BMW Alpina B5 (2011) CAR review

BMW Alpina has produced its latest B5 Biturbo, based on the F10 5-series. Now that BMW is moving to twin-turbo V8 power for the next M5, has BMW Alpina stolen a march on its factory rivals at BMW M? Or is the BMW Alpina B5 Biturbo unlikely to threaten the default fast BMW saloon? 

Read on for our first drive review of the BMW Alpina B5 Biturbo…

Go on then. So has BMW Alpina stolen a march on the next M5?

Any comedian will tell you that it’s a sign of either arch-confidence or morbid complacency to send on stage a warm-up act who’s funnier than you. The forgotten comic I saw headlining at London’s Meccano Club back in the '90s was supported by a young Alan Davies and an unknown trainee doctor called Harry Hill. History has done the rest.

Let’s hope the new BMW M5 is reading this, because it’s not due on stage until 2011 at the Frankfurt motor show, yet right now its audience is being warmed up by a simply brilliant understudy wearing an identical suit: the Alpina B5 Biturbo.

Is the BMW Alpina B5 really the same basic car as the upcoming M5?

As you know, Alpina is a unique outfit, a purveyor of fabulously exclusive BMW-based epics which somehow combine total faithfulness to the original with a level of bespokeness so rich the company is classed as a car manufacturer in its own right. That's what received wisdom says, anyway.

The engineering differences between Alpina models and the BMWs that spawn them are usually fairly overt – Alpina favours turbocharging and auto gearboxes, while BMW M has made its name on natural aspiration and bone-shaking ride.

But the M5 will be the first M saloon to pack a turbo – two turbos, to be precise – and thus its 4.4-litre V8 will be exactly the same as the engine in the B5. The twain shall meet. This should be interesting.

What has Alpina done to the twin-turbo V8 engine in the B5?

The engine itself is tuned to produce 500bhp, leaving the B5 somewhat shy of the M5’s likely 578bhp, but it’s hard to imagine needing more power than this. The car is deeply, devastatingly quick, particularly so when it mines its vast torque reserves (516lb ft) in the mid-range.

Urged on by the ZF-designed eight-speed auto 'box, you fire through the cogs like a machine gun minus the kick, at no time doubting the claimed 4.7sec 0-62mph benchmark. Frankly, it feels faster than that. And 191mph is not just believable, it’s inevitable.

Does the B5 driving experience suffer due to the automatic transmission?

The gearbox is truly a work of art, using a unique single-cylinder step-down to retard fuel injection into a given cylinder for a split second, thus allowing the box to handle this much torque. In manual mode it’s even better, because they’ve replaced the paddles with two tactile aluminium buttons on the back of the wheel, and you can use them freely to skip gears on the downshift. Playtime!

How does the BMW Alpina B5 ride and handle?

The headline act is the ride. Alpina has chucked out the hateful runflats, retuned BMW’s adaptive dampers and dropped the whole rig closer to the road, creating unrecognisable refinement while maintaining the 5-series gift for body control.

They’ve got the steering right, too – improving the 5-series set-up for more meat at speed and less heft when parking – presumably sending flustered BMW helm boffins scuttling back to their computers.

Sounds like the B5 is nigh-on perfect, then?

Not quite. There’s an unavoidable feeling that the 530d can do virtually everything for a fraction of the B5’s £70k, and although the diesel is slower, the B5 has played all its best cards before you get to high-speed handling.

At the limit, all-round smoothness isn’t the personality you really want, no matter how deliciously rare. No, you want uncompromised talent and bad-mannered arrogance. You want the M5.