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 

 Honda Civic
 Saturn S-Series
 Chevrolet Cobalt

 Front-Engine, Rear-Wheel-Drive 

 Fiat 124
 Dodge Challenger
 Pontiac Firebird
 Front-Engine, All-Wheel-Drive 

 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 
 Front-Mid-Engine, Rear-Wheel-Drive 

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

 Front-Mid-Engine, All-Wheel-Drive 

 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 

 Toyota MR2
 Ferrari F50
 Chevrolet Corvette (C8 models only)

 Rear-Mid-Engine, All-Wheel-Drive 

 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 DeLoreancenter|thumb|374x374px|Porsche is widely known for its faithful use of the rear-engine layout, which it has retained since the 1960s.

 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

Category:Automotive technologies