Drivetrains

All cars have drive trains. They are the channel through which engine power travels to the drive wheels. The three most common drive train layouts are: FF (Front engine, front wheel drive), FR (Front engine, Rear wheel drive), AWD (All wheel drive). Of these, the most common is FF. In FF layouts, the engine is usually small and compact so that it can be mounted transversely (which is sideways versus longways). Likewise, FF layouts usually have 4, 5 or 6 cylinder engines which many cars today are equipped with.

FF; Front Engine, Front Wheel Drive: The engine is in front with the drive wheels there too. FF is preferred by most manufacturers because it is cheapest to mass produce, and is relatively simple. The majority of FF layouts have the engine sideways, or transversely mounted in order to save space and weight. It used a torque converter, transaxle and final drive instead of a driveline. These work with the differential and the driveshafts to spin the front wheels with the engine, providing torque. Since the weight of the engine sits over the drive wheels with this layout, traction on snow/ice is improved over FR, but not AWD.

The Honda Accord is FF with an I4 or V6 engine transversely mounted

The Toyota Camry is FF, with a inline four or V6 engine, like the Honda Accord Even this Italian sports car, the Alfa Romeo GTV, is FF with a sporty 3.0 liter V6 engine, transversely mounted

FR; Front Engine, Rear Wheel Drive: This is the traditional layout of all old cars (before 1980s), most sports cars/performance cars, and luxury cars. It is different because it has a driveshaft going back to the rear wheels, that the engine transmits torque across. There is also the differential which transmits the twisting action of the driveshaft to rotation that spins the rear wheels. With FR, the engine is mounted longways, or longitudinally. This layout is used by performance cars because it is able to cope with tremendous amounts of torque and horsepower from powerful engines, luxury cars because of smoother ride quality (the turning wheels do not spin from torque like in FF, creating less vibration). All trucks use FR again because of being able to handle torque, as much more torque is needed to pull heavy loads. Vehicles with 4x4 use rear wheel drive when not using the other two wheels, like Jeeps or pickup trucks. It is less common now but manufacturers like BMW, Mercedes-Benz, Infiniti, Lexus and even Cadillac still use FR in many of their cars. But in slippery conditions, it is harder to keep traction with FR because there isn't much weight over the rear wheels.

The BMW 5 series is a German executive car with FR

                     The Mercedes-Benz S-Class is a very luxurious car, and is FR

All Wheel Drive (AWD/4WD): This setup either has the engine in the front, rear, or mid part of the car. And it is linked to all four wheels with 3 differentials: front, middle, and rear. This setup gains a lot of torque and traction because of all four wheels spinning with the engine. Some performance cars, SUV s, and Off-Road vehicles use 4WD. Some vehicles can switch between using two wheels, or four wheels with controls. It has excellent traction in wet or slippery conditions. It is complex and expensive to make though, yet many manufacturers make models that have it or offer it as an extra price option.

The Subaru Impreza is a performance car with 4WD layout

The Audi A3 Sport Hatchback is equipped with 4WD

The Lexus RX 350 is an 4WD SUV

Rear Engine, Rear Wheel Drive (RR): It is a drivetrain with the engine mounted in the back, and the drive wheels right underneath it. It isn't used much anymore, but famous cars to use it are: the old Type 1 Volkswagen Beetle (made from 1938-2003), the Porsche 911 (from 1964-present) and also the DeLorean DMC-12 (the Back to the Future time machine!). Many RR cars have flat, horizontally opposed engines (boxer) because they take up less space and have even weight distribution due to the positioning. Since the weight of the engine is over the drive wheels like an FF layout, it has better traction and handling around corners than FR. Generally, the more weight that is over the drive wheels, the better traction you will have (to a limit, where the weight would overload the engine and the car wouldn't be able to move).

The Volkswagen Type 1 (old Beetle) was RR with a flat-four boxer engine  The Porsche 911 is also RR, with a flat-six cylinder boxermotor

MR (Rear Mid-Engine, Rear Wheel Drive): With this, the engine is located near the back of the car, but ahead of the rear axle, with the drive wheels being the back ones. This is an uncommon layout, generally only used in super sports cars and race cars, due to optimal weight distribution, but with space for a larger engine, unlike RR. They are generally small and lightweight cars because if the car is too large, then MR can make it "tail-heavy" and likely to spin out and lose traction. The weight over the rear end is higher than over the front end, which makes braking more effective but also makes the car more difficult to steer (understeer) because since the front end is lighter, it lifts off of the ground. To counteract this, front spoilers (basically wings that cause the airflow to push down on the wheels, giving better cornering) are often added underneath the car or on the front of it. It has a differential and also driveshafts attached to the engine that spin the rear wheels.

The Ferrari Enzo is a supercar capable of driving at over 200 mph, and it has an MR layout The Lamborghini Diablo is another 200 mph supercar that has MR layout This Formula 1 car has an MR layout, for improved braking and for weight distribution. The wing on the front is to keep the front end down firmly on the track so cornering is sharp.

ALL IMAGES ARE FOR DEMONSTRATION AND ARE NOT MINE