Automotive glossary starting with letter S


The sedan is the most common configuration of a modern automobile. Sedans usually have four doors, although the term can be used to describe a two-door body also. Most of them have a three-box configuration, but two-box bodies are also common, mostly in Europe.

Semi-elliptic multi-leaf springs

Usually found on trucks and sport utility vehicles, this type of springs consists of arched steel leafs that are stacked together horizontally to form the foundation of the rear suspension.

Sequential turbochargers

Sequential turbochargers were created from the need to decrease spooling lag. Two or sometimes more turbochargers are put to work in sequence. Usually, a smaller one begins working at low rpms and the other(s) at higher rpms, thus improving the power delivery throughout the power curve, not only above a certain number of revs.


Most part-time four-wheel drive systems in the past required their drivers to stop the vehicle and manually lock the front hubs in order to engage the all-wheel drive mode. Modern systems now have automatic front hubs locking, which translates into the ability to "shift-on-the-fly" from two-wheel drive to four-wheel drive mode.


Shocks are used in most suspension systems to compensate for heavy loads and also to restrict and stabilize the rebound and jounce movements. On racing cars or in the aftermarket tuning world, the shocks can be tuned to give the car better handling.

Short Long Arm suspension

The Short Long Arm (SLA) is a rather common type of suspension, which uses upper and lower control arms of different lengths in order to control wheel camber changes during suspension movement (jounce and rebound.)

Single overhead camshaft

Single Overhead Camshaft (SOHC) engines use one camshaft per each cylinder head to operate both the intake and the exhaust valves.


The term "skidplate" is referring to a protective plate(s) put under a vehicle to protect certain components that are vulnerable (transmission, oil pan, fuel tank etc.).

Speed-rated tires

Speed-rated tires are certified for safe use at higher speeds, after extensive testing by the manufacturer.

Sport Utility Vehicle

The Sport Utility Vehicle (SUV) is a type of passenger vehicle which combines the carrying capacity of a station wagon or minivan with features like an increased ground clearance and all-wheel drive. At first they were derived from truck platforms but most of them are now using unibody construction for a lighter weight and better fuel economy.

Station wagon

The station wagon (also known as a wagon, or an estate) is an automobile body configuration similar in design to a sedan with an extended cargo area.


The strut is a suspension element used mostly on unibody car configurations, that combines the shock absorber's main function with the ability to support sideway forces.


A subframe is a separate smaller frame usually attached to a monocoque (unibody) vehicle and is used in order to "keep" the engine and the transmission attached to the body of the car. Other types of subframes are used to attach the suspension to the vehicle's unitized structure.


The supercharger (also known as a blower in some countries) is used to compress air into the cylinders of an internal combustion engine. It works just like the turbocharger (increasing volumetric efficiency in the cylinders) except it's not powered by the exhaust gases but by belt or chain-drive from the engine's crankshaft.


The supermini (keicar in Japan and sub-compact in the US) is a class of automobiles that covers the smallest cars. They usually have a hatchback configuration and are designed specifically for city driving.

Supplemental Restraint System (airbag)

In order to reduce the driver/passenger's impact with hard parts of the interior of a vehicle in the event of a collision, the Supplemental Restraint System (SRS) causes an airbag to instantaneously inflate and supplement the seatbelt.

Suspension Travel

The term suspension travel is referring to the amount of vertical movement of a wheel along its vertical axis allowed by the suspension, from full jounce to full rebound.


The swaybar is a suspension element which comprises of a long torsion bar mounted between two wheels on the same axle. Also called an anti-roll bar or a stabilizer bar, it can restrict the body sway of the vehicle during cornering by transferring force and lateral movement from one wheel to the other.