Meanwhile, the majority of hatchbacks will go for the compact transverse option and are all the better for it. Cars that aren’t short of or don’t prioritise interior space - like saloons and sports cars - can easily accommodate a longitudinal setup to take advantage of a large, powerful engine. The argument of transverse vs longitudinal really boils down to the application. Front-engined, rear-engined, mid-engined, all-wheel drive, front and rear-wheel drive every setup will have driveshafts, diffs and transmissions in different places which produces a whole list of pros and cons for each. The current Honda NSX was originally set to use a transverse V6, before switching to a longitudinal setup.Īlthough we’ve only looked into front-engined setups, there is a huge range of orientations that can influence weight distribution, handling and power delivery. This is the very reason that most high performance cars opt for a longitudinally-mounted engine and drivetrain, with only select manufacturers like Noble, Toyota (with the MR2) and Lamborghini (the Miura) opting for a transverse engine mounted in a mid-engined position. The restricted horizontal space in a front-wheel drive, front-engined car means a large engine and transmission isn’t capable of fitting under the bonnet. Transverse engines are also restricted in terms of their displacement and potential power output. Low-friction differentials can also be implemented to try to equalise the torque transmission through each shaft. This means the two shafts can be of equal length, with slack being made up by the intermediate shaft.
This will allow for a more-balanced transmission of torque and was first used by Fiat in its front-wheel drive 127 and by Ford in the original Fiesta.Īnother method is equalising the shaft lengths by using an intermediate shaft from the transmission. The first is matching the torsional stiffness of the driveshafts by having one hollow and the other solid. This niggle has been combated by engineers using multiple ingenious methods. The longer shaft will naturally have a lesser torsional stiffness which means it transfers power less efficiently due to twisting more, forcing the car to steer slightly to the side that the longer driveshaft is on. This will expose the differences in torsional stiffness due to the differing lengths. The angle of incidence of the driveshafts from the differential will be different for either side. Torque steer is their greatest enemy, as this is induced by the difference in driveshaft length from the side-mounted transmission. Unfortunately, transverse engine layouts do have their limitations. The lack of drivetrain components needed also means that overall weight can be decreased and the manufacturing costs reduced, making these cars cheaper in general. In a FWD setup, this makes for maximum traction for the driven wheels which is obviously advantageous for acceleration and for tackling slippery surfaces.
In terms of driving dynamics, a front-mounted transverse engine places the majority of the car’s weight over the front wheels. The lack of a central tunnel needed to leave space for the transmission and a propshaft to a rear differential (a longitudinal RWD system) means that the floor can be much flatter to maximise passenger comfort. In city cars, a transverse engine allows for much more room in the interior to comfortably take five adults and some luggage.
The main reason they are so popular is the amount of space they free up elsewhere in the chassis. Transverse engines have become the norm in smaller mass-production cars, with a V6 normally being the largest engine layout that can be mounted in this way (although a transverse V8-powered cars do exist). Due to the transmission situating itself at one side of the engine bay, the driveshafts have to be different lengths to reach the wheels in comparison to a longitudinal setup that sits along the centreline of the car meaning the shafts are of equal length. As the need for bigger engines and more gears increased, transmissions moved to the side of engine blocks along with an off-centre differential for a simple insertion of the driveshafts through CV joints.