Tuesday, October 5, 2010

Sports car

The drive train and engine layout significantly influences the handling characteristics of an automobile, and is crucially important in the design of a sports car.
The front-engine, rear-wheel drive layout (FR) is common to sports cars of any era and has survived longer in sports cars than in mainstream automobiles. Examples include the Caterham 7, Mazda MX-5, and the Chevrolet Corvette. More specifically, many such sports cars have a FMR layout, with the centre of mass of the engine between the front axle and the firewall.
In search of improved handling and weight distribution, other layouts are sometimes used. The RMR layout is commonly found only in sports cars—the motor is centre-mounted in the chassis (closer to and behind the driver), and powers only the rear wheels. Some high-performance sports car manufacturers, such as Ferrari and Lamborghini prefer this layout.
Porsche is one of the few remaining manufacturers using the rear-engine, rear-wheel drive layout (RR). The motor's distributed weight across the wheels, in a Porsche 911, provides excellent traction, but the significant mass behind the rear wheels makes it more prone to oversteer in some situations. Porsche has continuously refined the design and in recent years added electronic driving aids (i.e. computerised traction-stability control) to counteract these inherent design shortcomings.
Some sport cars have used the front-engine, front-wheel drive layout (FF), e.g. Fiat Barchetta, Saab Sonett and Berkeley cars. This layout is advantageous for small, light, lower power sports cars, as it avoids the extra weight, increased transmission power loss, and packaging problems of a long driveshaft and longitudinal engine of FR vehicles. Yet, its conservative handling effect, particularly understeer, and the fact that many drivers believe rear wheel drive is a more desirable layout for a sports car make this layout atypical to high-performance sports cars. The FF layout, however, is common in sport compacts and hot hatches, and cars in general (excepting sports cars).
Before the 1980s few sports cars used four-wheel drive, which had traditionally added a lot of weight. Although not a sports car, the Audi Quattro proved its worth in rallying. With its improvement in traction, particularly in adverse weather conditions, four-wheel drive is no longer uncommon in high-powered sports cars, e.g. Porsche, Lamborghini, and the Bugatti Veyron.


arieEmas said...

nice blog....

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