BMW Alpina B10 Bi-Turbo (E34) quick look

In March 1989, at the Geneva motorshow, Alpina introduced their fastest car thus far, the B10 BiTurbo, based on the 535i. The B10 BiTurbo took two years to develop and cost a staggering $3.2 million in R&D. But it paid off. The 3.5 litre, twin-turbocharged six-cylinder engine is considered to be one of the best turbocharged engines ever. In the September 1991 issue of Road & Track magazine, Paul Frère wrote: “For me this is the car … I think this is the best 4-door in the world”. Despite a base price tag of 146,800 DM, nearly twice the price of an E34 M5, the B10 BiTurbo became the best-selling model in Alpina history up to that point. Production ended in 1994 due to termination of the M30 engine by BMW. The last examples of the 535i with M30 engine were delivered by BMW to Alpina for producing the final 50 examples of the B10 BiTurbo. ENGINE/GEARBOX The stock BMW 3.5 liter engine is completely dismantled. Alpina installed forged Mahle pistons, re-balanced all moving pieces and re-machined the combustion chambers. The new pistons, which have oil-spray cooling of the undersides, are installed with stronger connecting rods. The pistons bring the compression ratio down to 7.2:1. New valves – sodium-cooled on the exhaust side – and a new camshaft are also fitted. The intake and exhaust systems are Alpina’s own production. The new exhaust manifolds include twin Garrett T25 water-cooled turbochargers with an integrated, electronically controlled wastegates feeding the engine...