Automotive Technical Terms |
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Throughout this site we use
many technical terms, and given the breadth of readership
our site enjoys, sometimes we are remiss and incorrectly
assume everyone knows what we are referring to. For those
that do not, here are some explanations of the technical
terms use. |
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Hardtop:
A style of car body design
that has no B pillar between the doors and roof.
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Horsepower:
A British unit of power, used to define
the rate at which work is done. Has been replaced by
the kilowatt, and an approximate conversion is 100hp
= 75kW.
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Hydraulic Damper:
A shock absorber whose
damper action results from hydraulic flow through precisely
machined orifices.
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Independent Suspension:
A type of vehicle
suspension where the movement of one wheel does not
necessarily result in the movement of the other wheel,
because the wheels do not share a common axle. It is
often abbreviated to IFS for “Independent
Front Suspension”, and IRS for “Independent
Rear Suspension”.
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Inertia Reel Seatbelt:
A seat belt location
method that allows the belt to pull in and out by a
spring-loaded reel set-up as the occupant wishes, but
on sudden forward movement (ie: in a collision), the
reel locks, thus securing the occupant.
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Kingpin:
Inclined steel pivot in steel
housing that allows front wheels to turn side to side
as well as move up and down. Generally replaced by
a pair of ball joints on most modern cars.
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Laminated windscreen:
A windscreen that
is fabricated from two or more layers of glass joined
by a clear plastic layer, which is more resistant to
impact by flying stones than a conventional windscreen.
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Landau:
Also landaulette. Enclosed car
with folding rear roof. Originally chauffeur-driven
with a fixed or movable partition between front and
rear seats.
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Live axle:
Conventional rear axle set-up
that contains rotating drive shafts. The actual term
'live' refers to the fact that the axle transmits power
as opposed to a dead axle whose sole function is suspension.
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Mag wheel:
This term originally referred
to a wheel cast in magnesium or a magnesium alloy,
but now is a more loosely defined term that refers
to any cast wheel.
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Manifold:
The grouping of pipes that
distribute the inlet charge from the carburetor to
the various cylinders and likewise the exhaust gases
from the various cylinders to the exhaust system.
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MPG:
Imperial system of measuring fuel
consumption. Now replaced by liters per 100 kilometres.
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Octane:
Refers to the content of various
hydrocarbon groups in petrol. An approximate measure
of the inherent combustion energy found in a given
petrol type.
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Odometer:
A device for recording the
total distance covered by the vehicle. Driven off the
speedometer and usually located in the speedometer
face.
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Overdrive:
Refers to a gearbox ratio
where the output shaft turns faster than the input
shaft. Most gearbox ratios decrease shaft speed while
an overdrive ratio increases shaft speed. It provides
more relaxed cruising ability and reduced fuel consumption
by lowering engine speed relative to road speed.
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Overhead Camshaft:
Abbreviated OHC.
A specific type of cylinder head design where the camshaft
is located above the valve gear.
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Overhead Valve:
Abbreviated OHV. Refers
to design where the valves a above the combustion chambers
but are actuated through pushrods by a camshaft located
below the cylinder head.
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Oversteer:
Handling characteristic of
a vehicle that refers to the tendency for the rear
wheels to run wide in a corner, thus steering the front
of the vehicle increasingly into a corner.
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