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DaVinci Coders
January 23rd, 2002 at 12:04 pm

Volkswagen’s New W-8 Engine

Volkswagen has been re-engineering the engine. The W-8 eight-cylinder engine “can best be described as two narrow-Vee (15 degree) four-cylinder engines side-by-side in one block, sharing a common crankshaft.” Smaller, lighter, and able to leap tall buildings in a single bound…… well, maybe two bounds. What exactly is a bound?

More Here

Re-engineering
the
engine

The V goes
W at VW

—By Richard Mandel

It’s difficult to reconcile the idea that Volkswagen, once best known for the Beetle so ubiquitous with thrifty college students, is now an automotive titan that additionally owns Rolls Royce, Bentley, Lamborghini and the Bugatti marque. At least someone was successful after leaving school and entering business.

But it’s not just in mergers and acquisitions that has lent the company its record of success. VW has quietly maintained a tradition of distinctive German engineering while developing vehicles increasingly upscale for the company’s sales floors, refining components and systems for endurance and quality—moving yet further away from being the company that produced a car that remained virtually unchanged for more than 30 years.

So when Volkswagen decides to do something different, it is unlike anything seen before. And that’s a minimal description for the W engine.

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Repackaging

Volkswagen is no stranger to unique engine design. The original prototype of 1934, designed by Ferdinand Porsche, was powered by a horizontally-opposed, air-cooled, 700cc four cylinder engine that delivered 22 horsepower. Few companies were using air-cooled designs, and no one had a “flat-four” configuration (nor would there be until Subaru’s flat-four decades later). The 1938 production version displaced 986cc and developed 24 hp, and it wasn’t until the early fifties that power was raised to 30 hp.

The W-8 piston layout
(note the balancing shafts).

This model year sees the introduction of a new engine into Volkswagen’s already-popular Passat line. The eight-cylinder can best be described as two narrow-Vee (15 degree) four-cylinder engines side-by-side in one block, sharing a common crankshaft. The outside cylinders are splayed at 72 degrees, permitting it to fit within the same space of the V-6 currently used in the same vehicle. Displacement is four liters, with generated power of 275 hp (same as Cadillac’s 32-valve Northstar engine) and 273 lb-ft of torque. At 420 lb, it’s also lighter than nearly all other V-8 engines in the market.

the shorter W-8
crankshaft vs.a standard
V-8 crankshaft

the W-8 engine block

To fold eight cylinders into dimensions of 16.8 in. long by 28.4 in. wide (height is 27.3 in.), the W-8 engine requires more than merely a different layout of cylinder placement. New high-strength alloys permitted the connecting rods and their bearing surfaces to be flatter for closer positioning, and the combination of alloy technology and thinner connecting rods made for an accordingly shorter crankshaft. Each W-8 piston is about 1.2 oz lighter than the same component in the Passat V-6.

The engine’s ignition sequence alternates between the left and right sides, much as a racing engine operates for greater efficiency and higher torque. In order to achieve identical ignition timing with each 72-degree V-angle, the crank journals were offset by 180 degrees to each other, resulting in a flat crankshaft. There are four chain-driven camshafts. Each pair of cams—one dedicated to each side for intake sequencing, another for exhaust—has a hydraulically-controlled adjuster to shift intake and exhaust valve timing, further optimizing idle, torque and power curves as conditions dictate. The engine also sports two balancer shafts, counter-rotating at twice the speed of the crankshaft, to reduce vibrations.

Resizing

But the W-8 engine didn’t just spring up overnight, nor was it the first of its kind. In 1997, Volkswagen began taking to auto shows the first prototype for the Bugatti label, which the company had acquired earlier in the decade. It was a sleek, smooth sedan with a grill that clearly declared its lineage with its antecedents of the ’20s and ’30s. But as much a draw at auto shows as the restored name, was the powerplant, a leviathan of 18 cylinders in three rows—two in a standard Vee, and the third at approximately the three o’clock position as viewed from the front of the engine. Such a format—three rows of six cylinders versus two rows of nine—naturally allows a high-torque motor to be fitted to more practically-sized engine bays while permitting more conventional placement of the cabin on the chassis. The design was a first exercise, and after several years of refinement and study, the Bugatti EB 16-4 Veyron is about to go into production, powered by a quad-turbocharged engine of 16 cylinders in the W configuration as described above—two narrow-angle V-8s side-by side in a single block, sharing one crankshaft. The engine will be capable of developing 987 hp at 6,000 rpm and 922 lb-ft of torque at 2200 rpm. Installed ahead of the rear axle, the eight-liter industrial-strength powerplant will occupy an area of just 29 in. in length by 31 in. in width.

The W-16 for Bugatti

Fun though it would be to consume Dodge Vipers for breakfast, exotic motors dwell only in the narrowest part of the automotive market. Even if the Veyron is sold in this country for $200,000 a copy (reality check: the 12 cylinder Aston Martin Vanquish is tagged at $280K), there is a broader market (and profit, obviously) for selling eight cars at $35,000 to $40,000 each. Which was fair incentive for Volkswagen engineers to explore smaller versions of the W-16 engine.

More revisions

The eventual goal for Dr. Ferdinand Piëch, chairman of Volkswagen’s board of management, is to have a range of W engines from 1.8 to 8L available for all vehicles in a company stable that includes Audi with those already mentioned. He sees the torque-rich W-8 fitting in a space where others would use a V-6, probably as an option, and suggests similar logic for the other engines.

Currently being exercised on race courses is VW’s W-12 Coupé, using a 600 bhp prototype engine that set new records in speed on a 24-hour endurance course—4,402 miles at an average speed of 183 mph. A somewhat de-tuned version of the same engine, outputting a mere 414 hp, is slated to be an option for the Audi A8, as well as for VW’s first luxury class saloon (code named Project D1 at the time of writing) and the company’s entry into the SUV market, both due out later this year.

A very long distance from the 30 hp “people’s car.”

For more information:

Circle 345—Volkswagen AG, or connect directly to their website via the Online Reader Service Program at www.RSLeads.com/?201df-345

To see a brief animated view of internal workings of the W-8 engine, go to www.RSLeads.com/?201df-346

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