According to its maker, the Alpina D3 is the world’s fastest diesel production car, which is hardly surprising given that it mates the regular BMW 3 Series’ four-door and estate bodyshells with 345bhp and, get this, the hardly insignificant matter of 516lb ft of torque.
The D3’s motivational forces are provided by a heavily tweaked version of BMW’s regular 3.0-litre, twin-turbo straight six diesel engine. Internally, the BMW motor is all but untouched but by fitting new, slightly smaller variable-geometry turbos and then tweaking the intercooler and fuel systems accordingly, Alpina has unleashed a fair bit more power and a whole heap more torque.
And the whole lot reaches the road via a similarly tweaked BMW eight-speed automatic transmission, with Alpina’s customary shift buttons being stitched into the back of the steering wheel to enable manual changes. The gearbox software has been rewritten to provide a greater range of characteristics on the move. Select Comfort in the dynamic drive program and both the ride and gearchange responses become even softer and even smoother than they are in a regular 3 Series.
Select Sport or Sport Plus, however, and the ride and gearchange responses become sharper and crisper than standard, or so goes the theory. In reality, the spring rates are 40 percent stiffer all round no matter what program you select, and the anti-roll bars, bushes and bump stops are all bespoke to the D3, too, giving it a more dynamic set of ride and handling characteristics compared with the basic 3 Series at all speeds, and in all settings on the move.
