POWERTRAIN
a very important role in the dynamics of the vehicle, particularly the weight distribution and the overall moment of inertia. For everyday utilitarian vehicles, such as city cars and family hatchback models, the preferred solution is a front engine with front- wheel drive, which leaves the bulk of the space available for passengers and their luggage. For high-performance sportscars, a more focused approach sacrifices some of this convenience to deliver a more engaging driving experience and accepts the impact on passenger space, cooling system layout and general packaging efficiency. Placing the heaviest single
assembly, the engine, close to the centre of the car makes it easier to achieve a more even weight distribution across the front and rear wheels, giving more neutral handling, particularly during enthusiastic
Multi-layer heat shields made from a sandwich of insulation between two thin stainless steel layers
cornering on undulating roads. Because centralising the mass of the vehicle reduces its polar moment of inertia, the car responds faster to driver inputs without resorting to steering geometry that could feel ‘edgy’ or ‘nervous’ during everyday driving. Sharing the
❝ The choice of engine location plays a very important role in the dynamics of the vehicle...
weight more equally between the four corners of the vehicle also reduces the trade-offs in suspension tuning between handling and ride quality. For a road-going sportscar, all these characteristics combine to provide a more thrilling, yet safer and more comfortable driving experience. Compared to a front engine/rear
drive arrangement, the mid-engine layout improves traction under hard acceleration and benefits stability under braking and when changing direction. Today’s electronic systems such as ABS and skid control have less work to do, so can perform better, increasing safety margins. Moving the engine to a central position also frees up useful space at the front of the vehicle which can be used for the energy-absorbing crumple zones that make the vehicle safer in a frontal impact.
PICKING UP THE TAB The compelling benefits of a mid-engine design must, inevitably, be paid for in other ways. The main disadvantage is reduced passenger space, which
explains why most mid- engined vehicles are two- seaters. The second issue to arise is cooling; radiators
must either be front-mounted and connected via suitable pipework, or mid-mounted with large ducts and vents to ensure adequate airflow. Either of these options can be incorporated readily
into a sportscar as part of the overall styling but much less so in a more practical vehicle.
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