Where’s my engine?
Have you ever wondered why things are the way they are in your car? For example, if you own a small car, the engine will most probably be in front of you, and power will go to the front wheels.india Updated: Aug 27, 2009 10:54 IST
Have you ever wondered why things are the way they are in your car? For example, if you own a small car, the engine will most probably be in front of you, and power will go to the front wheels.
If you own a GT, the engine will probably be in front of you, but the power will go to the rear wheels. If you own an SUV, the engine will send power to all four wheels.
If you own an exotic sports car, the engine will, in all probability, be behind you — all current Porsches with the exception of the Cayenne have their engine placed behind the passengers, as do the Ferrari F430 and the Lamborghini Gallardo. There are a number of reasons why these components are the way they are, and we’ll cover a few of those reasons in today’s column.
Most cars today have their engines in the nose, and they send their power to the front wheels. This allows for a bigger, more comfortable passenger cabin for the amount of space the entire car occupies on the outside — if the rear wheels were the ones getting the power, cabin space would be lost to house the propeller shaft.
The prop shaft is the same thing you’ve probably seen rotating at high speed on the underside of a truck; it goes from the engine to the centre of the rear axle. Since the prop shaft has to be straight, a ‘transmisson tunnel’ is required. If you’ve ever been the middle rear passenger in a taxi, you’ll know what we’re referring to. Transferring the power from the engine all the way to the rear of the car also means that some power is lost along the way.
Since the distance from the engine to the front wheels is shorter, less power is lost in a car that has its engine in the nose and drives the front wheels. If a front-wheel-drive car (FWD) is pushed too hard around a corner, the front of the car will usually give up first and drift towards the outside of the corner. Untrained instincts will have the driver lift off the throttle to slow the car down, and this will bring the car back in line.
However, if the same happens in a rear-wheel-drive (RWD) car, lifting off the throttle might not be the best thing to do. Even in low-grip situations like snow, rain or oil on the road, a FWD car is safer as a RWD car’s rear might fishtail or try to overtake the front under hard acceleration. This is why Audi manufactures either FWD or all-wheel-drive (AWD) cars, never RWD ones like BMW and Mercedes-Benz do.
Pickup trucks, vans and SUVs are usually RWD or AWD vehicles, since they have to haul more mass or need more grip than is needed under normal circumstances. RWD cars make for better-handling cars, but a powerful example might prove to be a handful for an ordinary driver. That is not to say that FWD cars can’t be exciting to drive, the Honda Civic Type R is a much-respected driver’s car, and the Seat Leon TDIs are managing to leave the BMWs eating their diesel fumes in the WTCC.
Exotic cars, formula racers and the fastest drag cars usually have engines behind the passenger compartment for different reasons. We’ll have a closer look at them sometime in the future.
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