Alpina B5 review

Of course, and weird though it seems to write it, the B5 is not the only 600bhp mid-size exec out there: Audi and Mercedes have them, too. But it is only BMW who won’t be offering an estate version of its new M5, Munich having again decided that non-existent US sales for cars in this format make its development pointless.

But Alpina makes fewer than one car for every 1000 built by BMW, so this always has been and remains an opportunity. Indeed, Bovensiepen says most B5s sold will carry Touring bodywork.

As for standard equipment, expect to find a well-stocked 5 Series with adaptive LED headlights, cruise control, quad-zone climate control, electrically adjustable and heated front seats, a Nappa leather upholstery, reversing camera, and BMW’s iDrive infotainment system complete with a 10.25in touchscreen display, sat nav, and BMW’s connected services, fitted as standard. The B5 is finished off with some Alpina tinkering, including tweaks to the sports suspension, auto gearbox, driving modes and steering. A new styled rear spoiler and valance, 20in alloys, ceramic finished controls, floor mats, and the customary blue instrument cluster.

Powering the Alpina B5 forward

The start point, clearly, is BMW’s superb new 5 Series but powered by the 4.4-litre twin-turbo V8 currently found in its 750i big sister. The main focus of the modifications to it has been the fitment of bigger, twin-scroll turbos boosting at a muscular 1.4 bar. This is enough to raise power from a fairly lazy 444bhp to a very active 600bhp and torque from 479lb ft to 589lb ft. Alpina will also be completing the 5 Series range with the D5 S, which is powered by a 3.0-litre, straight six diesel, producing 321bhp and 516lb ft of peak twist capable of reaching 171mph and achieving over 40mpg.

The ZF transmission gets strengthened gear clusters and additional cooling, plus quicker shifts and a larger torque converter. Alpina says it can swap a cog in 0.1sec, which is rapid by any standards in the world.

Keeping the B5’s feet on the ground

The real attention, however, has gone into the suspension. Chassis development chief Andreas Vollmer talks of all the days, weeks and months he and his team spend not hurling themselves around race tracks but just driving, using the cars as customers would. And then they change everything.

You’d expect new springs, dampers and roll bars for a car such as this, but the geometry is different, too, and none more so than at the front, where there’s an entire degree of negative camber that requires completely different wishbones in order to achieve it.

At this stage, though, they’re only getting into their stride. The car has BMW’s four-wheel steering system, but specifically tuned by Alpina, and the software for the normal electric steering is completely rewritten. They even fit a different steering wheel because they don’t like the squidgy rims found on BMW M cars any more than I do.

Four-wheel drive is fitted here for the first time in seven generations of Alpina 5 Series, but Bovensiepen rejects the suggestion that he had no choice in this.

“We could have had a rear-drive B5 and I’d have preferred it, but even I accept that with 589lb ft, the customer wants four-wheel drive,” he says.

So they fiddled with that, too, and now the B5 sends more of its torque (up to 90 percent) to the rear wheels and does so more of the time.

Interestingly, despite the all-wheel drive hardware adding 70kg, the entire car is 30kg lighter than the previous, rear-drive B5. And Alpina has broken with years of Michelin-shod tradition and developed a new Pirelli tyre to go with the car.

Unleashing the B5’s power on the track

The irony is that although this car was principally developed on the road, it can only be driven on the track – for now.

As I write, Alpina has just three production-specification B5s and none is yet homologated for road use. So it is around the Bilster-Berg test track, smack in the middle of Germany, that I make my acquaintance.

And the fact that it doesn’t just give up at the first corner is remarkable. This is a deliciously evil track, undulating, very fast and perfect for light, track-tuned cars laden with downforce, such as the Porsche 911 GT3 RS I drove there, and not at all for softly sprung 2150kg estates.

The engine sounds superb and completely natural – although a slightly embarrassed-looking Bovensiepen confesses it’s the first Alpina to synthesise just a tiny bit of sound through the loudspeakers – and is completely simpatico with its new gearshift strategy.