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Stepper Motor

A motor that moves a specific amount of rotation with each voltage application.

Steptronic

A transmission strategy from BMW that allows clutchless shifting.

Stethoscope

A medical-type listening device used to detect and isolate noises within an engine while it is running.

STI

Self test input.

Stick

1. A camshaft. 2. A term used for stick shift.

Stick Shift

A manual transmission.

Stiffness

A measure of the dynamic elongation of a belt under tension.

Stinger

A slightly conical pipe used as an exhaust resonator to which individual headers feed, such as at the top of a high-performance Volkswagen Beetle engine.

Stirling Engine

A type of internal combustion engine where the piston is moved by changes in pressure of the alternately heated and cooled working gas.

STO

Self test output.

Stock

A factory-manufactured vehicle having standard design, parts and color.

Stock Car

1. A regular production vehicle. 2. A production vehicle modified to NASCAR standards for racing.

Stocker

1. A stock car. 2. A stock car that has been modified for racing.

Stoichiometric

A term often used for stoichiometric ratio.

Stoichiometric Ratio

The ideal air to fuel ratio of 14.7.

Stoichiometry

The state of having a stoichiometric air/fuel mixture.

Stoiciomitry

The science of providing the correct air / fuel ratio to the combustion chamber of a gasoline internal combustion engine.

Stoked

Excited or enthused.

Stone

Poor performing engine or vehicle.

Stoned

One who is intoxicated and should not be driving.