For Alpina, a technology driven company, standstill is a foreign word. Since the introduction of the B7 Bi-Turbo, the engineers from Buchloe, Germany, have been continuously working on the details of the turbo charging and intercooler system.
Consequently, the all-aluminium V8 power plant now produces 540hp (397kW) at a moderate 5500rpm, with a maximum torque of 700Nm from 3000rpm. Two turbo-chargers configured in parallel, each feeding one of the two cylinder banks, with specially developed large diameter exhaust-turbines allow this engine configuration to provide both exceptional power output and an abundance of torque over an especially broad rpm range while maintaining excellent throttle response at low rpm.
The comprehensive high-performance cooling system comprises an indirect inter-cooling system (air-to-water/water-to-air) with short intake tracts and increased inter-cooler flow. The systems excellent thermodynamic efficiency is guaranteed by a large-volume low-temperature inter-cooler radiator, two water-to-air intercoolers placed close to the engine and additional separate motor oil and water coolers.
High-performance MAHLE pistons are designed specifically to deal with temperatures and pressures associated with up to 1.0 bar charging and the engine's 9.2:1 nominal compression ratio. Altogether this results in an impressive specific output of 122.7hp (90kW) per litre and a mean total compression of 20.1 bar. Direct injection and Double-VANOS contribute to the B6 Bi-Turbo's class-leading consumption and emission figures: 10.5 (10.6) l/100km and 244 (247) g/km CO2, Combined cycle, measured according to ECE Norm (data for Convertible in brackets).
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