| Narrow
track vehicle |
A
term used to describe a narrow, off-road vehicle such as a Jeep or
compact pickup trucks which can more easily negotiate narrow logging
roads and mountain trails. |
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| National
Highway Traffic Safety Administration (NHTSA) |
An
agency within the U.S. Department of Transportation that establishes
and enforces automotive safety regulations. |
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| Naturally
aspirated |
An
engine that the pistons draw air into the cylinders without the
use of a supercharger or turbocharger. When pistons travel downward
in their cylinders, a vacuum is created in the intake manifold.
When outside air is "sucked" into the intake manifold,
it travels past the carburetor where a fine spray of fuel is added.
By
contrast, a turbocharger or supercharger (blower) forces air into
the engine increasing the density of the air/fuel charge going into
the cylinders, and ultimately producing more power. Also see Supercharger
and Turbocharger.
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| Navigation
system |
A
computerized system found in some vehicles that typically uses a monitor
to display maps showing streets and present location. Helps a driver
orient themself and more easily arrive at their destination. Often
hooked up to a GPS system. |
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| Navigator |
See
Navigation System (above).
Also,
the name of a large, luxury sport utility vehicle manufactured by
Lincoln.
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| Needle |
1.
Another term for a carburetor metering rod. See Metering Rod. 2.
A
name often applied to Needle-and-seat valve (see below) 3. A long
roller used in a needle bearing See Needle bearing (below).
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| Needle-and-seat |
A
valve assembly that regulates fuel flow to an engine's carburetor.
A carburetor holds a certain amount of fuel (usually about a cup).
The fuel level is maintained by the needle-and-seat valve and the
float. When fuel level in the carburetor decreases, the float lowers
and moves the cone-shaped needle off it's seat which allows fuel to
enter. As fuel enters, the float rises until the cone-shaped needle
fits tightly into place again reducing, or cutting off fuel flow.
This continued action maintains a consistent fuel level inside the
carburetor. |
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|
| Needle
bearing |
A
type of roller bearing that uses small, long, barrel-shaped steel
"rollers" to reduce rotating friction. Needle bearings are
low-profile and are typically used in applications where space is
critical. Needle bearings are often found in drive shaft universal
joints, and inside transmissions. |
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| Negative
camber |
A
wheel alignment setting. Camber is the inward or outward tilt of a
wheel from vertical. Camber is measured in degrees and can be Positive,
or Negative. Negative camber results when the top of the wheel is
tilted inward. As an example, 3 degrees negative camber means, the
top of a wheel would be tilted inward towards the center of the vehicle
3 degrees (from vertical). A high degree of negative camber is desirable
for certain racing events such a the slalom as it can aid cornering. |
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| Negative
offset |
Negative offset is when the steering axis (line from upper ball joint
or strut through lower ball joint to ground) is outside the center
of the tire's contact area on the ground. In simple terms, negative
offset moves the tire inwards, positive offset moves it outward. A
term one often encountered when purchasing new wheels. |
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| Neon
lights |
Battery
operated neon light tubes which street rodders sometimes place underneath
their vehicle or around the license plate. Creates a unique glow beneath
the vehicle. |
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| Nerf
bars |
Sturdy
tubular bars mounted to the frame and below the doors of a pickup
truck. A popular off-road accessory installed on pickups and SUV's.
Typical nerf bars run from behind the front wheel to just in front
of the rear wheel. The purpose is to minimize damage to the rocker
panels during off-road driving. |
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| Net
horsepower |
The
maximum power output of a motor (horsepower and/or torque) measured
on a dynamometer with exhaust system and normal intake and all engine
accessories installed. |
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| Net
torque |
See
Net Horsepower (above). |
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| Neutral |
A
transmission shift position where no gears are selected and no power
from the engine is transferred to the drive wheels. |
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| Neutral
handling |
A
handling term used to describe a condition where neither understeer
or oversteer are particularly predominant. |
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| Neutral
steer |
A
handling condition where neither oversteer or understeer are predominant.
In a neutral steer condition, the slip angles of the front and rear
wheels are nearly equal. In such a condition, if a driver were to
drive around a corner past the limit of adhesion, both front and wheels
would "break free" at the same time. Since such loss of
control is relatively unpredictable -- a slight amount of negative
understeer is desirable. See Understeer and Oversteer. |
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| NHTSA |
See
National Highway Traffic Safety Administration (above). |
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| Nibble |
A
condition where tires try to follow grooves in the road. Often felt
as a pulling or tugging feeling on the steering wheel. A dangerous
condition because it can lead to accidents. Tires are the main cause
of this. Older, bias belted tires with their stiffer sidewall construction
were more prone to nibble. Modern radial tires have a more flexible
sidewall and wider tread spacing which reduces nibble. |
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| Nitrous
oxide (N2O) |
Commonly
referred to as laughing gas. Used in drag race cars and street
rods in short bursts to improve combustion and produce more power.
During combustion, N2O breaks down into nitrogen and oxygen. Because
there is more oxygen mixed in with the air/fuel mixture, more gasoline
can be burned. The extra power can be significant but must be used
in short bursts to avoid over-stressing an engine. |
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| Noise
suppresser |
A
device, usually a small isolation transformer, which can be placed
in series in the power line of a car stereo or amplifier to reduce
buzzing or other engine and alternator noises. |
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| Nominal
sectional height |
The
height of a tire from the rim seat (where the bead seals to the rim)
to the surface of the tire's tread measured at the top or sides of
the tire. |
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| Nominal
section width |
The
maximum width of a tire in millimeters measured from sidewall to sidewall
of an unloaded tire (measured at the top or sides of the tire). |
|
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| Nominal
wheel diameter |
The
diameter of a tire rim from beat seat to bead seat. Expressed in inches,
i.e. 15" rim. |
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| Normally
aspirated |
See
Naturally aspirated (above). |
|
|
| North-south |
A
term used to express engine orientation that is parallel to the length
of the vehicle such as used in a typical front engine, rear-wheel-drive
vehicle. For example, pickup trucks engines sit in a north-south orientation.
A typical front-wheel-drive car engine would be mounted in an east-west
fashion. |
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| Notchback |
A
passenger car body style with a distinctive vertical slope to the
rear window and rear roof line. Typical of the rear roof line of most
full-sized four-door family sedans. A notchback can be hatchback but
not a station wagon or fastback. Also see Fastback. |
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|
| Numeric
rating system |
A
tire rating system used in the days of vintage automobiles. An example
is 7.00-15, where 7 is the section width and 15, the rim diameter.
No longer in use. |
