powertrain
First class performance and economy
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 5200-6250rpm, with a maximum torque of 730Nm from 2800-5000rpm. 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 1.2 bar charging and the engine’s 10.0:1 nominal compression ratio. Altogether, this results in an impressive specific output of 123hp (90kW) per litre and a mean total compression of 20.1 bar.
Direct injection and Valvetronic ontribute to the B6 Bi-Turbo’s class-leading consumption and emission figures: 10.1l/100km (Convertible: 10.2l/100km) and 234/km CO2 (Convertible: 237g/km) (Combined cycle, measured according to ECE Norm).
Transmission – Eight-Speed All-Rounder
Adapted and tested in co-operation with ZF, the advanced SWITCH-TRONIC 8-speed Sport Automatic Transmission sets benchmarks. With ALPINA’s philosophy the guiding credo, engineers have spent thousands of development and test hours ensuring that no other performance automatic transmission comes close to providing this level of both comfort and performance.
The blend of eight speeds and plenty of torque makes for unparalleled comfortable gear changes with no noticeable interruption to the delivery of power – only the accompanying acoustics and the dynamic rev counter provide feedback as to the workings of the transmission.
The 730Nm of torque mean that the B6 Bi-Turbo excels at cruising along at speed in a high gear at minimum rpm, benefiting both consumption and comfort.
Using the Sport (S) Shift Mode a completely different character emerges: the transmission is crisp and unmistakably immediate. The innovative single-cylinder fade-out (known as 'Einzelzylinderausblendung‘ in German) enables super quick up-shifts which take just milliseconds. Depending on the load on the transmission, the injection of fuel into a given cylinder is interrupted for a fraction of a second, creating the required reduction in torque that the automatic transmission needs for the up-shift. The advantages versus the typical method of timing retardation are noticeably quicker shifts, improved thermo-dynamic efficiency due to reduced exhaust temperatures and lower fuel consumption. Each up-shift is accompanied by a deep back-pressure burble.
The SWITCH-TRONIC buttons, for use in the Manual (M) Shift Mode, are ergonomically and unobtrusively positioned on the back of the steering wheel, and allow the driver to take complete control of the transmission. The system allows for multi-simultaneous down-shifts in milliseconds, hereby the transmission will skip several gears depending on engine loads and rpm. In this manner the 8-speed Sport Automatic Transmission with ALPINA SWITCH-TRONIC reveals itself as extremely multi-faceted, providing the right shift characteristic for any and all situations.
The Automatic Up-Shift function means that the transmission will up-shift into a higher gear once a certain rpm threshold has been passed in the current gear. In certain driving situations this may not be desired, for example during especially sporty driving or for example when encountering multiple tight hair-pin corners. The simultaneous selection of either Sport, Sport+ or DSC OFF Mode using the Drive Dynamic Control button and the selection of the Manual (M) Shift Mode (transmission) will deactivate the automatic up-shift function. The transmission will hold the selected gear up to maximum rpm’s (electronically limited) and will not automatically up-shift into a higher gear.
The intelligent coupling of state-of-the-art engine and transmission technologies give the B6 Bi-Turbo stunning performance figures: 0-100km/h in 4.3s (Convertible: 4.4s), and a top speed of 320km/h (Convertible: 317km/h).
Titanium Exhaust System made by Akrapovic
Special consideration was given to the development of the exhaust system in the
B6 Bi-Turbo Convertible. A person’s sense of hearing is particularly heightened when driving with the top down, almost craving for a fantastic sound experience. For the first time, ALPINA has collaborated with Akrapovic on the development of a lightweight exhaust system made from high-strength titanium.
Faithful to the guiding principle of ‘form follows function’, the entire system is noted not only for its acoustics and appearance, but also for its technical refinements. In addition to a weight-saving of 50% compared to the conventional use of stainless steel, the exhaust system also boasts impressive technical details. The engineers from ALPINA and Akrapovic have achieved quite a feat, managing to retain a diameter of 2 x 70mm throughout the entire length of the exhaust system, despite the tricky ‘packaging’. In conjunction with further design refinements, exhaust back-pressure is reduced to an absolute minimum.
In interaction with the powerful engine, the exhaust system generates a backdrop of deep, sonorous eight-cylinder sound – powerful, sporty, but never obtrusive, due to intelligent, controllable exhaust valves. These offer the driver a special degree of influence over the sound experience, and can be controlled using the Drive Dynamic Control. In Comfort+ and Comfort Mode the valves are closed, opening at 3000rpm, regardless of the selected gear. In 1st and 2nd gear decisive use of the accelerator will cause the valves to open (at approx. 60% load) and the B6 Bi-Turbo to elicit a special symphony from the tailpipes during
dynamic bursts of acceleration. As befits the character of the B6 Bi-Turbo in Sport and Sport+ Modes, the exhaust valves remain open at all times.