2003 BMW Alpina Roadster V8

(from BMW Press Release) Woodcliff Lake, New Jersey, December 2, 2002…This new edition of BMW’s contemporary classic roadster is sure to raise eyebrows. A Z8 with an automatic transmission? A new Z8 powered not by the BMW M engine, but rather by a specially developed, higher-performance version of BMW’s “regular” V-8 engine? A new Z8 with 20-inch wheels and tires in place of the original model’s 18-inchers?

Yes, it’s all true, and there’s quite a story here. For starters, this new Z8 is not only from BMW, but also from ALPINA. Located in the Upper Bavarian town of Buchloe, ALPINA was established in 1964 as an official and approved “ennobler” of BMW automobiles – and with that word, we unabashedly translate directly from the German word Veredler, which tells us that ALPINA is not concerned merely with making BMWs go faster and look racier. Instead, ALPINA’s tradition is to take production BMWs and make them even more appealing to connoisseurs of automotive finery. Performance finery, we must add, as ALPINA’s treatments include not merely cosmetic modifications but also a palette of powertrain and chassis refinements that consistently enhance BMW models’ already formidable road capabilities within a context of thorough engineering and mature character.

ALPINA has transformed the Z8 in a thoroughly logical way, consistent with its own long-standing principles and the tastes and preferences of ALPINA founder Bovensiepen himself. Toward an understanding of the ALPINA transformation of the Z8, it is helpful to bullet-point the ways in which the ALPINA roadster differs from the original Z8 – whose limited production concludes today with a total of approximately 5,000 units having been largely handbuilt:

• Most dramatically, the BMW ALPINA ROADSTER V8 replaces the Z8’s BMW M engine (5.0 liters, 394 horsepower, elaborate individual throttles for each of the eight cylinders and many other racecar-like engineering characteristics) with a performance-developed version of BMW’s “regular” V-8 engine. Remarkably, the 4.8-liter ALPINA engine comes to within 19 hp of the BMW M unit (375 hp, vs. 394), does so at lower rpm levels, and (this is key) is thus suited to teaming with an automatic transmission. Its power peak comes at 5800 rpm, vs. 6600; its torque peak occurs at the same 3800 rpm but is actually higher: 383 lb-ft. (vs. 368 lb-ft). Put another way, the ALPINA engine delivers at least 368 lb-ft. all the way from 3100 to 5000 rpm.

• In another significant departure from the original Z8, and in harmony with the new engine, the 6-speed manual transmission is replaced by a special BMW ALPINA automatic transmission.

• Also dramatic: special BMW ALPINA 20-inch wheels, with five clusters of four spokes each. With 9.0-in. width at the front and 10.0 at the rear, these wheels are an inch wider at the front and carry Y-rated performance tires of dimensions 255/35R-20 at the front and 285/30R-20 at the rear. Z8 wheels and tires are 18-inchers, the tires being 245/45 at the front and 275/40 at the rear.

• Y-rated performance tires are a departure from Z8 practice too. The Z8 wears W-rated run-flat (also performance) tires; the ALPINA’s tires balance their lower profile (which implies firm sidewalls) against Z8’s higher-profile, but still relatively stiff run-flat sidewalls. (20-in. run-flat tires would have been unacceptably harsh-riding.) At the bottom line, sensitive drivers will find the BMW ALPINA ROADSTER V8 to deliver increased riding comfort with at least comparable handling.

• For the eventuality of a flat tire, the ALPINA model employs the BMW Mobility System, familiar from BMW M models. BMW Mobility consists of a container of rapid sealant, an integrated micro-compressor, and a hose to connect the compressor to the damaged tire. All this is carried in a trunk recess near the right rear wheel, designed into the Z8 right from the start. The system can seal punctures up to approximately 1/4 in. across.

• Retaining the Z8’s power telescopic adjustment, the BMW ALPINA ROADSTER V8 adopts a different steering wheel, with three leather-and-metal-finished spokes in place of the Z8’s “banjo” spokes. An ALPINA logo replaces the BMW emblem on the steering wheel’s center hub.

• The cockpit is upholstered in Soft Nappa (distinctive from the Z8’s Nappa), with special piping and ALPINA logos in the upper seatback. Three color schemes are offered: Black/Black, Black/Crema and Black/Sport Red.

Production of the original Z8 for the U.S. concludes at the end of November ’02. Beginning on December 1, ’02, BMW and ALPINA will build 555 BMW ALPINA ROADSTER V8s, of which some 450 are for U.S. sale. Actual construction of the basic roadster platform runs from September ’02 through July ’03, with ALPINA’s engine construction beginning before that.

One could say that these cars begin life in Buchloe, as ALPINA receives about 1100 parts from which to build the engine. At ALPINA, the cast-aluminum cylinder heads’ intake and exhaust ports are polished by a team of six associates. A single master technician assembles the entire engine, which differs from the existing M62 V-8 engine variations as follows:

• The cylinder block, as cast by BMW in Alusil (aluminum-silicon alloy), has 93.0-mm cylinder bores. This is 1.0 mm greater than those of the 4.4i engine, and shared with the X5 4.6is engine.

• The crankshaft, with 89.0-mm stroke, is almost identical to that of the M5/Z8 engine; this stroke is 6.3 mm greater than that of the 4.4 engine, and 4.0 mm greater than that of the 4.6. The combination of 93.0-mm bore and 89.0-mm stroke produces a displacement of 4837 cc, vs. the 4.4’s 4396 and the 4.6’s 4619.

• ALPINA-specific lightweight aluminum pistons from Mahle, the famous German producer of pistons and other internal engine components.

• ALPINA-specific connecting rods, camshafts and valves. ALPINA-specific intake manifold, with increased volume and more sensitive air-mass sensors.

After assembly at Buchloe, the engine goes to Munich, where it is “married” to the transmission from ZF and the aluminum chassis/body structure from BMW’s dedicated aluminum facility at Dingolfing; suspension, steering and brake systems, paint, glass and safety systems are also installed in Munich. Final details are applied at ALPINA: steering wheel with SWITCH-TRONIC controls, interior panels, and other finish components. This process takes 5-7 days, after which the vehicles flow back into the BMW system for shipping.

Based on the 5-speed ZF unit employed in V8-powered 5 and X5 Series models, the ALPINA version differs in several major aspects:

• In addition to up- and downshifting by “tipping” the shift lever rearward or forward, the driver can also shift by pressing “+” and “-“ buttons near the steering-wheel rim.

• 1st and 2nd gears are strengthened to handle the engine’s higher torque. (Up to now, the largest, highest-torque V-8 teamed with this transmission has been that of the X5 4.6is.)

• Directly in front of the driver, a transmission display instrument indicates the range (P, R, N, D), mode (Automatic or Manual) and the gear currently engaged.

• Transmission software is unique to this unit.

Under wide-open throttle in its Automatic mode (D), the unit upshifts at 5800 rpm, the engine’s power peak. In its Manual mode (M), shifting is under the driver’s control but it will upshift at 6500 rpm to prevent engine overspeed.

On this last point, Germany’s auto motor und sport noted in its September 18, 2002 issue that “after the first phase of experimentation is over, there’s no need to shift for yourself. With its outstanding ratios, the automatic has the monumental power of this engine so totally in its grip that you don’t even need to kick down.” That’s a nice compliment, but we’re sure some drivers will want to take the shifting reins now and then.