Engine/GearboxWhen the car arrives at Alpina, the engine is completely dismantled, as always. Then they fit forged Mahle pistons, to bring the compression down to 7.2:1, they rebalance all moving pieces and remachine the combustion chambers. The new pistons, which have oil-spray cooling of the undersides, are married to stronger connecting rods. New valves, which is sodium-cooled on the exhaust side, and a new camshaft are also fitted. The intake and exhaust systems are Alpinas own. They include new exhaust manifolds supplying twin Garrett T25 watercooled turbochargers with an integrated, electronically controlled wastegate feeding the engine through a huge intercooler, which stretches from just below the kidney grille down to the bottom of the spoiler. The good thing with two small turbochargers is that the same boost is possible as from a single larger unit but without the lag. Fuel injection and ignition are reprogrammed Bosch Motronic. The Alpina exhaust system(manufactured by BOYSEN) is made of stainless steel and includes six metal-core catalysts with Lambda-Sond control. The result at full boost, the B10 BiTurbo has variable boost control made by Bosch(variable between 0,4-0,8 bar), is an output of 360 bhp and 520 Nm of torque. That is a little bit more than the standard BMW 535i clutch and gearbox can take so Alpina have fitted a stronger Fichtel & Sachs clutch and a 5-speed gearbox, specially developed by Getrag, transmit the drive to the beefed-up rear axle, which includes a 25-percent limited-slip differential.
Suspension/Brakes/WheelsLinear-rate springs are used all around with anti-roll bars and Bilstein-damped front struts. At the rear, the Fichtel & Sachs shock absorbers also control the ride height, which is hydraulically adjusted by an electronically operated high-pressure system. The 17in Alpina alloys make room from larger-than-standard Girling brakes with Lucas 4-piston front calipers. They are of course ventilated all around. The low-profile Michelin tires are 235 mm wide at front and 265 mm wide at rear.
Interior/ExteriorInside, the seats are replaced by Alpina´s own sportseats, manufactured by Recaro. They are covered with anthracite Alpina cloth. A leather-covered steering-wheel, which is made by Momo, is also fitted. As is a polished wood interior. The B10 also have new instruments and digital-indicators for engine-oil and rear axle-oil temperature and for turbo boost and oil-pressure. The exterior changes include a front spoiler, rear spoiler, the exhaust pipes and the wheels. The stripes are optional. The last 50 cars have the wider kidneys like the V8-engined 5-series cars and the new rearview mirrors. The cloth-interior is changed to the ultra-luxurious "Alpina-wasserbüffel" leather-interior. They also have new blue instruments and a new rear spoiler.
PerformanceAlpina claimed a 0-100 km/h time of 5,6 seconds and a top speed of over 290 km/h. 200 km/h is passed after around 19 seconds.