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Anti-lock Braking System (ABS)
Braking systems which sense wheel rotation and automatically "pump" the brakes for the driver in emergency braking conditions. The pumping and the prevention of wheel lockup allow the driver to retain steering capabilities during the braking emergency. Any Fool purchasing a vehicle with such a system would be well advised to insist on the dealership demonstrating the proper use and maintenance of it. Most of these systems work when the driver applies heavy, constant braking pressure, and do not work properly if the driver "pumps" the brakes as he may have been previously taught.

Air Brakes
Usually found on heavy-duty trucks, using compressed air to operate.

Air Injection
A method for reducing exhaust emissions. The injection of fresh air into the engine exhaust ports, combined with the high heat present in the exhaust manifold, causes the burning up of leftover fuel vapors.

The wind resistance of a vehicle's design elements. Aerodynamic vehicles claim to offer increased performance and reduced wind noise while moving.

Alloy Wheels
Any non-steel road wheel. Mostly aluminum, but technically a mixture of two or more metals.

Anti-Roll Bar
A suspension component. A steel rod or tube that connects the left and right suspension members to resist roll or swaying of the vehicle. Improves handling.

Vertical roof support between the windshield and front edge of the front side window.

Aspect Ratio
The ratio between the width and sidewall (or height) of the tyre. Tyres with lower aspect ratios, usually found on sports models, provide superior handling but a harsher ride.

Automatic Transmission (AT)
A system that varies the power and torque to a drive train without the use of a foot-operated clutch.

Automatic Temperature Control (ATC)
Automatically controls a vehicle's heating and cooling systems, maintaining a temperature preset by the occupant.

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Vertical metal roof support between front and rear side windows on the side of the vehicle.

Back Pressure
The pressure produced by restrictions in an exhaust system. Back pressure affects the rate at which exhaust gases are extracted from the cylinders.

Bench Seats
Full-length seat that runs along the rear width of the car cabin so that more than two passengers can sit there.

Body Style
The type of exterior shell or shape to a vehicle (hatchback, sedan, coupe, etc.).

Diameter of an individual engine cylinder. Relates to that of the piston stoke length, both being given in millimeters, e.g. - 77.0/85.5mm.

Bucket Seats
Individual driver or passenger seats, that enclose a person by means of depth curvature an side lips. Usually found in customized a sporting cars.

A small car made from light wood a metal, with no mechanical content other than a steering mechanism plus 2 axels.

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The vertical metal roof support between the side edge of the rear windshield (also called the backlight) and the rear edge of the rear window.

The interior people-space within a car. For a truck it's called a Cab. The 'Greenhouse' is a term used in automotive circles to describe all of the windows enclosing the passenger compartment.

A two-door small open car with a hand- retractable roof, being either a rag (cloth) top or hard top. Seating 4 usually, may also think as convertible or coupe.

Carbon Fibre
This is an ultra-light, but extremely strong material that has been used to manufacturer vehicle parts for road a racing cars. It was introduced to the World of Formula 1 racing in the 1970's in the form of large but light wings.

Central Locking System
On a vehicle with power door locks, the system locks or unlocks all doors at one time.

This is the part of the car in which the driver sits and to which the engine and suspension are attached. It is the base of a car.

Climate-Control System
The non-technical term for the heating, ventilation and air-conditioning system (HVAC). Most current vehicles have all three - heating, defrost, and AC.

This drive train component is found between the engine and the transmission. It acts as a coupling device which is used to engage and disengage the transmission from the engine when shifting gears. It is necessary to do this joining and detaching because the engine is turning at a relatively high rate (thousands of revolutions per minute), and attempting to alter a gear ratio at this point could send various bits of transmission shrapnel careening about the occupant compartment.

Club seat
The rear seat in a coupe.

Coil Spring
A heavy-duty, spiraled metal component of the suspension system which forms a dynamic connection between the body of an automobile and its chassis.

Compression Ratio
The ratio of the volume within an engine cylinder when the piston is at the bottom of its stroke, compared to the volume in the cylinder when the piston is at the top of its stroke. The higher the ratio, the more compression during combustion and the more powerful the engine. e.g. - 8:3:1

A medium-large sized car seating up to 5 people having possibly 4 doors, with a top that can be either lowered or removed.

Generally, a two-door car with close-coupled passenger compartment.

Cruise Control
A device that, when set by the driver, will hold the car at the chosen speed.

Cruiser skirts
Optional accessory similar in function to fender skirts but are normally longer, fit on the outside of the body of the car, and are most often used in customization work.

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A device which reduces vibration.

Daytime Running Lights (DRL)
These lights come on whenever the vehicle is turned on; they make the vehicle more visible to other drivers. Standard equipment on many high end vehicles.

This may refer to the unit found between the front driver and passenger seat that contains the automatic transmission shifter, cupholders and a storage compartment. But it can also refer to the section of the instrument panel that includes the controls for the sound system and climate-control system, particularly if the panel flows down the center of the vehicle and includes the automatic-transmission shifter.

A mechanical gearbox or fluid coupling that allows wheels to rotate at different speeds. Usually located on an axle, it allows the outside wheels to turn faster than the inside wheels during cornering. Four-wheel-drive and all-wheel drive vehicles have two differentials, one for the rear axle and one for the front. all-wheel drive vehicles also may have a third or center differential on the drive shaft that runs between the front and rear axles.

The volume displaced by an engine's cylinders. Formerly measured in cubic inches, it is now more commonly expressed in liters.

The air pressure applied to the surface of a car at high speed, by means of aerodynamic body details, thus improving its traction, as airflow tries to lift the car.

Double Wishbone Suspension
A type of independent suspension in which the upper and lower support pieces, or members, look somewhat like a wishbone.

Drive Range
The distance an electric vehicle can drive without re-charging its batteries.

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Electronic Brake Distribution is a component used with ABS an usually a brake assist mechanism, for small powerful cars, like the new Mini of 1998.

Electronic Mufflers
In an electronic muffler system, sensors and microphones in the exhaust system sense the pattern of exhaust pressure waves. This information is sent to an on-board computer that controls loudspeakers in the muffler. The computer operates the loudspeakers to generate sound waves that oppose and cancel the original exhaust sound waves produced by the engine.

Electronic Stabilization Program
(ESP) increases vehicle control in situations near the vehicle's limits. It reduces the risk of skidding and helps to keep the vehicle on course. ESP recognizes the course desired and the car's reactions. Through brake application at individual wheels, it generates one-sided forces which help the car to move in the desired direction. The ESP program uses other driving aids and is permanently engaged.

Electronic Control Module (ECM)
Electronic Control Module. The master computer responsible for interpreting electrical signals sent by engine sensors and for activating automated engine components and processes accordingly in order to produce optimum performance.

Electronic Ignition
A system which uses an electronic unit as opposed to an older mechanical style distributor with points (contacts) to control the timing and firing of spark plugs.

Engine layout
The position it sits within the chassis, the cylinder amount, their arrangement, the CC total, plus any extra add-ons.

Exhaust Manifold
A cast set of pipes or passages through which exhaust gases exit the engine cylinders on their way into the exhaust system.

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Factory standard
The basic design and options that make up the packaging of an entry-level vehicle.

A body panel that lies below either side of the bonnet, between the front bumper and front-most door edge, encompassing the wheel space in-between, [2 off].

Four-Wheel Drive (4WD)
A transfer case distributes power to both axles in order to drive all four wheels. Sometimes called All-Wheel-Drive.

Four-Wheel Steering
Vehicle on which all four wheels turn when the driver turns the steering wheel. The rear wheels turn at a smaller angle than the front wheels.

Fog lights
Two special headlights designed for cutting through foggy conditions along the road ahead.

Front Wheel Drive
The front wheels are the ones that are being powered by the engine/transmission, and the rear wheels just follow along. Generally speaking, these cars are more fuel-efficient than their rear-wheel drive counterparts, and they operate more easily in snow, but they are more expensive to build and maintain.

Fuel Injection System
Injects fuel into the engine's cylinders with electronic control to time and meter the fuel flow.

Fuel System
These systems are vast and countless, but today's basic systems divide into two fundamental groups: carburetor systems and fuel Injection systems. Carburetor systems work by allowing the vacuum created by the engine in the intake stroke to pull fuel and air into the engine. Fuel Injection systems are more common these days. Sensors and computer controls monitor various engine speeds, air flows and throttle positions, and then tell the system what to do. A fuel pump is used to transfer the gasoline from the fuel tank to the injector (which is kind of like a spray nozzle).

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Gas-Charged Shocks
Also called gas-filled shocks. They are shock absorbers filled with a low-pressure gas to smooth the vehicle's ride during up-and-down movement.

Gear Ratio
The ratio of teeth counts between meshing gears.

A metallic enclosure containing several cogs, each one affecting the effort in which the car moves. Each cog/gear has a different mph ratio per 1000rpm. Overall control maybe manual via the gear stick, automatic, or semi via a hand paddle.

An opening in the front of the vehicle that allows air to reach the radiator.

Gross Vehicle Weight
The actual weight of the vehicle plus the maximum load it is designed to carry.Or the kerb weight of the vehicle plus the maximum load it is designed to carry.

Ground Clearance
The distance between the ground and the lowest point of the vehicle chassis (usually the axle). A vehicle can drive over any object shorter than its minimum ground clearance.

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A car designed to resemble a convertible in looks and feel but without a removable top. Hardtops do not have the fixed post between the side windows.

Halogen bulb
A special headlight form whose brightness power is greater than standard bulbs, though they cost more an last shorter.

A passenger car with a full-height rear door that includes a rear window. Usually has a rear folding seat. Also called a 'Compact'.

Head Room
The distance from the top of an occupant's head to the headliner.

Horsepower (hp, bhp)
Abbreviated as hp, as in 200-hp engine, or bhp (brake horsepower or net horsepower) to designate power produced by an engine. In general, the higher the horsepower, the higher the vehicle's top speed. One horsepower is the power needed to lift a 550-pound weight one foot in one second.

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I-Beam Suspension
A suspension beam under the car that supports the body in the shape of a capital I.

Idle Speed
The speed of the engine at minimum throttle and the engine in neutral.

Ignition System
The system responsible for generating and distributing the electrical spark needed to ignite fuel in the cylinders and for altering the frequency (timing) of that spark in relation to changes in engine speed.

Intake Manifold
A cast set of pipes or passages through which fuel or air is directed into the cylinders.

Independent Suspension
A suspension design that lets each wheel move up and down independently of the others. A vehicle can have two-wheel or four-wheel independent suspension; sportier models have four-wheel independent suspension. See also Multi-Link Suspension, Live Axle.

In-Line Engine
Cylinders are arranged side by side in a row and in a single bank. Most four-cylinder and some six-cylinder engines are in-line engines. In V-6, V-8 or V-12 engines, the cylinders are divided into two banks, each of which is angled away from the other in a 'V' pattern.

An electronic safety feature that prevents a car from being illegally driven away.

Interior Payload
The amount of space or material that can be carried inside the vehicle.

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Jump start
To transfer electrical power from one car battery to another to enable the cars ignition system to startup, using jump leads.

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Keyless Entry
A system for locking and unlocking doors of a vehicle with a central locking system without using the key. Usually, the user controls the locks by pressing a button on a remote key-fob transmitter. Some vehicles have electronic combination locks on the doors near the handle.

Kilometers Per Liter (KMPL)
It is a mileage of the car, which shows how far car can travel in a liter of fuel. Generally known as Fuel Average of a car.

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Lap-and-Shoulder Belt
A safety belt that secures the driver and/or passenger in the seat with a continuous web of material which fits across the lap and crosses the upper body. It keeps the occupant from jerking forward in the event of a crash. Also called three-way belt, three-point belt, or three-point safety harness, or just a seat belt.

Leaf Spring
Suspension spring made up of several thin, curved, hardened-steel or composite-material plates attached at the ends to the vehicle underbody. The curved shape of the plates allows them to flex and absorb bumps.

Leg Room
With the front seat adjusted all the way back, the distance from the accelerator pedal's heel point to the back of the front seat cushion.

Lift Gate
The rear opening on a hatchback. Called a tailgate, or hatch door.

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M+S Rating
A tyre rating which indicates a tyre designed to perform well in mud and snow.

MacPherson Strut
A MacPherson strut is a unit that includes a damper or shock absorber cartridge inside a large, long metal spring. MacPherson struts are used over the front wheels of most front-drive cars. Replacement of MacPherson strut cartridges requires a spring compressor.

Manual Transmission (MT)
A transmission that varies the power and torque through a foot pedal controlled clutch and a floor-mounted or steering-shaft-mounted gear selection lever.

Max power
Two figure totals given in brake-horse-power by engine revs per minute. [bhp x rpm].

Max torque
The weight of force per foot, given in pounds, and the rpm level, e.g. 100 lb ft at 1000 rpm.

A chamber in the engine exhaust system used to suppress exhaust noise and smooth exhaust pulsations. Also referred to as a "silencer".

A multi-person vehicle, like a windowed van with several seats. Similar to a mini-bus but with modcons and for private use.

Multi-Link Suspension
Independent suspension controlled with several link arms that restrict undesired motion of the suspension for a smoother ride and more precise handling.

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A mixture of nitric acid and methane which is used to fuel Top Fuel Dragsters and Hotrods; is also called nitro or top fuel.

A small frontal body section of a car which extends beyond the bonnet line, typically slanting downwards. The narrower version used on Formula cars is called a shark-nose. 'Nosed' refers to the process of raising a small peak in the center of the bonnet of a car, usually as part of a customized design.

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Indicates the number of miles a vehicle has been driven, and is also called a Milometer. Odometer Rollover occurs when the vehicle's mileage exceeds the mechanical limits of the odometer - usually 99,999 kilometers.

Off roader
A wheeled road vehicle whose design allows it to move across rugged terrain with greater ease than standard vehicles. Also known as SUV.

Over steer
Occurs when the rear tyres lose adhesion under cornering. Over steer can lead to a spin if the driver doesn't reduce acceleration.

A transmission gear with a ratio below 1:1, which improves fuel economy by reducing engine revolutions per minute at highway speeds. On a five-speed manual transmission, the fourth and fifth gears are overdrive. On a four-speed automatic transmission, the fourth gear is overdrive. When an overdrive gear set is engaged, the output shaft turns at a higher rate than the input shaft, reducing engine revolutions at cruising or highway speeds.

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Passive Restraint
A device or structure that automatically helps restrains vehicle occupants in an impact. This includes airbags, belt pre-tensioners, padded knee bolsters, and shoulder belts that are motorized, or attached to the door.

Package Shelf
The ledge between the rear seat and the backlight (or rear windshield). The name is misleading because it's a bad idea to put anything on the package shelf. However, it often contains the sound system's rear speakers and, on some vehicles, center brake light. Sometimes also called the parcel tray.

The type of light-duty truck with an open cargo bed behind a closed cab.

Power Steering
A steering system that uses a separate motor or engine power to reduce the effort necessary to turn the front wheels.

Power Steering Fluid
Many power steering systems use hydraulic power. These systems use a power steering pump driven by a belt from the crankshaft. The pump moves fluid under pressure through hoses to the steering gear. The pressure is used in the steering gear to reduce steering effort. A reservoir for fluid is attached to the rear of the pump.

Power-to-Weight Ratio
The maximum power output of the vehicle per unit mass. The higher the ratio, the more powerful the vehicle. In comparing several vehicles, this can be a better measurement than engine horsepower or torque because it considers the weight variable. In other words, a car that seems to have a powerful engine but is also heavy may have less get-up-and-go than a vehicle that has a similar or less powerful engine but also weighs less. Lotus are the best exponents of this. Given in a BHP per tonne value.

Power train
The combination of engine and transmission.

A device that rapidly yanks in shoulder-belt slack when a crash sensor detects an impact. So far, pre-tensioners are still found on more expensive models. By pulling in belt slack within milliseconds of an impact, pre-tensioners help reduce chest and head injury by restricting occupant motion and preventing the occupant from hitting the belt.

Projector-Beam Headlights
A headlight that uses a spherical reflector to tightly control the light beam. The bulb or light source directs the light inward, toward the reflector at the back of the headlight assembly, which then projects it forward from the vehicle. These lights are more powerful, accurate and expensive than standard sealed-beam and halogen headlights, and are generally found on sport and luxury models.

Acronym for pounds per square inch. A pressure measurement used in tyre inflation and turbocharger boost.

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Rack and Pinion Steering
The steering wheel is connected to a pinion gear that meshes with a toothed bar, also called a rack or linear gear. As the pinion turns, the rack moves side to side, moving the steering linkage and causing the front wheels to turn left or right. The ends of the rack are linked to the steering wheel with tie rods.

Rag Top/Soft-top
A convertible with a soft top, usually made from canvas or a polymer.

Rear-Wheel Drive (RWD)
The drive train in which power is applied through the rear wheels only.

A car having a mechanically retractable hardtop.

Revolutions Per Minute (RPM)
Describes at which speed the engine crankshaft is turning.

The outer edge of a bare wheel. A hub-cap sometimes sits within this.

Roll cage
A protective steel cage to prevent driver injury during a rollover.

Rumble seat
Fold-up seat in the rear of a car.

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A fixed-roof car with at least four doors and an extended boot.

Sequential Fuel Injection
Similar to multi-port fuel injection, but the injectors spray fuel into the individual intake ports exactly at the beginning of each cylinder's intake cycle. The precise fuel control provides better engine performance.

Shift Interlock
On a vehicle with automatic transmission, a safety device that prevents the driver from shifting out of park unless the brake pedal is depressed.

Shock absorber
A device that converts motion into heat, usually by forcing oil through small internal passages in a tubular housing. Used primarily to dampen suspension oscillations, shock absorbers respond to motion; their effects, therefore, are most obvious in transient maneuvers.

Side Airbag
An inflatable cushion that fills the space between the door and the occupant to prevent head, torso and pelvis injuries when a vehicle is hit from the side. Side airbags may be stored in the door-trim panel or the outboard side of the seat; they may protect the hip and torso only or also protect the head. A new design, called an inflatable tubular restraint, is stored in the edge of the roof headliner and attached at the base of the A-pillar at the front end and above the doors along the roofline at the other. The device inflates into a somewhat stiff tube that prevents the occupant's head from hitting the side pillar or the window.

Single Overhead Cam (SOHC)
An engine with a single overhead cam generally has one intake and one exhaust valve per cylinder; the single cam opens and closes both valves. See also Overhead Cam and Dual Overhead Cam.

Space frame
A particular kind of tube frame that consists exclusively of relatively short, small-diameter tubes. The tubes are welded together in a configuration that loads them primarily in tension and compression.

An instrument dial above the steering wheel which informs the driver of the current speed, in KPH and/or MPH.

Sport Utility Vehicle (SUV)
Refers to a style of truck which has a square passenger cabin and hatchback, and may be equipped with two- or four-wheel drive.

Sports Car
A body type designation. Generally a small, powerful car seating only two people.

An aerodynamic device that changes the direction of airflow in order to reduce lift or aerodynamic drag and/or improve engine cooling.

Straight-line tracking
The ability of a car to resist road irregularities and run in a straight line without steering corrections.

Station Wagon
A two- or four-door passenger car with a cargo area that extends all the way to the rear bumper. A model variant derived from an extension of a popular saloon model, also termed an estate version.

A single, self contained pivoting suspension unit that integrates a coil spring with a shock absorber. Struts are used on front wheel drive automobiles. A suspension element in which a reinforced shock absorber is used as one of the wheel's locating members, typically by solidly bolting the wheel hub to the bottom end of the strut.

The up-and-down distance the piston travels within the cylinder. On a traditional internal combustion engine, the piston makes four strokes during the combustion cycle, only one of which is a power stroke.

Springs, dampers, shock absorbers, hydraulics, wishbones, roll bars, struts, and links used to suspend the frame, body and engine above the wheels.

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The instrument gauge that shows engine speed, or revolutions per minute. On a vehicle with manual transmission, the driver can use the tachometer to tell when to upshift or downshift.

Timing Belt
On overhead cam equipped engines, an external belt used to synchronize the operation of intake/exhaust valves with the compression/ignition process occurring in the cylinder head and engine block below.

A measure of twisting force, given in foot-pounds (abbreviated as lb.-ft.) or Newton-meters (N-m). In the case of an automobile, it is the twisting or rotational force the engine exerts on the crankshaft. Vehicle specifications often include the maximum torque an engine produces at a specific number of revolutions. An engine that produces 200 nm. @ 3,000 rpm, accelerates better at low speeds than an engine that provides 200 lb.-ft.@5,000 rpm.

Torsion Bar
A simple, rugged type of suspension spring that twists as it is compressed or stretched.

Vehicle width, measured from the center of one tyre's contact patch to the center of the opposite tyre's contact patch.

Traction Control
A system for limiting wheel slip under acceleration, thus maintaining each wheel's contact with the road surface. Traction-control systems generally use the anti-lock braking system to stop wheel spin and reduce power from one or more engine cylinders when an electronic sensor detects wheel spin.

The transmission is used to take the high-speed, low-torque power of the engine and convert it to a lower-speed, higher-torque output, which ultimately turns the drive wheels. Transmissions come in a wide variety of choices, but they basically divide into three categories: Manual, Automatic, and Tip-tronic. Lower gears allow fast acceleration; higher gears provide better gas mileage.

Trim Level
The level of options or features added to a model. An optional extra as selected by the customer, like an airbag, doesn't instigate a new trim level. Only the car maker selects the attributes to a car to make it a special variant of the basic version, which is the 'factory standard' version, and is the cheapest within the range.

Turbo Lag
The time it takes the turbocharger to kick in after the driver accelerates; the lag results because a turbocharger compressor is spun by exhaust gases in the exhaust manifold.

Device that compresses and forces extra air into the intake manifold to produce extra power. Both turbochargers and superchargers are used to produce more power without increasing engine displacement, but neither are particularly fuel efficient and both can require costly maintenance as vehicles age. By forcing fuel through the engine, this system allows the car to gather more speed. Usually they're made by specialist component makers like Roots, X-Trac, Bosch, etc.

Turning circle
The minimum distance a car needs to turn around in one step.

Tyre size
Tires are rated by load capacity, size and speed capacity. For example, a P225/50VR16 printed on the side of the tire means:
• P = P-Metric (Passenger Type Tire)
• 255 = Section Width (255mm)
• 50 = Aspect Ratio (tire height/section width)
• V = Speed Rating
• R = Type of Ply (Radial)
• 16 = Wheel Diameter (16 inches)
Tire and wheel dimensions are the first point of information in any discussion of size and capacities. Among the other terms used to describe tires are: tread, shoulder, carcass, sidewall, bead seal, bead seat, tire diameter, aspect ratio, speed rating and section width.

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Occurs when the front wheels have lost adhesion or the driver is turning the steering wheel too sharply for the vehicle's speed. In understeer, the front wheels do not follow the steering wheel angle, and the car refuses to turn and pushes ahead. In motor sports, this is called push. The driver can regain traction by reducing speed.

Unidirectional tyre
Tire whose tread pattern is designed to get optimum traction only when the tyre is mounted to roll in one direction.

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V6, V8 and so..
A vehicle with six, eight and so cylinders respectively. The cylinders are divided into two banks, each of which is angled away from the other at the top, forming a 'V'. Typically, this angle is 60 degrees on V-6 engines.

Valve Train
The valves and camshaft(s) within an engine, and any parts attached to the valves, such as rockers and pushrods, to move them up and down.

Many overhead-cam engines, particularly multi-valve models, are described by the total number of intake and exhaust valves in the cylinder head. A 24-valve V-6 engine would have four valves per cylinder: two intake and two exhaust valves. A 16-valve V-8 engine has only the standard single exhaust and single intake valve for each of its eight cylinders.

A box-shaped truck like car with a passenger area and a cargo area to the back bumper, generally used for commercial purposes.

Vented Disc Brakes
A brake disc that has cooling passages between the friction surfaces.

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Weight distribution
Measured in Kg, representing the balance, control an stability, with the centre of gravity acting as the fulcrum.

Wheel Size
Determined by the diameter and width of the wheel on which the tyre is mounted. A 15-inch wheel has a diameter of 15 inches. A 15 X 7 wheel has a 15-inch diameter and a 7-inch width.

The distance between the center of the front wheels to the center of rear wheels.

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Zero-offset steering
A steering system whose geometry has a scrub radius of zero. This configuration minimizes the steering effects produced during acceleration (with front drive) or braking on varying traction surfaces.


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