peak power of 390kW is delivered between 5500rpm and 6000rpm while its hefty 750Nm of torque is on song, for effortless overtaking, from 1800rpm all the way to 4600rpm.

Looking at those rev figures it’s clear to see that you are initially launched by a huge wave of torque and then, while you’re still drawing breath, the power really kicks in. 

All that grunt equates to 0 to 100km/h in just 3.7 seconds, which is very fast indeed, and you also get to enjoy a growly, guttural soundtrack, thanks to the standard Sport Exhaust.

The Convertible has the same engine with the same figures, but it’s slightly heavier and thus takes 3.9 seconds to hit the tonne. Which is still stupidly fast for this much car.

BMW quotes a combined 4.3 litres per hundred kilometres from the 520d, which will also spit out 114g per kilometre of C02. The 530d lifts that number to 4.7 litres per hundred kilometres (which seems a small price to pay for all that extra torque), with C02 pegged at 124g per kilometre. Both diesels get a slightly smaller tank, at 66 litres.

The 530i will sip a claimed/combined 5.8 litres per hundred kilometres, with C02 emissions a claimed 132g per kilometre, while the big 540i requires 6.7 litres per hundred kilometres, with C02 pegged at 154g per kilometre. Both petrol models get a 68-litre tank and require 95RON fuel.

Good luck ever matching these figures, with all that V8 temptation beneath your right foot, but the claimed number, at least, is 10.4 litres per 100km for the Coupe and 10.6 for the Convertible. During our launch drive we would have been absolutely nowhere near those figures.

BMW's pre-drive briefing was so technology focused we half expected the black turtle neck and dad jean-wearing ghost of Steve Jobs to emerge from behind a curtain clutching an iPad. Only a minuscule portion was dedicated to the cars' drivetrains, with BMW instead hammering home autonomy functions, technology upgrades and the fact that its car was a preview to "the future".

But once we'd slipped behind the wheel of the all-new 5 Series, it all started to make more sense. Having briefly sampled three models (the 530i, 530d and 540i), we can safely report there's nothing particularly revolutionary about their on-road behaviour. That's not necessarily a bad thing - they do everything you could ask of a car in this bracket. They're mostly smooth and always quiet, the new chassis has done nothing to dampen engagement when you start to ask a little more of it, and it's generally a luxurious experience. But then so was the old car.

But what's new is the technology poured into the 5 Series. Every car gets what BMW is calling its personal co-pilot, for example, which is a set of tricky systems (there's six cameras, five radar sensors and 12 ultrasonic sensors scattered around the car) that work with the active cruise control and allow the car to be driven completely autonomous for 30-second intervals. Now, it's not quite as advanced as some of its competitor's systems - it can't change lanes for example - but if you're out on a country road or on a highway, it will stay within its lane, turn around corners and keep up with the traffic, even if they stop in front of you.

This is a full-size sedan, and every seat feels spacious and airy.

While the cheapest diesel model has historically been the best seller, BMW is hoping the new 530i will prove the most popular this time around. And while you couldn't describe it as fast, the power from its four-cylinder engine is ample for all that will likely be asked of it, and it feels sorted and composed on  more challenging roads. It's a smooth and comfortable ride, too, even with the optional 20-inch alloys fitted, though that's undoubtedly thanks to the adaptive dampers and ever-changing dynamic ride function, both of which are fitted as standard. In fact, we're yet to drive a car without those options fitted, so we're forced to reserve judgement on the as-standard ride quality of the cheaper models.

Be warned though, none in the 5 Series range offer the disconnected and perfectly smooth conveyance you might find in some true luxury offerings, and you'll still know when you're diving into deep pockmarks in the road. But the trade off is a an engaging ride and steering set up that always feels planted, with enough feedback to ensure you feel connected to what's happening beneath the tyres. And that's a trade we're more than willing to make.

Step up to the 540i and things take a much sportier turn. The turbocharged six-cylinder feels right at home in a car this size, with acceleration effortless and freeway overtaking manoeuvres an absolute breeze. And while we didn't find roads quite brutal enough to really test the active anti-roll bars housed at each axle, there's a wonderful and stable flatness to the way the biggest petrol handles corners.

It's not cheap, but thanks to the bigger engine and sorted dynamics, the 540i feels most like a 5 Series probably should.

There is a sizeable distance between driving a small, lithe sports car that can sprint from 0 to 100km/h in a scorching 3.7 seconds, and then piloting something that feels as large, and louche, as a cruise ship that can do the same thing.

Accelerating in the M850i is an experience that can only be described as hilarious. There’s just so much mass attempting to move so quickly that it defies belief. The way the nose rears into the air, and the rear end seems to dip towards the ground, brings to mind a bucking bronco, although a feisty polo pony would probably be more appropriate.

It’s easy to see why this car is all-wheel drive rather than the traditional BMW rear-driven layout, because there’s just no way you could get all that grunt to the ground with two wheels, or not without some serious power oversteer issues.

For a car that weighs more than 1.8 tonnes, the 8 Series is surprisingly fluid and involving on winding stretches of road. It feels hunkered down and hammered into the road, which is less of a surprise, but the steering is so perfectly weighted and the power delivery so well calibrated that it really encourages you to push on, and rewards you sense of adventure with smile-widening pace.

It’s quite something to suggest of a car that costs a quarter of a million dollars, but the M850i actually exceeds your expectations in terms of driving joy. On paper, it looks like a straight-line bully, or merely a very grand grand tourer, and it does eat up the miles on a freeway with class and ease, but when you want to point it at a mountain pass, it excels there as well.

We drove the new 8 Series back to back with BMW’s also-new Z4, and what really stood out was not just the gulf in power and poise, but the huge difference in the ride/handling balance.

The M850i really can soak up the worst our roads can throw at it with aplomb, while still making you feel connected to the ground beneath you, and inspiring confidence, and its abilities really did make the Z4 feel very brittle and hard indeed.

To be fair, we didn’t get to throw this big luxo-barge at any sections of really sharp S-bends, or 35km/h corners, and no doubt it would be challenge for it to change direction quickly, but through fast sweepers it really does excel.

And as far as its grand-touring design brief, it absolutely nails it.

There’s no ANCAP rating to go on for this car, and nor is there anything similar out of Europe to give us guidance, but you do get eight airbags - front, full-length sides and head protection on the sides and in headliner, plus knee airbags for the front seats.

The 8 Series also gets Driving Assistant Plus as standard, which includes Active Cruise with full Stop&Go function, which BMW considers to be “full AEB”, meaning it will bring the car to a standstill, automatically, when required.

The BMW 5 Series is covered by a three year, unlimited-kilometre warranty, and requires condition-based servicing (rather than a pre-defined service interval).

You can also prepay your maintenance costs for five years/80,000kms, with prices ranging from $1,640 for the basic package, and climbing to $4,600 for the all-inclusive option.

BMW is sticking with its not-very-industry-leading three-year, unlimited-kilometre warranty, and says its customers are happy with that, rather than the five- or seven-year warranties some other companies offer. When you’re paying this much for a car, it seems a trifle mean, frankly.

Like all modern BMWs, the servicing requirements for your M850i are controlled by the Condition Based Servicing (CBS) system, which means that “advanced algorithms monitor and calculate the conditions in which a vehicle is used, including mileage, time elapsed since its last service, fuel consumption and how a vehicle is driven”. 

That information allows the car to decide for itself when an annual vehicle inspection or oil service is due.

BMW offers two fixed-price servicing plans, under its BMW Service Inclusive (BSI), which is available in two packages: Basic - $2,290 for five years/80,000km or $5,170 for Plus.