Alpina is well known for their re-worked versions of BMW cars. While in the past they aimed to produce a more distinguished alternative to BMW’s M cars the latest generation offer something a bit different. The Alpina B4 Bi-Turbo Convertible has an upgraded version of the 435i engine designed for both power and economy thanks to a twin turbocharging system replacing the normal twin-scroll unit. To withstand the extra stresses bespoke components include a sophisticated cooling system and a new, forged steel crankshaft are fitted.
The 3-litre engine offers nearly as much power and even more torque than a BMW M4, but the intention is not to make a track orientated car. The B4 has been developed to give useable power that is effective under normal road driving conditions. A four-wheel-drive version is also available for left-hand drive markets which further reduces the 0-100km/h time by a couple of tenths.
The suspension springs and anti-roll bars are firmed up to give more responsive handling without losing the focus on real world performance and comfort.
Styling is subtly changed to give the car a distinctive look without standing out as heavily modified. Bespoke leather upholstery and luxury carpets come as standard and there are plenty of Alpina logos dotted around the interior to remind you that it is something special.
The acoustically insulated metal convertible roof can be closed in just 20 seconds at speeds up to 18 km/h (11 mph).