The Drivetrain of a car is a term which describes the engine setup or location and the means by which the engines power is directed to the road. This is usually made up of a abbreviation of the engine location and to which wheels the power is delivered.
FF describes a vehicle which is front-engined and front-wheel driven. Front-engined means that all or part of the car's engine is located in front of its front axle. This setup is very common in popular, low-powered road cars, such as the Ford Focus ST '06 or Toyota Yaris RS 1.5 (J) '00. The FF setup is generally regarded as good in low grip scenarios (though not as good as 4WD), but subject to understeer in normal conditions due to the steering wheels also delivering the power. High performance vehicles rarely use the FF layout because weight is transferred to the rear wheels under acceleration, while unloading the front wheels and sharply reducing their grip. Nevertheless, there are some racing cars with FF drivetrains in the Gran Turismo series, such as the Honda Gathers Drider CIVIC Race Car '98, Citroen Xsara Rally Car '99 and Audi TT Cup '16, with the Nissan GT-R LM NISMO '15 taking the crown as the most powerful FF car in the series, although it was plagued with hybrid system issues in real life due to the car's experimental design.
Cars of this drivetrain are required to enter FF Challenge events in the series.
FR describes a vehicle which is front-engined and rear-wheel driven. Historically, most cars had this type of drivetrain layout due to it being simpler to implement from an engineering point of view. However, in the late 20th century, FF became the preferred layout due to being easier and safer to drive for the average road user. FR however is still used for most modern sports/high-performance cars since it provides good controlled power, while leaving the front wheels free to steer the vehicle. During acceleration, weight is transferred to the rear wheels, which improves the efficiency of the driven wheels. Also, the position of the engine over the front wheels helps to transfer weight to them under braking, which improves traction when turning into a corner. FR cars however tend to sacrifice overall cornering performance for handling stability compared to MR cars, which is why not many supercars or dedicated racing cars feature an FR layout. Many high-powered sports cars and muscle cars feature a FR layout, such as the Mazda RX-7 and Ford Mustang. FR is the most popular drivetrain setup for drifting.
Cars of this drivetrain are required to enter FR Challenge events in the series.
MR describes a rear-wheel-drive car that has its engine placed between the front and rear axles of the car. Although there are real-world examples of mid-engined cars where the engine is placed in front of the passenger compartment (such as the Citroën DS, which has a mid-engined, front wheel drive or MF drivetrain), all the mid-engined cars that have appeared in the Gran Turismo series so far have the engine placed between the cockpit and rear axle. This shifts the car's weight balance towards the rear, creating a more responsive vehicle with higher cornering speeds, at the expense of being harder to control on the limit, requiring judicious steering and pedal control to avoid spinning. This makes it ideal for supercars and racing cars, where speed and performance takes precedence over ease of driving. Also, the high downforce of race vehicles helps to mitigate the instability issues associated with MR cars in higher-speed corners. Examples include the Acura NSX '91 and Toyota GT-One (TS020) '99, and all formula cars appearing in the series.
Cars of this drivetrain are required to enter MR Challenge events in the series.
4WD denotes any vehicle where all four wheels are powered by the engine, regardless of its placement. The four-wheel-drive setup is advantageous in that it improves control and traction, especially on loose surfaces and in wet weather. The disadvantages of four-wheel drive however are that it increases the overall mass of the car, as well as drivetrain inertia. This is why some dedicated road/circuit-racing cars based on 4WD models are converted to rear-wheel drive, such as the Subaru CUSCO SUBARU ADVAN IMPREZA '03 (although the 2008 specification retains the 4WD system due to changes in GT300 regulations permitting the drivetrain). Four-wheel-drive cars in the Gran Turismo series are typically geared towards off-road and rally driving, such as the Subaru IMPREZA Rally Car '99 or Lancia DELTA HF Integrale Rally Car '92. However, there are 4WD cars designed purely for on-road driving, such as the Nissan GT-R '07 (front engined), Lamborghini Murcielago LP640 '09 (mid engined), and RUF CTR2 '96 (rear engined). In addition, all Gr. B cars in Gran Turismo Sport has this drivetrain as a testament of their off-road nature.
Cars of this drivetrain are required to enter 4WD Challenge events in the series.
RR refers to a vehicle that features rear-wheel drive paired with an engine located behind the rear axle. While this is good for acceleration, this setup does not provide good grip in high speed corners and can lead to uncontrollable oversteer under braking. Not many examples of this exist in the Gran Turismo universe and there is no event strictly for the RR drivetrain. The original Fiat 500 and Volkswagen Beetle, as well as variants of the Porsche 911 such as the RUF CTR "Yellow Bird" '87 and the Porsche 911 GT3 RS (991) '16 are examples of this.
-- means that the drivetrain is classified, unknown, or does not fit into any of the above categories. Technically it is not a drivetrain, but is presented as one in the games. Examples include Chevrolet Chaparral 2X Vision Gran Turismo. As the Chaparral is not powered by the wheels, it is exempt from the "drivetrain" category.
In GT4, the Mazda Atenza Concept '01 was coded to have this "drivetrain"; this was later fixed in later games, revealing an FF drivetrain.
- ↑ Gran Turismo 2 driving guide