You are likely familiar with inline engines such as the I-4 and I-6, along with V6 and V8 setups. Fans of exotic sports cars may also recognize V12 and V16 powerplants. Less commonly discussed is the W engine layout. Inline designs place all cylinders in one row, V engines split them into two banks, and W engines arrange cylinders into three or four banks. These layouts trace back to the start of the 20th century. Alessandro Ambrogio Anzani developed the Anzani W3 for motorcycles he produced in the early 1900s. By 1909, this engine powered the Bleriot XI, the first aircraft to cross the English Channel.

Today, W engines are mainly linked to Volkswagen AG and evolved from its VR6 designs. The VR engines pack the two cylinder rows typical of a V engine so tightly that they share a single cylinder head. Placing two such VR arrangements on one crankshaft creates a W engine. A W8 uses two VR4 blocks, a W12 uses two VR6 blocks, and a W16 uses two VR8s. Since the early 2000s, W engines have appeared in Audis, Volkswagens, Bentleys, and Bugattis, with a W10 recently featured in the BMW M5. W18 engines were also constructed, though they remained limited to concept vehicles.

Even larger examples existed, such as the Duesenberg W24 employed in boat racing. Official information on these units is limited, so this overview centers on W engines installed in automobiles.

For the Passat: W8

One key benefit of W8 engines is their ability to fit more cylinders into a compact space. These units may be slightly wider than comparable V engines, yet they are notably shorter. The W8 combines two VR4 blocks on a single crankshaft, resulting in a compact package that Volkswagen installed in the Passat, whose engine bay was designed for a V6.

The engine reached a top speed of 155 miles per hour with 271 horsepower and 272 pound-feet of torque. While these figures were modest compared with contemporary V8s and the combined fuel economy stood at 18 mpg, the Passat earned praise for its ride quality. Still, the W8 model started near $38,000, equivalent to over $71,000 today, which limited its appeal.

Volkswagen produced the W8 Passat from 2001 until 2005. The following generation adopted a different engine orientation and switched to a VR6. Nevertheless, the W8 Passat continues to attract enthusiast interest and maintains a lasting legacy.

Widespread Use: W12

Among historic W12 engines, the Napier Lion stands out for its role in British military aircraft from the 1910s to the 1930s. It delivered 450 horsepower, the highest output of its era. A car equipped with two of these engines set a land-speed record of 369.7 miles per hour at Bonneville in 1939. That W12 featured three banks of four cylinders in a broad-arrow layout, differing from Volkswagen's modern W12, which uses four banks of three cylinders drawn from two VR6s.

The Audi A8, Volkswagen Phaeton and Touareg, multiple Bentley models including the Continental GT, Flying Spur, Batur, and Bentayga, plus Spyker's C12 La Turbie and Zagato all employed this W12 design. Bentley remained the final manufacturer to offer it, ending production in 2024 to prioritize a hybrid V8 aimed at greater power.

Built for Bugatti: W16

The modern W16 followed the same principle as other recent W engines but on a larger, more intricate scale, and it was developed exclusively for Bugatti. Planning began in 1997, with testing in 2001. Two eight-cylinder blocks joined at a 90-degree angle created four rows of four cylinders, keeping overall dimensions comparable to a V12.

The engine featured 64 valves and four turbochargers, producing nearly 1,500 horsepower at introduction. Later versions, such as the one in the Centodieci, reached almost 1,600 horsepower. Although such output exceeds typical street requirements, these vehicles emphasized luxury over everyday use. The Chiron W16 required 10 radiators and moved 60,000 liters of air plus 800 liters of coolant per minute to sustain its performance levels.

W16 engines remained confined to the Volkswagen Group, and future vehicles are unlikely to adopt them. Bugatti has phased out the Chiron's W16 in favor of a hybrid V16. Consequently, the 2024 Chiron Super Sport L'Ultime and 2025 Mistral represent the final mass-produced models with this engine.

Concept-Only: W18

W18 designs date at least to the 1930s, when the Japanese Navy developed three-bank units known as the Model 94 and YE2A. At least one version was completed and tested for aircraft use. After the war, Japan and other nations shifted focus to turbine engines.

Volkswagen also explored the W18. In 1997, CEO Ferdinand K. Piech sketched a concept combining three VR6 blocks for the Bugatti Veyron. Earlier W18 engines used three conventional inline banks of six cylinders each, yet all remained concept projects and never reached production.

The Bugatti EB118 concept of 1998 was the first to showcase a W18. It was followed in 1999 by an 18/3 Chiron concept at the Frankfurt Motor Show. A later W18 appeared in the Veyron 18/4 concept, though production Chirons and Veyrons ultimately received W16 engines.