All you need to know about the W engine configuration
The W engine can thank Volkswagen A.G., more commonly known as VAG, for becoming a recognized engine configuration. It shot to fame in 2001 with the introduction of the W12 engine used by Volkswagen, Audi, and Bentley. But what is a W engine, exactly? Like the more commonly available V engine, its name stems from its appearance. When viewed from the front, the engine is shaped like a W. Over the year, the W engine has been available in three-, six-, eight-, 12-, and 16-cylinder configurations. The biggest ever was a W30, used in a Sherman tank during WW II.
The W shape comes from three to four banks of cylinders using the same crankshaft, essentially forming a double V motor.
As mentioned earlier, the W motor gets its name from the cylinder bank arrangement resembling a W. There have been several examples over the years using three or four banks of cylinders. A little-known fact is that the three-bank layout was also called a broad arrow, because of the resemblance. Still, VAG is responsible for the mass production of the W-type engine. For the purposes of this article, we'll stick to the most commonly used examples, all of which come from VAG.
The most famous W engine configuration is the current W12, first introduced sans turbochargers in 2001. VW constructed this engine by using two VR6 engines mounted at a 72-degree angle. First used in a concept car, the original W12 was then used in the 2001 Audi A8. The specifications of the original were as follows:
There have been numerous attempts at building a W-type engine for cars over the years, most of them unsuccessful. The three most common versions are the W8, W12, and W16.
VW's W8 engine is no longer in production, but it has an interesting story behind it. This engine was supposed to be the big seller in VW's W engine range. In fact, while testing the concept, VW used a W8 and not a W12. The W8 made a short-lived appearance in the 2001 W8 Passat, which proved to be a poor contender in its segment.
The W12 is the most famous, used in Volkswagen, Audi, and Bentley products, as mentioned above, but it wasn't exactly stunning. The standard 4.2-liter V8 Audi S8 was faster. The concept only started gaining momentum once bolted into the front of the Bentley Continental GT. Bentley added two turbochargers, increasing the power to 552 hp and 479 lb-ft of torque.
The most stunning and ongoing application has been the W16 engine, used in both the Bugatti Veyron and Chiron. In its most potent current format, this engine develops 1,578 hp.
Interestingly, the W engine's coolest accomplishment is not a widely known fact. One of the first W-type engines was designed and developed by Anzani Motorcycles. It was also used in the first plane to fly across the English Channel successfully. From there, the W engine disappeared into obscurity, only popping up once in a while. It only really gained traction in 2001 with the introduction of the W8 and W12. But these engines would not exist if it weren't for another famous VW engine: the VR6. The VR6 engine is basically a mix of V6 and straight-six. It has two banks of cylinders like a V6, but it uses the same cylinder head. This meant the angle between the banks could be extremely narrow, which also means the engine is more compact. Volkswagen also made both four- and five-cylinder versions of this layout. VW never bothered building a W6 engine, because it already had both VR6 and standard V6 engines available.
Now, this is where it gets interesting. VW made the W8 by using two VR4 engines mounted on the same crankshaft. It was two engines within one larger engine - like Inception, but with powertrains, and less confusing. The degree between the banks on the VR engines was 15 degrees, and in W configuration, it went up to 72 degrees.
The next step was the W12, using two VR6 engines at the same 72-degree angle. As mentioned earlier, the power output wasn't incredibly mind-blowing, but there was still enough room left over for two turbochargers because of its compact size.
While the world was still getting used to the idea of the W engine, VAG was working on a W16 engine for Bugatti. VW used the VR engine layout to create another 15-degree VR8 and bolted two of them on the same crankshaft at a 90-degree angle - along with four turbochargers and a total of ten radiators. Because of the much wider angle between the VR8 banks, the engine resembled a V configuration, as you can see when you look at the exposed mid-mounted engine.
This engine proved to be so powerful that it's still in production today, powering the Chiron (as well as special-edition Bugattis like the Centodieci and Divo), albeit fettled to provide 1,500 hp+.
There have been a few cars, bikes, and planes with W engines, but the most common of them were VW-related.
These days the W12 is still used in high-end Bentleys like the Bentayga, Continental GT, and the Flying Spur. Bugatti still uses an updated version of the original W16 quad-turbo.
Over the years, there have been some notable, albeit limited, uses of the W12 engine.
You might not know the name Spyker, but it sporadically produces a new supercar once in a while. Its C12 Zagato was powered by the naturally-aspirated W12, as used in the Phaeton and Audi A8.
The most fantastic use of the W12 engine, to our eyes at least, was the 2005 W12 Touareg. This was just before the big financial crisis, so a massively overpowered SUV seemed like a good idea. VW ended up making 500, and the majority were sold in Saudi Arabia.
There is one significant advantage of the W configuration, and we already touched on it a few times. Because of the layout, the engine is more compact and lightweight. The best example is the Bugatti Chiron, which has 16 cylinders in a mid-engine arrangement. Its overall length is 178.9 inches, housing a 106.7-inch wheelbase. A Lamborghini Aventador S has an overall length of 188.9 inches and a 106.3-inch wheelbase. By using the W configuration, Bugatti can fit 16 cylinders within the same size wheelbase Lamborghini uses for a V12 engine.
On the downside, a W engine is more complex and harder to work on. From an enthusiast's perspective, a W12 isn't nearly as entertaining as a highly strung V12. We'll use the Lamborghini Aventador as an example again. The supercar has a naturally-aspirated V12 that produces 730 hp and 507 lb-ft of torque, and it spins to 8,500 rpm. The noise it makes is intoxicating. The W12 engine in the current Continental GT Speed, which is just a competitor in terms of the number of cylinders, produces more than 600 horses and 664 lb-ft of torque between 1,350 rpm and 6,000 rpm. That makes it less rev-happy, and while the W12 engine delivers a pleasing bassy thrum, it simply can't compete with a screaming V12 at 8,500 rpm.
Yes. Because of the layout, the engine is extraordinarily balanced and, therefore, smooth. That's the main reason why Bentley is the only manufacturer left using the W12 engine. It produces lots of torque low-down and remains refined through to 6,000 rpm. That makes it perfect for luxury barge applications.
Unfortunately future cars are unlikely to sport W12 engines. Two things are standing in the way. First is the electrification of cars, which is happening at a rapid rate. Bentley already offers a hybrid Bentayga, and the VAG group has made massive strides in electrification. The Porsche Taycan and Audi e-Tron GT are perfect examples. The second problem is the fact that there is a replacement for displacement. The VAG group's 4.0-liter twin-turbo V8 is widely used in its performance cars, and in some cases, is a much better fit. We'd have a V8 Continental GT over the W12 any day of the week.
Not all engines are equal - or at least, they come in different shapes and sizes, and, as a result, all of these have different capabilities and various applications. For example, a standard inline engine is very different from a rotary engine configuration, not just in design and structure, but also in advantages and disadvantages. While the former is simplistic in design and suitable for most mainstream cars, the latter offers immense power relative to its size and is more suited to sports cars.
Yes, but it will likely not be with the W16 engine. While we believe there will be some sort of swansong, the next Bugatti hypercar will have to be electric to match the performance of several upcoming electric hypercars. The current Bugatti Chiron was recently bested in a drag race by a Rimac Concept Two.