BYD Sealion 8 vs BMW 428i

What's the difference?

There’s no denying the value the BYD Sealion 8 Premium offers as it packs a lot in for the price. Its efficiency and inoffensive looks add up to a good package and reflect what it does well. That said, the underwhelming driving experience and clunky media system are noticeable. Whether they're deal breakers is up to you.

The 4 Series line offers three distinct points of difference from the more traditional 3 Series, each with their own attraction. The sharpening of the sticker prices and the additional spec helps their cause as well, with the 430i Coupe probably our pick of the range. The 440i is the firecracker of the group, while the 420d is also worth a look, thanks to its value and prodigious torque output.

The Sealion 8 is a big unit, and its design leans more towards soft and rounded than sharp. There’s a sense of restraint with its pillowy panels, smooth curves and flush door handles all contributing to a clean, almost clinical look.

The 21-inch wheels add a bit of presence, as does the full-width LED light bar with its braided design. But overall, it doesn’t try too hard to stand out. It’s inoffensive - clean and easy on the eye, but it stops short of having any sense of identity.

Inside, the cabin carries that same restrained approach. There’s black leather upholstery, some interesting geometric detailing through the panels and speaker grilles and a generous use of soft-touch materials throughout.

The large displays and panoramic sunroof help lift the space, giving it a premium feel, but more importantly, it’s just a comfortable, easy place to spend time. Which, for a family SUV, arguably matters more than anything else.

No external changes to the 4 Series' bodywork have been affected  for  this midlife refresh, but there have been plenty of tweaks to the standard equipment offerings right across the board.

Up front, storage and general usability are well thought out. There’s a handy shelf tucked underneath the centre console with two USB-C ports, while a tray above houses the fast wireless charging pad. You also get a sunglasses holder, two cupholders and decent-sized bottle holders in the doors, so it’s easy to keep things organised.

Seat comfort is a highlight, and the overall layout is clean and easy to live with, but the same can’t be said for the multimedia system. While the graphics are sharp and the touchscreen is responsive, functionality isn’t always its strong suit. Wireless Apple CarPlay and Android Auto are included, but CarPlay required reconnecting on every drive during testing and the digital radio and phone calls experienced noticeable signal dropouts. It’s the kind of friction that chips away at the day-to-day experience and starts to feel out of step with how polished the rest of the cabin is.

There’s also a heavy reliance on the screen for core functions. Climate control is integrated, which is fairly standard, but so too are things like headlight controls. It might suit those who are used to navigating everything through a screen, but needing to dig through menus to adjust something like auto high beam on the move feels like a step too far. Bring back buttons.

The second row is where the Sealion 8 really leans into its family-friendly brief. Space is generous, with enough width to comfortably accommodate three adults and the flat floor helps here too. There are three top tether points and two ISOFIX mounts, while charging is covered by a USB-A and USB-C port.

Amenities are a standout. The outboard seats mirror the front with heating, ventilation and massage functions, which quickly become a favourite, alongside dedicated climate controls, roof-mounted air vents and multiple cupholders. A set of sunshades would round things out nicely, but it’s otherwise a very accommodating space.

Access to the third row is less impressive. The manual slide and tilt mechanism feels a little heavy and fiddly to operate and the space itself is best reserved for kids. In practice, that means younger passengers will likely take the path of least resistance, as mine did and simply climb over the second row instead.

Amenities are fairly basic, with directional air vents and cupholders, but there’s no charging provision back there. You do, however, get two top tether points and ISOFIX mounts, which will be a plus for larger families.

Around the back, the boot is a practical, usable space with a wide opening and flat loading floor. With all three rows in place, there’s 270L on offer, which is enough for a few school bags or a grocery run, expanding to 960L with the third row folded. There’s no spare tyre, just a repair kit, which may be a consideration for regional drivers. A 12-volt socket and powered tailgate round things out in this grade.

Two-doors are never the most practical devices, but the 4 Series Coupe and Convertible duo make a decent fist of it for front-seat passengers. There are bottle holders in both doors and a pair of cupholders in the centre console, along with a large lockable glovebox.

The centre bin is, however, quite shallow, and houses the car's single USB port inside it. There is covered storage under the dash for smaller items, and a small rubber-lined tray that the current crop of phones has outgrown.

The rear seating in the Coupe is reduced to almost a formality, especially if the front seat passengers are tall and the front seats are set back, while the sloping roofline reduces head space quite considerably. A centre armrest contains a pair of cupholders, and there are small side pockets.

Rainy conditions precluded us from trying the Convertible's metal folding roof, but the rear seat space restrictions also apply here. Its 370 litres of boot space is roomy enough for a drop-top, while a clever lifting function raises the folding roof structure up by about 300mm to allow luggage to be stowed under the panels when the roof is down. Capacity drops, though, to just 230 litres.

The Gran Coupe, on the other hand, is the most practical car in the entire 3 and 4 Series line-up outside of the 3 Series Touring wagon. With a large, flat load area, and a hatch-like tailgate, the Gran Coupe can swallow 480 litres of gear with the seats up and an impressive 1300 litres with the seats lowered.

Face-level rear vents, more head and backseat legroom – not to mention the fact you don't have to squeeze into the rear past the front seat – makes the Gran Coupe a most useful device, and it's little wonder it's the most popular variant of the three.

Entry into the 4 Series world now stands at $68,900 plus on-roads for the petrol 420i Coupe and Gran Coupe, and tops out at almost $118,000 for the 440i Convertible.

Both the 420i and 420d have been boosted by the addition of adaptive M dampers, a heads-up display, powered folding rear-view mirrors, lane-change warning, driving assistant and BMW's surround view camera with top and side views.

BMW claims the extra kit is worth just over $8000. Leather seats, sat nav, BMW's ConnectedDrive Emergency call system, bi-Xenon headlights and reversing camera are also featured. An eight-speed automatic transmission is offered as stock, but a six-speed manual can be optioned at no cost.

The diesel version costs an additional $2200 over the petrol powerplant.

Stepping into the 430i, the M Sport Package is offered as standard, with the Luxury line, which includes a leather-trimmed dash, a no-cost option.

Additional standard equipment over the outgoing 428i includes 19-inch M rims, heads-up display, lane change warning, driving assistant and surround view camera. The 430i also gains electric lumbar support for driver and front passenger seats and a nine-speaker stereo system over the base 420i.

Finally, the range-topping 440i scores a heads-up display, lane change warning, driving assistant, surround view camera, adaptive LED headlights, leather dash, front seat heating, high beam assist, active cruise control with stop and go function and parking assistant over the outgoing 435i.

Over the 430i, the 440i also gets variable sport steering, a Harman/Kardon surround sound system with 16 speakers, a leather instrument panel (with M Sport Package), ConnectedDrive internet and concierge service, and air collar neck-warming ducts for the 440i Convertible.

The BYD Sealion 8 Premium is all-wheel drive and pairs a 1.5-litre, four-cylinder, turbo-petrol engine with two electric motors, one on each axle. Combined outputs sit at a hefty 359kW and 675Nm, which comfortably out-muscles its key rivals.

Those figures do drop back to a more modest 110kW and 220Nm when running on the petrol engine alone.

Performance is strong for a large family SUV, with a claimed 0-100km/h sprint time of 4.9 seconds. You can toggle between pure EV and hybrid modes depending on the drive, which adds a layer of flexibility that suits short daily trips and longer highway runs.

There are two new petrol engines, two new badges and prices cuts of up to $10,000 right across the board for the line-up, along with additional standard equipment that improves the value equation even further.

The line kicks off with the 420, which can be had in either diesel or petrol guise. The 420i gains BMW's new B48 2.0-litre four-cylinder turbo petrol engine, which gains 5kW over the old motor to produce 135kW and 270Nm.

It also benefits from slightly improved fuel economy, with a drop of 0.3 litres per 100km for the Coupe and 0.5 for the Gran Coupe to 5.8L/100km, and a fall of 0.2L for the Convertible to 6.2L/100km.

The 420d retains its 140kW, 400Nm 2.0-litre four-cylinder turbo diesel engine, which returns 4.3L/100km in the fixed roof cars and 4.7L/100km for the Convertible.

The 430i – formerly known as the 428i – also receives the new 2.0-litre petrol engine, albeit in a 185kW/350Nm tune. Its fuel economy drops a healthy 0.6L for the Coupe and Gran Coupe and 0.4L for the Convertible, posting figures of 5.8 and 6.3L/100km respectively.

The top-spec 435i has been transformed into the 440i with the addition of BMW's new Twinpower 3.0-litre straight six petrol motor. Its output jumps 15kW to 240kW and by 50Nm to 450Nm, and its consumption falls by more than half a litre to 6.8 litres per 100km for the closed-roof pair and 7.2L/100km for the Convertible.

All cars come standard with a 'traditional' ZF eight-speed torque converter automatic transmission with steering wheel paddles as standard fitment, while a six-speed manual gearbox is a no-cost option across the line.

Charging is handled via a Type 2 CCS port, with support for up to 11kW on AC and up to 74kW on a DC fast charger. BYD claims a 30 to 80 per cent recharge can be done in as little as 20 minutes under ideal conditions.

The 35.6kWh lithium iron phosphate (LFP) battery is a standout, delivering a claimed electric-only driving range of 152km on the NEDC cycle. That figure is on the optimistic side compared to WLTP testing, but even with that in mind, it remains an impressive number for a plug-in hybrid of this size.

With a full battery, the combined fuel consumption is rated at just 1.0L/100km, translating to a theoretical driving range of over 1000km. Real-world results will vary depending on how often you’re able to charge and the type of driving you’re doing, but after a week that included a fair stretch of highway driving, my trip computer was showing 6.3L/100km. Overall, it’s a solid result, particularly for something with this level of performance.

Our brief test loop on a rainy, blustery Melbourne winter's day in all three model types (but no diesel) netted varying fuel consumption readings across the line; we recorded 8.4L/100km in a 420i sedan against a claimed figure of 5.8, 9.8L/100km for the 430i Gran Coupe against a claimed figure of 5.8L/100km, and 8.4L/100km against the 440i Gran Coupe's 6.8L/100km.

On-road performance is where things become a bit of a mixed bag. There’s no denying the Sealion 8 Premium is quick and it leans more heavily into its EV character than many large plug-in hybrids. It’s quiet in hybrid mode and responsive off the mark, which makes it easy to keep pace in traffic and overtake when needed. For something of its size, it also does a good job of masking its weight on the move.

Regenerative braking is offered in two levels, but even the stronger setting feels fairly mild. The upside is smoother low-speed driving, with none of the abruptness you sometimes get in hybrids, and it does still recover a decent amount of energy, particularly on longer descents.

Where it falls short is in its overall dynamics. The steering and suspension are tuned for comfort, which results in a soft, slightly floaty feel on the road. It’s not unpleasant and around town it actually suits the car’s brief, but there’s a noticeable lack of feedback and control if you’re expecting something more composed.

Visibility and driver positioning also take some getting used to. The forward view is decent, but the pillars are quite thick and it can be difficult to find a driving position that doesn’t feel a little enclosed.

Judging the edges of the car isn’t always intuitive, and while the 360-degree camera is clear, its perspective can feel slightly off. Objects tend to appear much farther away than they are, which isn’t the most reassuring combination when you’re trying to manoeuvre in tighter spaces.

BMW introduced a raft of tweaks to the 3 Series platform late last year, which have translated over to the 4 Series. The key addition across the line is BMW's two-stage adaptive dampers that feature a Sport and a Comfort circuit, fitted as part of the M Sport pack that comes standard on the 430 and 440, and is a $2600 option on the 420.

Larger 19-inch rims are fitted to the 430i and 440i cars, while the 420 gets 18s out of the box. It's possible to fit 18s on the more expensive cars, as part of the no-cost Luxury option pack that supplants the standard M Sport pack.

While our test was brief and held in less than ideal road conditions, the large-wheeled 4 Series really didn't enamour themselves to this author. There's a distinct lack of communication from the tyres and chassis through the steering wheel and your backside, while the combination of firm Sport shocks and large 19-inch wheels with narrow-section tyres made for an uncomfortable ride over country roads.

Sampling a 420i with the Luxury 18-inch rims, however, improved things immensely, with much better feedback and comfort that didn't come at the expense of handling.

One of BMW's strong points should be its steering, given all the 3 and 4 Series cars are still rear-wheel-drive… but it's not, unfortunately. The electrically assisted set up is far from perfectly calibrated, feeling too dull and digital underhand, no matter what the setting.

The pick of the bunch performance wise is – logically – the six-cylinder 440i. The turbo powerplant is potent from right down the rev range, with a muted yet still pleasing engine note permeating the cabin. The self-shifting mode on the eight-speed auto does a good job of keeping up as well.

The updated 2.0-litre four is a sprightly performer, too.

 six airbags, lane departure warning, pre-collision safety pack, parking sensors, active cruise control with collision warning, AEB and pedestrian warning, along with reversing camera and surround-view cameras across the line.

BYD offers the Sealion 8 with a six-year/150,000km warranty and an eight-year or up to 160,000km battery warranty. Both terms are competitive for its class.

Service is recommended every 12 months/20,000km with each workshop visit averaging a solid $596 for the first five years (year four is $1360). Accessing a BYD service centre is fairly easy as there are around 70 centres nationwide now.

BYD recommends premium unleaded petrol (95RON) to be used for the Sealion 8.

BMW offers a Service Inclusive program at the time of purchase, which for $1340 covers everything – including items like spark plugs, brake fluids and other fluids - for five years or 80,000 km scheduled. The cars are also covered by a three-year free roadside servicing program, in addition to BMW's two year, unlimited kilometre warranty.