Difference Between a V16 & W16by Herb Kirchhoff
Sixteen-cylinder engines have always been symbolic of power and luxury in an automobile, from the Cadillacs and other luxury makes of the 1930s to the modern road rockets like the Bugatti Veyron. Originally, 16-cylinder engines were made in a V configuration but in recent years auto engineers have developed a W configuration for eight-, 12- and 16-cylinder high-performance engines.
The V type engine dates back to World War I, but the V8 engines introduced by Ford in 1932 popularized the V type automobile engine for all time to come. The typical V8 consists of two inline banks of four cylinders each, offset by 60 to 120 degrees of arc. This makes for an engine shorter but wider than inline 8-cylinder engines, requiring a larger engine compartment volume. The V8 also requires two cylinder heads and a complex intake manifold for even fuel distribution. V16 engine designs of the 1930s and later followed the pattern of the V8, but with two inline banks of eight cylinders each. V16 engines are long and require a long engine compartment, making them difficult to mount in modern cars.
W Engine's Parent
The W engine configuration grew out of the VR6 engine developed by Volkswagen in the late 1980s for the performance packages on its lower mid-range vehicles like the Jetta, Passat and entry-level Audi models. The VR6 has two staggered rows of three cylinders, with the rows offset by 15 degrees in a single engine block. The cylinders are covered with a single head having separate intake and exhaust valve camshafts. The result is a compact engine shorter and narrower than a conventional V6 but just as powerful, ideal for transverse mounting in a vehicle.
Enter the "W"
When Volkswagen in the 1990s entered the performance luxury market with new Audi models and acquisition of Rolls Royce/Bentley and Bugatti, Volkswagen engineers wanted compact power. They developed the W configuration by joining two VR engines at the crankshaft. They created a W8 by joining two VR4 blocks at a 72-degree angle and a W12 by joining two VR6 blocks at the same angle. For the W16, the engineers joined two VR8 blocks at the crankshaft. These W engines got the name because the axis lines for the four rows of offset cylinders in the two VR blocks form a letter W, just as the axis lines from the two rows of inline cylinders in a V8 form a letter V.
Into the Cars
As of June 2011, Volkswagen is the only auto maker putting W engines in road cars. It has installed a W16 in the Bugatti Veyron, a W8 in the VW Passat and a W12 in certain Audi, Rolls and Bentley models. As for the V16, there are no modern production cars using this type of engine, although an Italian venture firm in 1995 put the Cizeta-Moroder V16T into limited production with a transversely mounted V16 engine. But it made only 10 of the $400,000 cars before it folded. The V16 configuration is far from dead, however. It is used in locomotive, marine and industrial diesel engines.
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