Say ‘V8’ to an automotive enthusiast, and images of many exotic and not-so-exotic but certainly iconic cars come to mind. Sachin Tendulkar’s Ferrari 360 Modena has a V8. Vin Diesel’s wheelie machine that is seen at the end of Fast and the Furious has a V8 engine.
Layout of choice
Just like straight-six engines were preferred up until a while ago, straight-eight engines were the layout of choice for automobiles when eight cylinders were used in cars. This was more due to the origins of the engine — straight-eight engines were not very wide, and their shape suited that of their application — aircraft. In the age before high-performance turbofans made their way onto military aircraft, piston-engined planes were the way to go.
Most popular straight-eight
Bentley has what is probably the most well-known straight-eight engined car, the Speed Eight. However, since the layout demanded the pistons be in a row, the engines ended up being up to four feet long!
To put that into perspective, if you ever tried to retrofit a four-foot straight-eight into a Tata Nano, you’d need to sit on top of it to drive it at all. And tow the fuel tank on a trailer behind. There were other problems with the straight-eight, too: the jolt that sent through the transmission when you got onto the throttle thanks to a long crankshaft wasn’t always pleasant. Then came the V8.
The Ferraris of the world may offer a purer driving experience, but I’ve always felt that I’d be happier listening to the offbeat blurb of a big-block V8 at idle. Both the Ferraris and the Mustang possess the same basic layout, that of eight cylinders arranged in two banks of four cylinders each. The benefits of the layout far outweigh the disadvantages of complexity caused by the two heads.
Managing cylinder power European sports cars that use V8 engines usually prefer firing a cylinder at a time, to spread out power more evenly. They also prefer to have large-diameter cylinders (‘big bore’ engines) with more than two valves per cylinder, and their stroke is short — which means that the distance the piston moves up and down is small. This makes them slightly weak at low revs, but much fun is to be had near the redline, both aurally and in amounts of thrust.
Today, Formula One cars possess an extreme example of this kind of engine. Muscle cars, on the other hand, are about torque. They use relatively rudimentary technology and they prefer to be ‘long-stroke’, which is not as economical on fuel as short-stroke engines are.
They also won’t rev as fast or high as a short stroke engine. American V8s used to prefer a cast iron block and fire two cylinders at a time. This gives them fearsome acceleration. A sophisticated thug of a car that you can buy in India is the 6.3-litre, 473 bhp Mercedes-Benz C63 AMG, whose engine would feel right at home on a drag strip.
Today’s manufacturers, who depended on ten and twelve-cylinder engines, are shifting to eight cylinders for better economy. The new BMW 7-series, Audi RS4 and just-launched-in-India R8 supercar have V8s, as do the Ford GT, Ferrari F430 Scuderia, Aston Martin V8 Vantage.
Today’s V8s could be oil-burners as well, as the VW Touareg will testify. Even sportscars are turning to diesel.
The next R8 won’t be the diesel V12 that is sending shivers down everyone’s spine. It’ll be a diesel V8 that will probably outperform the petrol V8.