The B7 is based on the BMW 745i which has a 4,4-litre V8 producing 333 bhp. The most important change Alpina have made to the engine is fitting a supercharger, which makes the B7 the first supercharged Alpina ever. It produces 500 bhp and has a torque of 700 NM. BMW´s top-of-the-line 7-series, the V12 equipped 760i/Li has 445 bhp and 600 NM. The B7 is more powerful and weighs around 150 kg less. This makes the B7 much more of a driver´s car than the 760i/Li. And of course, even more exclusive.
In March 2003, at the Geneva 2003 motorshow, a prototype of the B7 was shown with 470 bhp and 650 Nm. Later in the year, at IAA 2003, the same car was presented with 500 bhp and 700 Nm. This power difference is likely due to the launch of the E60 M5 whose official power output Alpina didn’t want to exceed.
In February 2006, at the Canadian Autoshow, BMW surprisingly announced the launch of the B7 in North America. Please read about the NA-version on a separate page.
The B7 uses a supercharged V8-engine based on BMW´s 4,4 litre unit, found in the 545i and the 745i for example. In standard version it produces 333 bhp, in Alpina´s version it delivers 500 bhp. The main difference between those engines is that the Alpina engine is supercharged. But don´t think that Alpina just bolted a stock supercharger onto the BMW engine and that was it. The block is similar to BMW´s version, but has been ordered to Alpina´s own specifications. The crank is forged, instead of cast and lower compression pistons from Mahle are used. The supercharger itself is unique too, and is actually patented. Here is what Alpina says about the engine:
“The engine’s forced induction differs from conventional solutions: it is neither turbo, nor of the type of super-chargers that drain a great deal of power from an engine, especially at higher rpm. A radial or ”Nautilus-type” compressor delivers the ALPINA V8’s boost pressure: one might see it as a combination of super-charger and turbo-charger. It isn’t propelled by exhaust gases, as a turbo would be, but rather belt-driven from the crankshaft. The inner workings of the radial compressor compare to the intake side of a turbo: a small turbine generates up to 0.8 atmospheres of boost to the cylinders. Before reaching the engine, the air passes through a generously-dimensioned inter-cooler, capable of sinking intake air temperature up to 70°C. The advantages of this innovative technical solution? The radial compressor never stops spinning, with no time lag when power is demanded. Under the types of low to partial loads found in everyday driving, the engine operates as if it were normally aspirated, using the full functionality of Valvetronic (variable valve lift). This is the deciding factor in creating advantageous fuel economy. The compressor is controlled through the use of an ”upstream” throttle plate in the intake system – a development unique to ALPINA, and one that makes the charging of the Valvetronic V8, without the use of a common throttle body, even possible.”
Naturally, Alpina have also worked a lot on the electronic systems to make the engine as efficient and driveable as possible. To sum it up the Alpina engine is actually made of about 1/3 BMW parts, 1/3 parts from BMW suppliers and 1/3 parts from Alpina´s own suppliers. As mentioned above it delivers 500 bhp at 5500 rpm and has a maximum torque of 700 NM from 4250-5250 rpm. The gearbox is the same ZF 6-speed automatic as used in the BMW cars, but gets strengthened first and second gears, a new torque converter and reprogrammed software. And as always, it also features Switch-Tronic.
The wheels are 21″ with 255/35 tires at front and 295/30 at rear. Behind them, Alpina have fitted larger brakes from the 760Li. The discs measure 374 mm at front and 370 mm at rear.
Inside the B7 is equipped with sport seats in Alpina design leather, new instruments with blue background and red needles, luxury wood “Myrtle”, a hand-stitched leather steering-wheel, Alpina floor mats, Alpina door sills and a silver-plated production plaque. The exterior changes are very subtle, front and rear spoiler lips are fitted, which make the car more stable at speed while maintaining a low CW-value.
For the B7, Alpina claimed a 0-100 km/h time of 4,9 seconds, 5,1 for the Longversion. Although Alpina state the topspeed as 300 km/h, in Auto Motor und Sport´s high-speed test at Nardo the B7 drove an impressive speed of 311 km/h. At a later event, an Alpina customer drove a B7 at 325 km/h.