Powertrain layout

A powertrain layout is the way a vehicle is set up to use force to create motion. Usually, a powertrain layout is defined by the position of the engine and which of the wheels get power.

Powertrain layouts can usually be described in shorthand by their engine's position, followed by which wheels get power. For example, a Honda Civic would be a front-engine, front-wheel-drive car. On the other hand, a (pre-2003) Volkswagen Beetle would be rear-engine, rear-wheel-drive.

## Abbreviations 
In order to make discussion of these layouts simpler, they are often abbreviated as follows:

**Front-Engine, Front-Wheel-Drive**: FF

**Front-Engine, Rear-Wheel-Drive**: FR

**Front-Engine, All-Wheel-Drive**: F4

**Front-Mid-Engine, Front-Wheel-Drive**: FMF

**Front-Mid-Engine, Rear-Wheel-Drive**: FMR

**Front-Mid-Engine, All-Wheel-Drive**: FM4

**Rear-Mid-Engine, Front-Wheel-Drive**: MF

**Rear-Mid-Engine, Rear-Wheel-Drive**: MR

**Rear-Mid-Engine, All-Wheel-Drive**: M4

**Rear-Engine, Front-Wheel-Drive**: RF

**Rear-Engine, Rear-Wheel-Drive**: RR

**Rear-Engine, All-Wheel-Drive**: R4

Often, vehicles are designated solely by their driven wheels rather than their engine placements, making the following abbreviations:

**Front-Wheel-Drive**: FWD

**Rear-Wheel-Drive**: RWD

**All-Wheel-Drive**: AWD

## Front-Engine Layouts 
Vehicles that have their engine put ahead of the front axle of the car are called front-engine. While the term "front-engine" can also often be used as a way to say "front-engine" or "front-mid-engine", the two are not the same. The front-engine layout is the most common in the world since front-engine layouts tend to be easier to plan around, less costly of space inside the car, and less expensive to produce.

### Front-Engine, Front-Wheel-Drive 
FR is a common layout in small and cheap cars. This is because they tend to be less expensive to make and because they tend to let the car have more interior space. These vehicles are usually considered to be easier to drive in bad weather compared to FR vehicles. This is because they do not have the ability to oversteer (lose rear tire grip while keeping front tire grip) during acceleration that RWD vehicles do. These vehicles put out power through the front wheels only. Some examples of the FF layout are:

* Honda Civic
* Saturn S-Series
* Chevrolet Cobalt

### Front-Engine, Rear-Wheel-Drive 
FR layout is usually associated with classic sports cars. The engine is only used to power the rear wheels in this layout. Generally, FR is seen as being better-balanced and faster than FF, but with worse passenger comfort. This is because an accelerating car will tilt its weight backwards, giving the rear tires better grip while speeding up. In an FF layout, this means that grip goes away from the accelerating wheels and makes it more difficult to effectively use the engine's power. On the other hand, an FR layout car will gain grip on its tires being used to accelerate, so can use its engine's power more efficiently. Some examples of FR layout are:

* Fiat 124
* Dodge Challenger
* Pontiac Firebird
### Front-Engine, All-Wheel-Drive 
F4 layout is associated with off-road capable cars and luxury vehicles. The engine in these cars uses computers to use the engine's power on all four wheels, depending on which wheels can get traction at the given moment. FR advantages in acceleration can meet with the ease to drive of FF in the front-engine, all-wheel-drive layout (F4), alongside the traction advantage gained from using all four wheels for acceleration in low-grip environments. Some examples of the F4 layout are:

* Mitsubishi Lancer (Lancer Evolution models only)
* Subaru Impreza (although some models were FF only)
* Nissan Skyline (GT-R models only)

## Mid-Engine Layouts 
Vehicles with their engine between the front and rear wheels are classified as mid-engine. This can come in both a front-mid-engine and rear-mid-engine variety, with front-mid-engine being often misrepresented as being the same as front-engine.

## Front-Mid-Engine 
Generally, front-mid-engine vehicles are sports cars or are considered "sporty". They have their engine located in between the front axle and the driver, which gives the car a more even weight distribution than the regular front-engine layout would allow for.

### Front-Mid-Engine, Front-Wheel-Drive 
The FMF design is very uncommon, with the most notable example being the Citroën Traction Avant. It has also been used for the Renault 4. The layout is no longer considered modern. This is because FMF only existed as a solution to the problem of needing a conventional transmission (mounted length-ways) which was solved with the invention of the transaxle. When it was invented, the transaxle resolved the issue of lacking space for a front-wheel-drive vehicle's transmission, making the FMF layout no longer needed.
### Front-Mid-Engine, Rear-Wheel-Drive 
 to keep the weight evenly-distributed.]]Considered performance-oriented, though typically seen as less prestigious than rear-mid-engine sports cars, FMR layout is a common vehicle design when it comes to muscle cars, inexpensive sports cars, and performance vehicles generally. This layout helps to bring weight slightly closer to the driven rear wheels, helping to give the rear tires more grip as a result of the car's body shifting with acceleration. Many FMR vehicles only have two seats. Some examples of the FMR layout are:

* Saturn Sky
* Chevrolet Corvette (C2 to C7 generations)
* Honda S2000

### Front-Mid-Engine, All-Wheel-Drive 
The FM4 layout is an uncommon design for vehicles. Certain model year (1990-1992) Ford Cosworth RS500 models were FM4s. Combining the advantages of the F4 layout with the more balanced weight distribution of the FMR layout, the FM4 layout is both performance-oriented and relatively off-road capable.

## Rear-Mid-Engine 
Rear-mid-engine vehicles are usually dedicated sports cars, as they tend to have only two seats, aggressive handling, and less comfort than most other vehicle layouts. These tend to be, but are not necessarily always, rear-wheel-drive.
### Rear-Mid-Engine, Front-Wheel-Drive 
Rear-mid-engine, front-wheel-drive layout (MF) has never actually been attempted since to construct a vehicle in such a way would be impractical to drive. Doing so would likely result in poor handling, acceleration, and cabin space, as acceleration would both have weight present over the non-driven wheels and transfer weight away from the driven wheels, and cabin space would be limited by the need to use space behind passengers as an engine bay. No real world cars use this layout.

### Rear-Mid-Engine, Rear-Wheel-Drive 
The MR layout is often associated with exotic vehicles and supercars/hypercars (high performance, high cost vehicles with low practical use cases.) Brands like Ferrari and Lamborghini focus heavily on this layout, as does motorsport broadly (see Formula One). This layout places its weight distribution further back to assist rear traction when accelerating— even with significantly higher levels of power and torque than most sports car engines produce— and help to enhance turning dynamics. Some examples of the MR layout include:

* Toyota MR2
* Ferrari F50
* Chevrolet Corvette (C8 models only)

### Rear-Mid-Engine, All-Wheel-Drive 
The rear-mid-engine, all-wheel-drive layout (M4) is a more technologically advanced evolution of the MR layout. It combines the benefits to acceleration of the MR layout with the benefits to grip of an all-wheel-drive system, usually creating some of the highest-performing vehicles of their time. Some examples of the M4 layout include:

* Audi R8 (Type 4S only)
* Bugatti Veyron
* Lamborghini Diablo (VT 6.0 models only)

## Rear-Engine Layouts 
### Rear-Engine, Front-Wheel-Drive 
A mostly conceptual layout, RF exists in prototypes and thought experiments. The Dymaxion car is one of the few known examples of a realized RF vehicle, but it never really came to production. This layout would generally be considered impractical and mostly without use.

### Rear-Engine, Rear-Wheel-Drive 
RR is a vehicle architecture that places the engine behind the rear axle. Companies like VW and Porsche are known largely for their uses of this layout. It combines the benefits of a further back weight distribution helping for accelerating traction with the benefits to braking from theoretically being able to use both the front and rear brakes more effectively than in further frontward engine applications (due to the body of the car shifting forwards while decelerating, this means that cars with less weight already on the rear wheels will force their front brakes to do more work, as brakes cannot work better than the tires they are attempting to stop.)

This layout is sometimes criticized for being very punishing to drive. Porsche's 930 Turbo gained the status of being a "Widowmaker" for the perception of danger in its driving style. Some examples of the RR layout include:

* Volkswagen Beetle (Before 2003)
* Porsche 911 (Not all models are RR)
* DMC DeLorean

### Rear-Engine, All-Wheel-Drive 
The rear-mid-engine, all-wheel-drive layout (R4) is usually a modernization of the RR layout, using the traction advantage of all four wheels' contribution to help smooth out some of the less desirable driving traits of the traditional rear-engine, rear-wheel drive configuration. While not necessarily common, many cars do use an R4 layout and have for decades. A prominent example is the Porsche 964, a form of Porsche 911 optioned with an all-wheel drive system. In the modern day, the Porsche 911 can be bought with all-wheel-drive as an option, but can also be bought with rear-wheel-drive.

## References