BMW's 420d costs almost the same as a top-spec 330d saloon - but which is the better car?
The 4-series has good body control, but the 3-series is more fun to drive
The driving position in the 420d is lower, and its cabin feels more premium
The 330d comes with more equipment and more room in the rear
As tested here in M Sport specification, this 330d costs £38,605
Despite being slightly shorter than the 4-series, it's the 3-series which offers the most space in the rear
Our 330d came on 19-inch alloy wheels
Both models sport BMW's signature kidney grille
The 3-series' boot is slightly wider and deeper than the 4-series
Boot capacity is the same on both models, at 480 litres
Like the 330d, our 420d test car came on 19-inch alloy wheels
The 4-series is the better car to look at, in our opinion
Despite its classy cabin, the 4-series doesn't feel as engaging to drive as the 3-series
The 4-series' 4-cylinder 2.0-litre turbodiesel engine produces 181bhp
The 330'd 6-cylinder 3.0-litre turbodiesel engine produces 255bhp
In xDrive M Sport specification this 420d Gran Coupé costs £37,975
The 420d can reach 62mph in 7.5 seconds
The 330d is faster to 62mph, taking 5.3 seconds
The 330d also has a higher top speed than the 420d, at 155mph
Both cars come with a 57-litre fuel tank, but the 420d will travel further
The 420d returns 56.5mpg on a combined cycle, slightly better than the 330d's 54.3mpg
For power delivery, pace and refinement the 330d has the edge
Now must be a curious time to be selling BMWs if, as rumours suggest, the popularity of the evergreen BMW 3-series is suddenly under threat. Time will tell if that’s true, but it’s certainly what Autocar’s sources are beginning to hint at.
There’s no need for alarm bells, because the bedrock of a 50,000-unit sales phenomenon doesn’t just vanish overnight. But at certain points in the model range, the cracks are starting to appear. Higher-end Threes are evidently getting harder to sell.
A close friend of mine recently changed jobs, opted out of the new company car scheme, and went to his local BMW dealer to investigate financing his own new car. He wasn’t sure what he wanted, but fell quickly under the spell of the new four-door 4-series Gran Coupé.
He isn’t alone in that. A big proportion of 3-series owners due for a new car this year are currently on the waiting list for a 4-series, they told him. “Everyone wants one,” they said.
When our man sat down to talk turkey, BMW’s ‘product genius’ advised that he’d be waiting several months for delivery and, with interest in the car running so hot, he’d also be paying close to full price. So far, so rubbish the sales pitch.
But it didn’t end there. “If you’re not absolutely decided on a 420d, perhaps there’s something we can do to tempt you back towards a 3-series saloon,” the salesman said. ‘Something’ consisted of a £6000 manufacturer-funded deposit contribution on a 330d bought on finance, plus another £3000 off from the dealer – making the monthly payment on the six-cylinder BMW £40 less than he’d pay for a four-cylinder 420d Gran Coupé. Crikey, thought I, £9k off a five-star car is a very good advert indeed for taking delivery of a new BMW in September.
My friend, meanwhile, was in a right old pickle: wait for the newer, prettier 4-series and put up with the four-cylinder diesel engine – or get a new six-pot 3-series saloon in half the time, with more performance and more standard equipment, for less money a month? It was grunt versus grace, and desirability versus the discount.
His monthly saving would probably be more than offset against greater insurance and fuel costs for the 330d – but which car would give him the bigger buzz?
Being something of a brick, I volunteered to find out, imagining that this would be a straightforward choice, on behalf of a fairly low-mileage private buyer, of either 255bhp or 181bhp. Easy peasy. But with the two cars side by side in a Wiltshire car park, the complexity of the decision fully reveals itself.
This new 4-series is a handsome thing. It makes the 3-series look unexpectedly dumpy and awkward – all straight-sided from the rear end and ill-proportioned in profile.
The frameless doors, elegant roofline and eye-catching details of the 4-series all contribute to a much more appealing overall impression than the 3-series gives. Which is saying something considering that, to these eyes, a 3-series is still about the best-looking ‘normal’ compact exec you can buy.
On the inside, the cars are much less easily separated. To be frank, the 4-series’ cabin designers ought to have done more. The architecture, material richness and finish of both fascias are identical. You sit slightly lower in the 4-series and feel a touch more intimately cocooned by the nearer driver’s window and roofline, so the 4-series feels a bit more special, but not much.
In the back, the relative shortage of passenger space in the 420d is big enough to notice. And although the 4-series’ boot is easier to access, it’s slightly narrower and shorter than that of the 3-series.
It’s not often that a road tester gets handed two cars as precisely matched as these to compare. Then again, all-BMW twin tests aren’t normally as interesting as those involving other brands as well. This one’s certainly not short of intrigue or subtlety, though.
BMW supplied our pair with matching xDrive four-wheel-drive sport automatic transmissions and similar adaptively damped M Sport suspension set-ups, in similar M Sport trims – even with identical alloy wheel sizes and tyres. And yet they are more different to drive than the gap between their respective engines and performance levels would suggest. And that, in itself, is a pretty big gap.
There are, of course, fundamental differences between a 3-series and a 4-series that account for some of the disparity between their driving experiences. Lower and wider of both body and axle tracks, the 4-series has its own chassis tuning, intended to convince you that it’s more spry and precise than its cheaper sibling. It works.
The Gran Coupé feels a shade more taut in its body control and crisp in its directional responses than the saloon. Although outright grip levels are as evenly matched as you’d expect and both cars have excellent cornering balance, the 4-series is just a little bit more eager and direct as you turn the steering wheel.
The 330d hits back because its surfeit of power and torque makes it more engaging once you’re settled in a corner, driving out. Simply put, a 420d doesn’t have the urge to feel characteristically rear driven when you want to have a bit of fun. A 330d does. Even in xDrive form, it’ll wiggle its rear end and take a poised, neutral attitude out of a bend under power.
In that microcosm, you could say that the 330d handles like a fully fledged BMW and the 420d doesn’t – although it’d be harsh on the 4-series to apply that generalisation more widely.
On steering feel, for example, the 4-series’ helm feels a tiny bit more fluent and connected at bumbling speeds, but both systems come alive as you load them with cornering forces, and both telegraph ebbing grip well enough.
Working against the 4-series is an occasionally nagging ride. On smooth A-roads and motorways, the 420d’s chassis flows between gentler dips and bumps well, but on B-roads it’s too firm. Even in Comfort mode on the adaptive suspension, it feels short on wheel travel and slightly aggressively damped.
The coarseness of the 420d’s engine, its relative lack of potency and that patchy ride contrast starkly with the 330d in all departments. It may not be that the 3-series’ 3.0-litre straight six is markedly quieter than the 420d’s four-pot, but it seems that way because it’s so much more smooth and suave.
On power delivery, the 330d is so much more flexible, as well as stronger absolutely everywhere, than the 420d. The 330d is every inch a distinguished premium product. And it’s a much more rounded, luxurious machine than the 4-series as well, thanks to a chassis that can be supple and forgiving at one moment and still stout and engaging the next.
So in the end, it is a straightforward choice: for me, for my mate, and for anyone smart enough to value true class over novelty value.
The 330d remains not just the very best BMW in the real world, but also one of the most complete new cars that money can buy. A 25 per cent discount on one is sale of the century stuff – and if you can get one, regardless of which other BMW the crowds may be queuing for at the time, you shouldn’t need asking twice.
BMW 330d xDrive M Sport auto
Price £38,605; 0-62mph 5.3sec; Top speed 155mph; Economy 54.3mpg; CO2 137g/km; Kerb weight 1685kg; Engine 6 cyls in line, 2993cc, turbodiesel; Power 255bhp at 4000rpm; Torque 413lb ft at 1500-3000rpm; Gearbox 8-speed automatic
BMW 420d Gran Coupe xDrive M Sport auto
Price £37,975; 0-62mph 7.5sec; Top speed 142mph; Economy 56.5mpg; CO2 131g/km; Kerb weight 1675kg; Engine 4 cyls in line, 1995cc, turbodiesel; Power 181bhp at 4000rpm; Torque 280lb ft at 1500-3000rpm; Gearbox 8-speed automatic
Get the latest car news, reviews and galleries from Autocar direct to your inbox every week. Enter your email address below: