Automobile Basics F-G

Fastback

A car that has an unbroken curved line from the top of the roof to the rear bumper as opposed to a drop in the line for a near-vertical rear window. In a fastback design the rear window slope follows the unbroken roof line and is often at less than a 45 degree angle.

Feedback Fuel-Air-Ratio Control

A feature of a computer-controlled fuel system. By using a sensor to measure the oxygen content of the engine's exhaust, the system keeps the fuel-air ratio very close to the proportion for chemically perfect combustion. Such tight control of the fuel-air ratio is mandatory for the proper operation of three-way catalysts.

Fiberglass

A composite material that relies on small glass fibers for its strength. Fiberglass A very tough and durable plastic material with fibers running through the plastic. Used for race car bodies, many sports car bodies, and also enjoys considerable acceptance for passenger car bodies.

Final-Drive Ratio

The reduction ratio, found in the gearset of a drivetrain, that is furthest removed from the engine. Typically, the differential ratio.

Fixed or One Price Selling

Published fixed price displayed on a new vehicle eliminating need for negotiation. Fixture device for holding goods in process while working tools are in operation that does not contain any special arrangements for guiding the working tools.

Fleet sales

The purchase of vehicles by a business that meet a minimum requirement of units sold.

Floorpan

The largest and most important stamped metal part in a automobile's body. Usually assembled from several smaller stampings, the floorpan forms the floor and fixes the dimensions for most of the automobile's external and structural panels. It is also the foundation for many of the automobile's mechanical parts.

Fluid Coupling

Any device that transfers power through a fluid between its inputs and outputs. A fluid coupling basically consists of two fans in a sealed, oil-filled housing. The input fan churns the oil, and the churning oil in turn twirls the output fan. Such a coupling allows some speed difference between its input and output shafts.

Flywheel

A large, heavy iron or steel disc attached to the rear of an engine crankshaft in order to provide sufficient centrifugal force thereby smoothing its power flow.

Forecast

Prediction of future production or sales in the automotive industry.

Forging

A process that transforms solid metal into shapes of varying cross-sectional material thickness, often involving heating.

Four Valves Per Cylinder

A valvetrain with a total of four valves in the combustion chamber, typically two intakes and two exhausts. Compared to the more common two-valve-per-cylinder designs, a four-valve layout offers improved breathing and allows the spark plug to be located closer to center of the combustion chamber.

Four Wheel Drive (4WD)

A part time system that transfers engine power to all four wheels. 4WD systems usually lack a center differential that allows use in dry conditions. 4WD provides superior traction compared with front or rear-wheel drive.

Four Wheel Steering (4WS)

A mechanism that allows the rear wheels to steer. The steering angle is usually limited to 2-3 degrees. 4WS actively steers the rear wheels as well as the fronts to improve handling and maneuverability allowing more stable cornering.

Four-Stroke Cycle

An internal-combustion engine that requires two revolutions per cylinder or four piston strokes to achieve a power stroke internal stroke, compression stroke, power stroke, exhaust stroke. More efficient than the two-stroke-cycle engine. Also called Otto cycle.

Four-Wheel Drift

A somewhat imprecise term that describes a cornering situation in which all four tires are operating at large slip angles.

Frame

A bridge-like, structural base of a car that supports and positions the body and major mechanical items.

Front Wheel Drive (FWD)

The front wheels receive engine power. FWD provides more traction than rear-wheel drive(RWD) in poor road conditions because more weight is over the drive wheels. FWD also allows better use of interior space than RWD because all drivetrain components are concentrated in the front of the car.

Fuel Injection

On internal-combustion engines, a system that injects a precisely measured amount of fuel into the cylinder at exactly the right moment. Dispenses with the carburetor and increases engine efficiency. Fuel injection provides better metering of fuel and air than carburetors. This results in more power, improved fuel economy, and lower emissions. The simplest systems use single or dual injectors in a central chamber to supply all cylinders. More sophisticated systems use an injector at each cylinder to precisely meter fuel.Any system that meters fuel to an engine by measuring its needs and then regulating the fuel flow, by electronic or mechanical means, through a pump and injectors. Throttle-body injection locates the injector(s) centrally in the throttle-body housing, while port injection allocates at least one injector for each cylinder near its intake port.

G

The unit of measure for lateral acceleration, or "road-holding." One g is equivalent to 32.2 feet per second per second, the rate at which any object accelerates when dropped at sea level. If a car were cornering at 1.0 g: a figure that very few production cars are able to approach: the driver's body would be pushing equally hard against the side of the seat as against the bottom of it.

G.T./ Grand Touring

From the Italian Gran Turismo. A car combining sedan and sports car features in which engineering is the dominant feature. Combines excellent road handling qualities with relative comfort. Made in two- and four-seaters with the rear seats always cramped.

Gas Turbine

An internal-combustion rotating engine with one main moving part the rotor with pinwheel-like blades attached. Air is compressed by the first rows of blades and delivered to the combustion chambers, from which the exhaust is directed to pass the remaining blades and to generate the power. Power is extremely smooth due to the absence of explosions and reciprocating parts.

Gears

Wheels with meshing teeth to transmit power between rotating shafts. When the gear wheels are of different sizes, a change in speed ratio occurs. Gears are made of hard steel.

Gearset

A group of two or more gears used to transmit power.

Generator

A device that converts rotational energy to DC current. Generators were used in older cars to provide electrical energy for the vehicle.

Greenhouse

The portion of a automobile's body that rises above the beltline of the car.

Grey market

The grey market describes the purchase by intermediaries of product which is not supplied to them by the "authorized" distribution channel of the supplier. Thus, a warehouse club in Canada that sells a stereo bought in the U.S. or elsewhere from other than the manufacturer is supplying grey market goods. While grey market products are frequently the same as would be available from conventional channels, the grey market assumes responsibility for service or repair where the manufacturer declines this support.