Alpina B3 review

Understanding the B3's mechanical changes

We hold the B3 in high regard at Autocar. The old model, known as BMW’s other M3 around these parts, wasn’t far off scoring a full five stars in our road test, when we described it as “rapid, rewarding but undemanding”. Can this new one deliver in the same way? We’ve got a circuit and an extended route on German country roads to find out.

Subtlety has traditionally differentiated Alpina models from their BMW cousins – and that holds true here. The new B3 updates the latest 3 Series design nicely, taking on a determined yet unobtrusive appearance that is highlighted by a unique front bumper extension, Alpina’s signature multi-spoke aluminium wheels, a bootlid spoiler and four round chromed tailpipes within a reworked valance to the rear bumper.

In combination with a moderate reduction in ride height over a standard 3 Series, the changes help to set it apart from the crowd. On the inside, there are unique trims and upholstery. A neat touch is the Alpina-specific digital instruments with the firm’s signature green hue featuring prominently within the speedo and rev counter.

The new B3’s twin-turbocharged 3.0-litre petrol engine is based heavily on BMW M’s newly introduced S58 unit – the same inline six-cylinder that powers the new M3 and M4. It’s the first time Alpina has opted for an engine from M division rather than one from BMW’s standard line-up. Such are the changes, though, that it adopts a thoroughly different character.

The biggest departure is the adoption of new turbochargers. Developed by Alpina, they retain the same turbocharger housings as the new M3’s but run bespoke internals, including flow-optimised low-inertia turbine wheels to boost induction, along with other measures, including a redesigned air intake, new cooling system, Bosch DME8.6 S ECU and an Alpina-specific stainless steel exhaust system that features its own unique particulate filter.

With 462bhp and 516lb ft, the new longitudinally mounted unit has 29bhp and 29lb ft more than the N55-based Alpina engine in the most powerful old B3 model, the B3 S. By comparison, the standard version of the new M3 has 473bhp and 443lb ft.

How does the B3 perform?

On the right road, the B3 is stunningly quick. It is quite a different experience to drive from the new M3, though. Deliberately so. Whereas the new M car relies primarily on revs to form its performance, the latest B3 sticks to Alpina’s long tradition of endowing its road cars with a mountain of usable torque – and the result on a heavily pegged throttle, both off the line and through the gears, is nothing short of stunning.

It might lack the acoustic voracity of the M3 but the accelerative ability of the B3 is beyond question. The B3’s smaller turbos not only help to plump out the torque curve but they also give the new engine outstanding manners. It responds crisply to throttle inputs and accepts revs with great enthusiasm. It’s within the mid-range, where all that torque is concentrated, that it’s at its savage best. There’s an engaging keenness and silken smoothness to the delivery, so much so that the 7000rpm ignition cutout seems rather conservative.

Channelling drive to each wheel is an eight-speed ZF automatic gearbox with a beefed-up torque converter as well as Alpina’s Switchtronic manual shift function, via either buttons or paddles on the steering wheel. It operates in combination with BMW’s xDrive four-wheel drive system and a reworked version of BMW M’s electronic M Sport rear differential.

There’s a fitting urgency to the shifts in each of the three driving modes: Comfort, Sport and Sport Plus. As with the engine, there’s an appealing smoothness of operation and a feeling of deep-seated engineering to the gearbox, in both automatic and manual modes. The gearing itself is superbly judged. If you’re in the market for a B3, though, be sure to choose the paddle-shift option. The button shift is nowhere near as satisfying to use.

Alpina quotes an official 0-62mph time of just 3.8sec for the B3 saloon, making this the fastest-accelerating 3 Series-based model it has placed into production. Such is Alpina’s confidence in the B3’s straight-line stability that it doesn’t restrict top speed, which is a claimed 188mph.

The B3 is softer than the new M3 – not considerably so but sufficient to give it an appeal all of its own. Its chassis has been extensively reworked with Eibach springs and stabilisers as well as reprogrammed adaptive dampers from the M340i. It also gains greater negative camber at each wheel. The standard 19in forged rims are shod with bespoke 265/35 front and 275/35 rear Pirelli P Zero tyres that have been developed specifically for the new model. Bovensiepen says: “It wasn’t our intention to make a more sporting car than the M3. Our philosophy is always to create a car that is sporting but also with comfort for long distances – a relaxing and smooth car that you can get out of after long journeys and still feel good.”

It steers with an alert action, proving engaging even on the most mundane of roads. There’s a lovely maturity to the way the whole chassis operates, with carefully judged compression and rebound properties giving it a nicely controlled yet an authentically athletic feel. Road shock is dealt with quickly before it has a chance to unsettle your chosen line, even when loaded up in corners over bad surfaces. Body control is also exemplary, with very little lean.

The standard adaptive dampers have two modes: Comfort and Sport. The additional Sport Plus mode delays the action of the recalibrated stability control function but retains the same damper characteristics as in Sport. Even in Comfort, it turns in sharply, with abundant grip and great poise. Switch to Sport Plus and it serves up progressive power oversteer that is so benign and controllable that you wonder why BMW just doesn’t take the chassis tune for the M3 itself.

How does the B3 compare to the BMW M3?

Alpina is not as closely focused on running at the Nürburgring’s Nordschleife circuit during development of new models as BMW M. “We go there, but only for some set-up functions. Our suspensions are mainly tuned on German country roads and autobahns – not the Nordschleife,” says Bovensiepen. “Our philosophy is to build a car you can drive all day, not just a lap or two.”

It shows. The B3 is a brilliantly balanced and rounded machine – responsive and direct but not at the expense of comfort and ride refinement. As Alpina suggests, it’s a car you can rely on to take you long distances at high speed and with a high degree of entertainment without it being wearing on the driver.