BMW and ALPINA have long had a history of working together to produce special BMW automobiles. Burkard Bovensiepen, son of the founder of ALPINA Business Machines and an enthusastic racing driver/engineer, began his automotive career path in 1961 by developing a dual-carburetor setup for the just-introduced BMW 1500 sedan. It was a predictive beginning: to take an already fine-performing BMW (which also just happened to be a practical sedan) and making it perform even better.
By 1964, BMW had officially recognized ALPINA’s contribution to BMW performance and offered warranty coverage on ALPINA-equipped BMW vehicles. Not long thereafter, Burkard Bovensiepen founded the ALPINA company – ALPINA Burkard Bovensiepen KG – that continues today, creating special versions of BMW automobiles that offer a particular brand of performance for discriminating auto enthusiasts. Yet outside the circle of dedicated BMW enthusiasts, ALPINA has kept a low profile in North America. In addition to racing versions of BMW, ALPINA has developed a progression of BMW-based cars based on 3, 5, 6, 8, Z4 and Z8 models and offered them on a limited-production basis. Up to now, the only BMW ALPINA model offered by BMW of North America has been the 2003 ALPINA ROADSTER V8, a special interpretation of the Z8 Roadster of which 450 examples were delivered to U.S. customers.
The latest manifestation of the unique BMW-ALPINA synergy is the B7, based on the BMW 7 Series luxury sedan. Currently, BMW offers ultra-performance models of its 3, 5, 6 and Z4 Series developed by BMW M, BMW’s own performance subsidiary. BMW M’s automobiles have specific performance character, typified by high-revving engines and manual or sequential-manual (SMG) transmissions. For an ultra-performance version of the 7 Series – a platform that is defined by lavish luxury and generous interior space and offered only with an automatic transmission – something other than “M” performance character was called for.
In recent models, ALPINA has concentrated on delivering very high levels of performance with moderate rpm ranges and automatic transmission. Most appropriately, the new BMW ALPINA B7 applies this philosophy to the 7 Series to produce a luxury sedan of stunning performance. “A 7 Series Beyond,” one might say.
ALPINA is located in the small Bavarian city of Buchloe, some 50 miles southwest of the capital of Bavaria, Munich, where BMW’s worldwide headquarters are located. For more information on ALPINA the company, see the accompanying release.
ALPINA B7: a “7” of unique character
BMW itself offers a 7 Series model powered by a 438-horsepower V-12 engine, the 760Li. It is indeed a high-performance car, combining the velvety and high-torque power delivery of a 12-cylinder engine with ultimate luxury. For an unabashedly sporty interpretation of the 7 Series, ALPINA chose the path of supercharging BMW’s V-8 engine.
By selecting as the basis for the B7 the BMW 750i, with its V-8 engine and regular-wheelbase platform, ALPINA could achieve a vehicle weight some 400 pounds lighter than that of the 760Li – a benefit in terms of agility and maneuverability. Then, to attain a power target of 500 hp, ALPINA added a supercharger to the V-8 engine, which adds little weight but lots of horsepower.
The supercharged engine: V-8 + Valvetronic + Kompressor = 500 hp
At the time ALPINA began development of the B7 engine, BMW’s V-8 engine with Valvetronic – the unique system that regulates power output by varying intake-valve lift – was at a 4.4-liter displacement in the 745i, not the 4.8 liters of today’s 750i. Therefore, the engine package was based aroung 4.4-liter’s 325 hp @ 6100 rpm and 330 lb-ft. of torque @ 3600 rpm. ALPINA took on the challenge of supercharging a Valvetronic engine, something that had never been done before. To tell something of the ending before the story, the achievement is impressive: 500 hp @ 5500 rpm and 516 lb-ft. @ 4250 rpm. In German, such figures qualify as bullig and no translation is necessary to get the meaning.
Both supercharging (in German, a supercharger is a Kompressor) and turbocharging have their attractions as power-enhancers for combustion engines. A supercharger is mechanically driven by the engine; a turbocharger is driven by streaming exhaust gas. In this case the supercharger’s salient points include lag-free response, relative quietness, low exhaust back pressure and the ability to run the engine at part load (i.e. most of the time) just as it runs without the supercharger: with Valvetronic regulating its output. These last two factors speak for good efficiency and reasonable fuel economy in everyday driving.
These two elements allow the engine to be controlled by Valvetronic up to the point where the intake valves have reached their maximum opening via Valvetronic; it also helps minimize any pumping losses in the supercharger, which under these conditions is essentially “coasting.” At this point, the pressure regulator before the supercharger becomes the engine throttle, responding to the driver’s accelerator-pedal input and regulating the supercharger’s boost accordingly. Sensing and regulation functions to execute this strategy are included in the engine’s electronic control system. This entire system was developed, and is patented, by ALPINA.
The supercharger itself is a new development. It’s of the Radial or Nautilus type, not a brand-new concept as such but now appearing on an automotive engine for the first time. It had been patented by ZF in the 1980s, but only recently have metallurgical advances made this actual vehicle application possible. (In connection with the B7, ALPINA has several patents pending.) At full boost, the supercharger delivers a positive induction pressure of 0.8 bar.
There is a clear subjective difference between an M-type exhaust note and that of the B7. Being high-revving, M engines emit a relatively high-pitched exhaust sound. The ALPINA B7 engine, with its lower-rpm range and emphasis on big torque, just as naturally – and despite the measures to keep low-frequency sound in check – puts out a lower-pitched sound. Commenting on this sound in everyday driving, the April 4, ’04 issue of Germany’s auto motor und sport magazine called it “Gently murmuring, acoustically not unlike a costly Riva boat, the V-8 pulls away and shows with great refinement that there’s also driving pleasure at less than 500 hp.”
Predictably, on-the-road performance results from the intense development effort are dramatic when all 500 horsepower are put to use: 0-60 mph comes in 4.8 seconds and a maximum speed of 186 mph is achieved. Unlike regular-production and even M-version BMWs, the B7 does not have an electronic speed limiter. And for those times when one is not able to utilize the full 186 mph or run the stopwatch from 0 to 60, the supercharged V-8 puts down abundant thrust in the ranges where one drives much of the time: from as low as 1500 rpm, it can deliver nearly 300 lb-ft. of torque.
Fine-tuning the 7 Series chassis
Using the already advanced and sharp-handling 7 Series chassis, ALPINA fine-tuned the hardware to the B7’s higher performance level. While retaining the regular models’ Active Roll Stabilization – which counters body roll or “lean” in corners via electronics and hydraulics – ALPINA’s engineers, working with BMW and tire supplier Michelin, adopted a firmer calibration of springs and shock absorbers. They also chose the European 760i’s brakes, which have larger dimensions than those of the 750i:
And, where the rubber meets the road, ALPINA topped even the 2006 BMW 760i’s standard 20-in. wheels and tires by upping it to 21 inches. Right from the days of its participation in developing the lightweight BMW 3.0 CS of the early 1970s, ALPINA has a long tradition of radial-spoke wheels; this carries on in the B7’s massive 21 x 9.0-in. front and 21 x 10.5-in. rear wheels with a traditional count of 20 slender spokes. These provide for outstanding ventilation of the big brake rotors, and carry Z-rated performance tires of 245/35 front / 285/30 rear dimensions.
One “final” B7 measure, adoption of the 760Li final drive, completes ALPINA’s powertrain and chassis development. ALPINA engineered some strengthening modifications to this differential unit, which have now flowed into BMW’s own production of that model. And yet even with this strengthening, the supercharged V-8’s torque is so massive that it is electronically limited in the transmission’s bottom two gears.
The effect is one of subtle performance emphasis, fully appropriate to the 7 Series’ elegant and substantial presence but leaving no doubt that this is a special 7. Inside the B7: special instrumentation and controls, exclusive ALPINA choices All 7 Series BMWs offer their occupants lavish luxury, fine materials and tasteful design. To this sumptuous ambiance, ALPINA adds its own touches, both ergonomic and aesthetic, to a level beyond that of a regular-production 7 Series.
Special ALPINA features. First and foremost, it’s performance that characterizes the B7. And once seated behind the special ALPINA steering wheel, the B7 driver is quickly and keenly aware of this emphasis.
Upon stepping in over the handsome B7 doorsill trims and setting his or her foot on the fine floormat with its ALPINA logo, the driver can assess an instrument cluster with the traditional ALPINA Blue as its background color and ALPINA lettering at bottom right. Four readings from the iDrive system’s On-board Computer can be called up conveniently via a button on the turn-signal stalk: remaining fuel in tank, range on fuel, distance to destination and a digital display of current vehicle speed.
Other distinguishing features of the B7’s instrument cluster include longer, red pointers with blue centers; deletion of the 7 Series’ chrome dial rings; a 200-mph/320-km/h speedometer scale; and constant display of the current transmission gear, even in the automatic mode.
The steering wheel itself presents distinctive visual character and function: in its center, the ALPINA logo; on its rim Lavalina leather and special stitching, plus symbols for the SWITCH-TRONIC transmission’s upshift and downshift buttons. These “+” and “-” inscriptions are in ALPINA Blue, and denote the actual locations of the shift buttons on the wheel’s forward side (away from the driver).
Interior upholstery and trim selections consist of the four standard BMW colors for the Nasca leather and a choice of American Walnut or high-gloss Ash wood trim; a B7 in ALPINA Blue exterior color will also include ALPINA’s stunning Myrtle wood interior trim. These amenities are in addition to the very extensive standard equipment of even the most accessible 7 Series models, the 750i; for a complete listing, see the standard & optional features listing included with this presskit.
Available options: so much is standard, this list is short
With so much of the equipment that’s optional on or in the V-8 7 Series models and standard in the V-12, the list of available options for the BMW ALPINA B7 is understandably short. Here, briefly described, are the Package and stand-alone options that are available:
Rear Entertainment Package, offering rear-seat passengers their own entertainment and feature-control options. Includes a color monitor, 6-disc DVD changer and two headphone jacks; when allowed by the driver, rear passengers can operate certain iDrive functions via their own controller.
BMW Night Vision. Recently introduced in other BMW models; improves the driver’s vision at twilight and night. An infrared camera captures the view up to about 300 meters/1000 ft. ahead of the vehicle; the resulting image is displayed on the central iDrive monitor. The warmer the object, the brighter it appears; thus human beings and animals are visually emphasized.
Thanks to the system’s excellent range, the driver can be aware of hazards (and living creatures!) in the road ahead a good 11 seconds sooner at 70 mph than might otherwise be the case. Active Cruise Control. Employs a radar sensor unit at the front of the vehicle to sense the speed of vehicles traveling ahead, and accordingly adjusts the BMW driver’s speed to help maintain a safe following distance.
High Definition Radio. BMW is the first automaker to offer this feature, which provides digital-quality sound on FM and improves AM sound to quality approaching that of conventional FM.
In contrast to Satellite Radio, HD Radio is broadcast from terrestrial towers by the radio stations that offer it, and requires no subscription. The compressed digital signals promise the possibility of more stations within the bandwidth used by one station today. Presently, some hundreds of stations are broadcasting digitally, and the number is expected to grow. Rear-seat side-impact airbags, offered as an option in all models so that customers can decide whether or not to equip their vehicle with this feature.
Text and photos courtesy of Alpina