BMW 4 Series vs BMW 428i

What's the difference?

The BMW M440i xDrive Gran Coupe manages to combine sleek design with a fun-to-drive personality and surprising practicality. It’s a rapid premium, four-door, five-seater offering extra flair, and in this part of the market, good value. But more than anything else it’s got a cracking in-line six under the bonnet.

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.

So, how does this four-door 4 Series differ from a four-door 3 Series? The answer is as plain as the nose on this car’s face.

BMW’s head of design, Adrian van Hooydonk, has been expanding the brand’s signature ‘kidney grille’ in every conceivable direction, and this is the much talked about interpretation adorning all 4 Series models (petrol, hybrid and electric) as well as the M3 sedan.

The new Gran Coupe is longer, wider, and taller than the outgoing model, and the track is broader, front and rear. The wheelbase has also been extended, now a whole 5.0mm longer than the 3 Series.

The DRLs and headlight main beams are LED with laser high beams, immense gills square up the edges of the front clip, while a vent and the strake attached to it stand the car apart. Plus, of course, the doors are frameless. 

One niggle, though. I’m not in love with the slender door handles. It’s hard to get a good grip on them, especially in the wet. 

Standard 19-inch alloy rims are shod with Pirelli P Zero rubber 245/40 fr / 255/40 rr), the roofline slopes distinctly towards the rear, a lip spoiler on the trailing edge of the tailgate is classic BMW, darkened LED tail-lights wrap around the rear corner, and a diffuser-type panel is flanked by large exhaust apertures.

Our car’s ‘Aventurine Red’ finish is a $3850 option, but to my eyes anyway it looks superb.

Exterior trim including the grille frame, front air intake inserts, mirror upper housing, model designation badges, and tailpipe are finished in ‘Cerium Grey’, which I reckon 99.9 per cent of people will see as black. 

The interior will be familiar territory for any current BMW owner, the 12.3-inch digital instrument screen sitting in a compact, hooded binnacle, and partnering with a 10.25-inch multimedia display standing proud of the dash above the broad centre stack. 

The seats are trimmed in top-shelf leather with blue contrast stitching, plus the grippy sports wheel is also wrapped in genuine hide.

BMW calls the finish on the main buttons and controls ‘Galvanic’ which translates to a slick silver metallic look and feel. Configurable ambient interior lighting is a nice touch, and the broad console enhances the driver-focused feel, with a sprinkling of carbon-fibre around the centre console and dash lifting the sense of occasion.

Overall, the interior feels clean and classy with an obvious attention to detail.  

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.

At close to 4.8m long the 4 Series Gran Coupe is a sizeable machine. Up front, the feeling is airy and comfortable, and the rear is surprisingly spacious, especially in light of the car's sloping roofline.

At 183cm I have to fold myself tightly to fit under the low roof, but once inside I have enough room to sit behind the driver’s seat set for my position with more than enough legroom and adequate headroom. Put three full-size adults across the back row, though, and there will be breathing difficulties.

Kids will be fine, however, and individual vents with adjustable temp in the rear was a big plus during a particularly hot test week.

For storage there are generous door bins in the front with room for large bottles, a decent glove box, dual cupholders in the centre console, a reasonable lidded bin (which doubles as a centre armrest), and the wireless device charging bay (forward of the gearshift) makes a handy oddments space when not in use.

In the rear, again the doors feature pockets with room for (medium-size) bottles, there’s a fold down centre armrest with two cupholders, but thanks to the one-piece shells on our test car’s optional M Sport front seats there are no map pockets.

Power and connectivity runs to a USB-A socket and a 12V outlet in the front centre console, as well a USB-C port in the front storage bin, a pair of USB-Cs in the rear, and a 12V outlet in the boot.

Speaking of which, lift the tailgate and with the rear seat upright we were able to fit all three of our suitcases or the beefy CarsGuide pram into the healthy 470-litre (VDA) boot space.

Lower the 40/20/40 split-folding rear seat down and 1290 litres of volume is at your disposal. Plus there are handy bag hooks and tie-down anchors to help secure loose loads.

You can also tow a braked trailer up to 1.8 tonnes (750kg unbraked), but don’t bother looking for a spare of any description, a repair/inflator kit is your only option.

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.

Under the bonnet is BMW’s (B58) all-alloy 3.0-litre twin-scroll turbo intercooled, in-line six-cylinder engine, driving all four wheels via an eight-speed automatic transmission and electronically controlled clutch pack, as well as an electronic limited-slip differential at the rear.

It features high-pressure direct-injection and BMW’s ‘Valvetronic’ system managing air flow to the intake side, to produce 285kW at a relatively high 5800-6500rpm. But the big punch is 500Nm of peak torque from just 1900rpm all the way to 5000rpm.

The M440i is also a mild-hybrid with a 48-volt starter motor-generator and supplementary battery able to give an 8.0kW kick at low engine speeds.

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.

BMW’s official fuel economy figure for the M440i xDrive Gran Coupe, on the ADR 81/02 - urban, extra-urban cycle, is 8.2L/100km, the 3.0-litre turbo six-cylinder emitting 187g/km of C02 in the process.

Stop/start is standard, and we saw an average of 11.1L/100km over city, B-road and freeway running during a week with the car.

With the 59-litre tank brimmed (with minimum 95RON premium unleaded) that real-world test number translates to a range of around 530km.  

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.

BMW says the M440i xDrive Gran Coupe will accelerate from 0-100km/h in 4.7sec, and I reckon the threshold for a properly quick car is sub-five seconds.

The 3.0-litre turbo six develops its peak power of 285kW between a relatively lofty 5800-6500rpm, but the big number is a solid 500Nm punch of pulling power delivered between 1900-5000rpm.

Squeeze the throttle pedal pretty much anywhere in the rev range and the response is glorious. Rapid acceleration accompanied by raucous engine noise and rorty exhaust note (albeit with some synthetic support). Various pops and bangs in the Sport settings add extra entertainment.. 

The eight-speed auto gets some electric support from the mild-hybrid system to fill the torque gap on up shifts, and the result is a conventional torque-converter transmission that behaves like a dual-clutch.

Shifts are seamless in general driving, and satisfyingly quick in a more aggressive mode, the wheel-mounted paddles dialing up the fun in manual changes. 

Suspension is double wishbone front and multi-link rear with the standard ‘Adaptive M Suspension’ built around an adaptive damper set-up.

The change between the ‘Comfort’ setting to the ‘Sport’ or ‘Sport+’ calibration is close to instant and makes a discernible difference, especially in terms of ride comfort.

I found the best ‘Individual Sport’ arrangement to be damping in Comfort, with the steering engine and transmission in Sport. The car flows so beautifully through corners with urgent response from the powertrain.

By all means dial up the suspension if you’re having a real crack, but the car feels superbly balanced, stable and predictable in Comfort (front to rear weight distribution is 50:50).

The electrically-assisted variable-ratio steering is nicely weighted with good road feel, and the grippy sports steering wheel is a nice point of contact.

The xDrive AWD system’s default setting is rear-biased, although it will push most of the drive forward when required. But the RWD feel is unmistakable. 

The M440i weighs in at around 1.9 tonnes but feels lighter and more nimble than that figure would typically indicate.  

A standard electronically-controlled M Sport limited-slip differential puts the power down confidently. I have a favourite LSD test corner on my regular evaluation drive, a sharply twisting and rising left-hander.

Rolling into it in a low gear before planting the throttle mid-corner, the car simply hunkers down without a hint of fuss (or traction loss) as it rockets out the other side.

Optional M Sport front seats ($2000) provide comfort and firm location in equal measure and in terms of ergonomics BMW knows how to focus on the driver and set-up an efficient environment. Key controls are perfectly positioned and simple to operate.

I have an issue with the ‘Lane Departure Warning’ function, however, which is too quick to intervene and overly intrusive when it does so. I turned the ‘Steering Intervention’ function off. You can dial down steering wheel vibration warnings, too.

The standard M Sport brakes feature big vented rotors front and rear, with fixed four-piston front calipers doing the bulk of the work. They’re strong but don’t bite or release too aggressively. It’s easy to grease in a smooth application. 

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.

The M440i Gran Coupe is covered by BMW’s three-year/unlimited km warranty (including paintwork), as well as 12-year/unlimited km anti-corrosion (perforation) cover. 

That’s off the premium market pace now with Genesis, Jaguar, and Mercedes-Benz at five years/unlimited km and Lexus set to join them from January 1st, 2022. 

That said, roadside assistance is provided for the duration of the main warranty, but it’s worth noting “rattles and squeaks” are only covered for one year.

Service is condition-based, the car telling you when maintenance is required, and a range of service packages are available. The basic plan covering a 4 Series for five years/80,000km comes in at $1750. 

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.