BMW 428i vs BYD Sealion 8

What's the difference?

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.

There’s quite a bit to like here. There’s plenty of equipment, and lots of choice in price, trim level and mechanical complexity.

The driving dynamics are fine if you’re not looking for anything sporty although the performance offered by the dual-motor variants must be considered excessive, even if it’s pretty exciting the first time.

Perhaps what’s missing from the Sealion 8 experience is anything that stamps the car as something special within its hotly-contested market segment. Which is another way of saying it offers up the same limitations, most notably in the third row accommodation and access.

You only need to drive a one-box people mover and utilise the rearmost seat, to understand that the two-box SUV, while a pretty marketable thing, is compromised once the passenger count exceeds five. Nothing new there, but nothing new in the BYD, either, to change that narrative.

At which point, the front-wheel drive variant emerges as the most pragmatic choice and probably the one that meets all the important family tasks headed its way for the smallest outlay.

Note: CarsGuide attended this event as a guest of the manufacturer, with meals provided.

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.

BYD has done its best to give the Sealion 8 its own character and vibe. In fact, it’s a pretty smart looking thing - although still very much a two-box wagon concept - and that’s no given when you consider how much some big SUVs can start to look like large blobs of nothing when you look closely.

There’s the usual Darth Vader stuff at the front, but in profile, the diagonal vent across the front door makes a bit of a statement. The 'plaited' motif of the tail-lights might be stretching things a bit, though.

Inside, the modern board-room feel is invoked by the angular lines and high-tech look and feel of the large info-screens. The panoramic sunroof of the Premium grade also helps brighten up an otherwise pretty dark space.

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.

BYD has made sure all three rows of the Sealion 8 are fit for purpose while attempting to make the rearmost row (traditionally the trickiest to get right) less of a downmarket place to be. With that in mind, both rear rows get air vents and climate-control adjustment for that part of the car. There's also a pair of USB-C charge ports in the second row and a single USB-C and USB-A port in the third row. The third row also has cupholders bult into the wheel arch on each side.

With the third row in place, there’s a decent amount of luggage space (270 litres) largely thanks to the Sealion’s five-metre overall length. There’s no spare tyre, but a puncture repair kit lives under the floor (as does the removable cargo blind) and the rearmost luggage space also incorporates a 12-volt socket and luggage hooks.

A pair of pull-tabs drop the headrests and then the entire split third row in a single movement, at which point you suddenly have a five-seater with a huge, 960 litres of luggage space. And if you need to cart gear over people, the second row also folds flat to open up 1960 litres of space.

Up front, the feeling of spaciousness is amplified due to the low scuttle height and what the aviation industry calls the glass cockpit (no analogue dials or gauges at all). The 15.6-inch central info-screen runs the usual apps and control displays but, thankfully, the climate control touch-controls are tethered to the bottom of the screen, so they’re always visible regardless of what else is going on.

The 10.2-inch driver’s display adds a head-up function in Premium trim and displays the usual array of information required to operate the vehicle. But even better is the steering wheel which features a thick, well-padded rim that looks and feels pretty luxe. It also houses the usual buttons for stereo, phone and cruise-control functions.

A really nice touch is the addition of an extra set of tilt controls on the inside of the passenger’s front seat, allowing the driver to control that seat to allow people in or out without leaving their own seat. Nice one.

It is, of course, the centre row of seats that will make or break a car like this for many families. Even though many clans will not use the rearmost seat much of the time, the central row will get a huge workout. So it’s nice to see that leg, foot and headroom are all sufficient for even growing teenagers. Again, the car’s overall length appears to be the key, but it’s also worth noting the centre row seat is comfy and supportive. The outboard positions in the second row also feature heating and ventilation functions.

The third row, however, follows SUV tradition by being strictly for smaller kids. Access past those huge wheel arches is tight, and once you’re in, there’s a combination of dark trim and tiny windows to limit joy.

While it won’t matter to many buyers, the front-drive Sealion 8 is rated to tow 1800kg with a braked trailer, and up to two tonnes in the all-wheel drive version. But there’s no spare tyre fitted, and roadside flats need to be addressed by the included tyre repair kit.

BYD will offer the Sealion 8 in three trim levels, starting with the front-drive Dynamic at $56,990, before on-road costs, then moving to a pair of all-wheel-drive variants, the first with the same Dynamic trim level at $63,990 and the range-topping Premium AWD at $70,990.

The Dynamic trim level on both the front-wheel drive and the all-wheel drive variant gets you three-zone climate-control, air vents in both rear rows, full connectivity including wireless Apple CarPlay and Android Auto. There’s also wireless phone charging. The Dynamic specification also takes on 20-inch alloy wheels and there’s full LED lighting as standard.

Pony up for the Premium trim and you make the switch to 21-inch alloys, a 21-speaker sound system and even a massage function for the first two rows of seats. The Premium also includes a head-up display for the driver.

Not as easy to quantify is the level of plush inside the cabin. There are lots of soft-touch surfaces and the whole interior design looks pretty fresh and modern and well put together. But more than that, there’s a bit of design flair that makes the BYD feel perhaps a bit more expensive than it really is. That’s not an easy thing to pull off. But it seems to work here, even in the entry-level Dynamic trim.

Against the competition, the Sealion 8 can't match the similarly specified Chery Tiggo 8 on price, even though on performance and EV range, the Tiggo 8 and the entry-level Sealion 8 are quite similar. The more expensive Sealion 8 Premium, meanwhile, lines up pretty neatly on price with the Kia Sorento S PHEV. But that vehicle can't get close to the epic straight-line performance of the BYD.

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.

BYD has managed to keep a lid on the price of the entry-level version of the Sealion 8, by specifying it with front-wheel drive rather than the all-wheel drive of the other two variants. It still gets the same driveline beyond the lack of a driven rear axle, although battery capacity is the other difference.

As such, you’re looking at a 1.5-litre petrol engine (kind of the default powerplant for Chinese SUVs right now) with a turbocharger. With the 19kWh battery chiming in to power the electric motor, the driveline can achieve outputs of 205kW and 315Nm.

In the case of the AWD variants, the larger 35.6kWh battery and extra electric motor ups the potential outputs to 359kW and 675Nm which is a huge jump any way you look at it and gives the Sealion 8 a huge bandwidth when it comes to matching buyer performance aspirations.

All the variants have the potential for a claimed electric-only range of greater than 100km if owners use the plug-in facility to charge either at home or at work. For the AWD variants, the larger battery stretches the EV range to a claimed 152km. On longer journeys or whenever the battery has reached about 25 per cent capacity, the Sealion 8 acts just as any other hybrid with regenerative braking and electric assistance to aid performance.

In suspension terms, the BYD is pretty conventional but if you do pay the extra for the Premium variant, you’ll gain adaptive dampers.

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.

BYD claims a range of more than 1000km for both variants of the Sealion 8, provided you start with a fully charged battery and a full 60-litre fuel tank.

The BYD can also make use of commercial fast-chargers and, when using the maximum 40kW on the FWD version and the 74kW possible for the AWD variant, the charging times from 30 to 80 per cent are both under 20 minutes. The Sealion 8 can also charge at 11kW on an AC socket and the vehicle also offers V2L (Vehicle to Load) capability, meaning it can power on-site work tools, camping gear or even your house at night.

Provided the EV battery is kept at 25 per cent capacity or above, BYD claims a 1.0-litre per 100km fuel consumption figure for the car based on the laboratory test. In the real world, the results will vary enormously depending on where you drive and how the car is used. Deplete the battery and continue to drive at highway speeds, and your actual fuel consumption might easily increase to many times that 1.0-litre claimed figure.

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.

The first thing you’re going to do in a Sealion 8 is wonder where the gearshift is. It’s a column-shift, but it's not only located where a traditional indicator stalk would be, it looks very much like one, too.

This promises two things. One, you’ll spend a few seconds finding it and two, you’ll try to turn the indicators on with it at least once every drive. (The real indicators are on the other side of the steering column.)

Another note to those test driving a Sealion 8. Sample the front-drive version first. (I’ll get to why in a minute.) When you do, you’ll soon figure out this is a driveline that prioritises electric running. That is, the petrol motor barely ever actually drives the wheels (only at full throttle and higher speeds). Any other time, if the petrol engine is running, it’s to charge the battery that keeps the electric motor purring away. This is how efficiency is defined by BYD.

You’ll also find that the Sealion’s acceleration is purposeful in that electric-motor way, but hardly startling. And when you do smash the throttle and force the petrol engine to drive the axle, you’ll notice that this takes a fair time to play out, and that when everything is grunting as hard as possible, the petrol engine is quite noisy and even a little harsh sounding. Use the driveline sensibly, though, and it’s all smooth and quiet, even if that then means you can hear a little suspension noise creeping into the cabin.

That done, you’re now free to drive the AWD variant. Why wait? Because this thing is seriously off the leash. Bear in mind that 359kW of power is getting on for the thick end of 500 horsepower in the old money, so even though the Sealion 8 is a hefty critter at about 2.5 tonnes, all that power and torque will get it from rest in under five seconds, or thereabouts. The relevance of this to family-car technology is hugely debatable, but it’s one heck of a party trick the first time you try it.

The huge torque also magnifies the Sealion 8’s natural tendency to lift its inside front wheel when accelerating out of a turn. A small tyre squeak can sometimes be heard before the traction control gathers it all together, but even the single-motor variant displays the same trait.

In steering and suspension terms, it’s probably fair to say the Sealion 8 doesn’t unlock any new depths of talent. The ride is pretty comfy but at the expense of body control and the steering points the wheels but doesn’t convey much else to the driver.

That said, the fact everything seems to be tuned to the same frequency means it all works okay. You don’t have too-fast steering fighting the tyres or too firm suspension upsetting the interior calm. Use it as a family would, and it’s 100 per cent fit for purpose.

Any family car needs to be safe, so BYD has thrown the kitchen sink at the Sealion 8 in terms of its active and passive safety gear. That starts with nine air-bags including full-length curtain side bags and a centre-front airbag to help prevent head clashes.

There’s also a 360-degree camera on all grades, front and rear parking sensors, and the full line-up of current driver-assistance functions including autonomous emergency braking, lane-keeping assistant, rear-cross-traffic alert and assistance, blind-spot monitoring, driver attention monitoring and a tyre-pressure monitoring system.

To that lot, you can add adaptive cruise-control, traffic-sign recognition, adaptive headlights, front and rear collision warning, anti roll-over systems and hill-hold functions. It’s also worth mentioning that the overhead camera system is very, very good with a clear, crisp display and no processing delay.

The driver-attention monitoring seems to behave itself better than some of the over-active systems other makers specify, but the lane-keeping assistance function is still far form perfect. To be fair, it is less aggressive than some such systems and the intervention is more subtle, but the recued aggression seems to be packaged with lower sensitivity. As in, the cameras seem to sometimes miss a critical white line, particularly if its faded or less than freshly painted.

There are also ISOFIX child restraint tether points in both the second and third rows, as well as seat-belt warnings for every position and an electronic child-safety switch for the doors.

The Sealion 8 is yet to be crash tested locally, so no ANCAP star rating is available.

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.

Servicing any hybrid can be a bit more expensive thanks to the presence of two propulsion forms.

In any case, the Sealion 8 requires routine servicing every 12 months or 20,000km.

Warranty is BYD’s normal six-year/150,000km cover, although there’s also eight years and 160,000km of cover for the EV battery.

BYD also claims its 'Blade' battery technology is among the safest in the business, and says the design resists damage (and, therefore, the risk of fire) better than the competition.