Bentley Flying Spur vs BMW Alpina B4

What's the difference?

The Bentley Flying Spur Speed is a whole lot of car, for a whole lot of money. Sure, I’d rather have a Ferrari or a Porsche with similar power (and the Panamera shares the same V8 and hybrid set up), but then if you’re in the market for a Bentley like this you already have a garage full of other options. And I can see why you’d add one of these to your collection. Because you can.

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

You could almost call the B4 S the anti-M4. It's still fast and practical but from a completely different perspective. It's much more a grand tourer than the M4 and even with the Akrapovic exhaust (usually a byword for joyous, anti-social racket), subtle.

For some, the price won't matter because the Alpina delivers what they want - M4-like straight line performance without the histrionics or the uncompromising chassis. And there's also a bit of that perverse exclusivity of the styling that you won't get anywhere else.

Bentley seems to have spent the design budget on the Continental GT Speed, which was launched at the same time and gets the same new engine under its slightly sexier bonnet. The big move there has been going from Bentley’s traditional four headlight face to a smoother more modern one with just two lights, or eyes.

The Flying Spur, by comparison, sticks with the more traditional look, and four eyes, but that doesn’t necessarily mean it looks nerdier. Indeed, it’s still an impressive and handsome beast and does a mighty fine job of making this much metal and mass look bold and desirable. 

Truly, vehicles this large tend to look lumpen and making one look as good this Flying Spur Speed does is an impressive feat. Look at the photos and be impressed.

The interior fit out and fittings are stunning, with Bentley boldly claiming it makes the best car cabins in the world. It’s not an outrageous claim, either.

Alpina has always had a particular aesthetic that could uncharitably be termed as mid-'80s West German - all set square angles and body graphics. Think David Hasselhoff's Berlin Wall look. The company has never really deviated from adding squared-off body bits to the various BMWs it has rebadged under its long-running agreement.

For the B4S, Alpina adds the signature billion-spoke alloy wheels (only a slight exaggeration), a new front splitter complete with Alpina lettering, a weirdly proportioned boot lid lip spoiler and - not even joking - pinstripes. Like I said, mid-'80s West German. You can still recognise the sleek 4 Series Coupe but perhaps the worst of it is the super-sized, wonky-looking ALPINA B4S on the boot.

Inside is rather more restrained apart from the ill-fitting Alpina plaque under the climate control. Again, it's all 4 Series in here, with the lovely Merino leather liberally applied across the cabin. Less lovely is the wood on the door pulls and console but the door cards have an oddly appealing woven leather which looks and feels good.

Sadly the standard 4 Series steering wheel is along for the ride. There's nothing wrong with it - although the Alpina logo does look out of place - but if I were a product planner, I'd beg for the lovelier M wheel.

I’m not going to pretend that I had my laptop out taking notes while we were hitting 200km/h down the back straight at Magarigawa, but at more sane speeds there’s no doubt the rear seats of this car would be a very relaxing, plush, cosseting and pleasant smelling place to sit and work.

That’s at least partly what the Flying Spur Speed is for, a limousine for those who don’t like, or perhaps can’t quite afford, a Rolls-Royce, but still want great British solidity, class and that sense of obscene wealth, probably inherited.

The bonus of the Flying Spur is that it’s also a lovely place to be should you choose either of the front seats, with hugely comfortable seats that are more like couches, endless adjustability and many soothing massage settings for your heated and ventilated pews.

The spinning central 12.3-inch display remains the highlight, offering you a modern touch screen, which can disappear to reveal either three classic analogue dials or a plan piece of dashboard, if you prefer a “digital detox”.

If you're in the front, you're in luck - it's a comfortable place to be, with plenty of leg and headroom. Down back isn't terrible despite the coupe roofline. The two seats are nicely shaped for maximum comfort and separated by an odd plastic tray. The fold-down armrest has two cupholders.

Front seat passengers score a pair of cupholders (bring the total to four for the car) and the long doors will hold a bottle each.

The boot swallows a reasonable 445 litres, which isn't at all bad.

If you thought BMW don't mess about when pricing up its cars, you best strap yourself in. The 440i-based B4S starts at a solid $149,900. That's $48,000 more than the 440i and significantly more than an M4 Pure. But there's plenty of gear on offer and some genuine, bespoke Alpina additions.

Standard are 20-inch signature Alpina alloys, 16-speaker harmon kardon-branded stereo with DAB, super-soft Merino leather everywhere, dual-zone climate control, around-view cameras, reversing camera, sat nav, keyless entry and start, front and rear parking sensors, active cruise control, heated and electric front seats, head-up display, auto headlights and active LED headlights, LED taillights and electric sunroof.

The stereo and sat nav are run by BMW's iDrive. It's a cracker of a system and almost gets away without Apple CarPlay and Android Auto. The absence of such simple pleasures at this price point is a bit lame, but here we are.

If you’re going to put the word “Speed” in the title of your car, you really can’t mess about when it comes to the powerplant, and Bentley also has a proud history of making hugely powerful V12 engines to live up to. That’s a history that has now ended, with the announcement that the new 4.0-litre twin-turbo V8 in this Flying Spur Speed will be the one and only in all Bentleys, henceforth, including the Continental and the Bentayga SUV.

Bentley’s W12 engine is, sadly, no more, which might well make some older Flying Spurs quite collectable.

The V8 will come in different flavours, of course, and it’s also a hybrid, as is the modern way. Bentley calls the 140kW electric motor attached to the engine an “e-machine”.

Using that machine, the Speed can whisk you around in silent, EV-only mode for up to 81km. With such a stupendous sounding V8 on offer, it’s hard to see why you’d bother, but it’s an option, and the hybrid system is cleverly set up so that the harder you drive, the quicker the battery recharges, so effectively you’d almost never have to actually plug this PHEV in.

With the engine and e-machine combined, you’re looking at a staggering 575kW and 1000Nm, enough to propel all 2646kg of this Flying Spur Speed to 100km/h in just 3.5 seconds.

It might not sound quite as orchestrally moving as the big, sassy W12, but it’s still a hell of a replacement, as it is, in fact, “the most powerful Bentley engine ever”. That will do nicely.

A lot of your extra money turns up under the bonnet. These days the 440i packs BMW's slick B58 turbo straight six and the B4S does likewise. The boys from Buchloe in Bavaria (there are certain to be women there, too, I just liked the alliteration) added a pair of Alpina-spec turbos to generate a whopping 324kW and, more importantly, 660Nm. Alpina says 600Nm (the max torque figure of the brilliant M4 CS) is available from 2000-5000rpm, while the full 660Nm is available from 3000 to 4500rpm.

The M4 Pure has 317kW and 550Nm from the S55 straight-six. Just so you know.

Like the 440i but unlike the M4, the B4S employs the dependably brilliant eight-speed ZF automatic found throughout the BMW range.

So, if you were very careful to use your 81km of EV-only range, as often as possible, and you drove very slowly and treated the accelerator pedal with great care, you might, possibly, achieve the Flying Spur Speed’s claimed fuel-economy of 10.7 litres per 100km. 

That’s the great thing about hybrids like this, they are theoretical fuel misers of the highest order. But if you aren’t careful and you care more about enjoying that twin-turbo V8 engine you’ve paid so much money for, you’re never, ever going to get it under 15L/100km, and you’ll quite likely exceed 20L/100km, as we did, with ease, by driving it around a track all day.

Theoretically, again, this Bentley will emit just 33 grams of CO2 per kilometre. 

Alpina quotes 7.9L/100km on the combined cycle and we went through the premium unleaded at the rate of 11.7L/100km. I enjoyed myself, so that's not a terrible result.

Any car with a whopping 575kW and 1000Nm is going to be interesting, even invigorating to drive, but you’d have to say the smaller and lighter it is, the more excitement, and even fear, you’re going to be faced with.

In the case of the Bentley Flying Spur Speed, you’re talking about an enormous, and enormously luxurious and comfortable, sedan that’s designed to carry more than two people, and weighs a hefty 2646kg.

It’s a limousine powered by a rocket, as I said earlier, but looking at the size, and pondering the weight of it, you really don’t expect too much in the way of thrills. Effortless performance, sure, titanic overtaking thrust, perhaps, but then you read the fine print and note that this Flying Spur Speed can hit 100km/h in 3.5 seconds.

That’s seriously fast in anything, but in a car this big, and filled with as much luxury as a mid-sized super yacht, it feels other worldly. 

Hammering the big Speed around a tight, intense race track feels strange at first and then strangely comfortable. Even sitting in the back wasn’t so much frightening as amusing, as the big Bentley simply slopes through any challenge you throw at it.

Sure, I’d like it to be louder, and you do miss the sound of the old 12-cylinder engine (and Bentley fans in particularly might find its absence upsetting), but the V8 is still throaty enough to please your ears, and it’s important to consider that it’s actually more powerful than the old W12, which is no mean feat.

Compared to the shorter, sharper Continental GT Speed we drove on the same day, the Flying Spur does have a bit more body roll, a bit more pitch and dive under braking from 200km/h, or when accelerating ballistically out of slow corners, but it’s still stupendously impressive for what it is.

And that is a luxury limousine that can turn itself into a race track weapon if you, and your three passengers, want it to. 

One of the key differences between the B4 and M4 is the ride. While the M4 can crash over bumps and generally be a little hard to live with, the crew in Buchloe have gone after a much more plush ride. And in that they have succeeded because the B4 S is a mighty fine cruiser. Bumps are dismissed with a haughty disdain, even Sport + silliness doesn't completely write-off ride quality.

Very impressive too, is the steering. While still not at Lotus Elise levels of feel (few cars are), the Alpina tweaks connect the your palms to the road with more clarity than what you'll find in the 440i or M4. Where the M4 particularly adds too much weight, the 440i is a bit more circumspect in that regard.

And then we come to the engine. The B58 six is a belter, better even than the N55 that preceded it. It's still a 3.0-litre straight six but is part of BMW's modular engine family that starts with a 1.5-litre triple in the Mini and 1 Series. The Alpina-spec turbos are noisier, the Akrapovic exhaust lighter and also noisier. It doesn't have the all-out crackle and pop of an Audi or Merc (perish the thought), but when you're on it, the B4 means business. The 660Nm of torque, available over a wide rev range, delivers a steel fist wrapped in a velvet glove and bubble wrap - the speed builds rapidly but smoothly. 

The approach to the chassis tune seems to be based on the driving talents of mere mortals on normal roads, which is kind of like the 440i. It's terrific fun to drive hard but it's very forgiving and patient. The great thing about it is that you wouldn't think twice about jumping in it for the long haul, so comfortable and quiet is the cabin. The M4 will leave it for dead on a winding road, but that's perfectly fine.

One irritant is the replacement of the admittedly cheap BMW gearshift paddles with weirdly non-tactile buttons. They're not particularly easy to use and, probably worse for a sporty car, unsatisfying. It's an odd detail with which to go off the reservation. Cheeringly, the eight-speed ZF is its usual perfect self, so you don't have to worry too much about manual mode or go old school and use the shifter.

The Alpina ships with six airbags, ABS, stability and traction controls, ABS, stability and traction controls, forward collision warning, forward AEB, road sign recognition and active cruise control.

There are also two ISOFIX points in the rear. Neither the Alpina nor the 4 Series has an ANCAP safety rating.

The Bentley Continental GT Speed comes with a five-year, all-inclusive servicing plan as standard.

That sounds good, but stunningly, Bentley still only offers a three-year manufacturer warranty, albeit one with no mileage limitations. That's way below industry standard these days.

The battery that forms part of the hybrid system is, however, warrantied for eight years, or 160,000km.

Alpina offers a two-year/unlimited-kilometre warranty which is a bit behind the times and not in keeping with the price point. Servicing is another matter altogether and you're subject to your dealer's standard charges for servicing.