Exhaust Pipe
The long steel tube that routes exhaust gases from the exhaust manifold through the catalytic converter and muffler and into the atmosphere.

Expansion Plug (See: Core Plug)

Filter
A device to remove suspended impurities or particles of foreign matter from the air intake, fuel or lubricating system.

Final Drive Ratio
The ratio between the transmission output shaft r.p.m. and the drive-wheel axle shaft r.p.m. It is determined by the ring and pinion gear inside the differential. For example, if the ratio is 4.00:1, the driveshaft rotates four times for each rotation of the rear axle differential gear, the axle shafts and the wheels. A car's acceleration and fuel economy can be altered by the final drive ratio. A low numerical axle ratio (example: 3.07) is known as a fast ratio, because road speed is relatively fast for any given engine speed. The characteristics of this ratio are: lower engine speed, reduction in performance ability and lower engine revolution per mile so fuel economy is improved. A high numerical axle ratio (example: 3.73) is known as a slow ratio, because the road speed is relatively slower as compared to the engine speed. The effects are: raised engine speed, increased performance ability, increased engine revolutions per mile and increased fuel consumption.

Firing Order
The sequence in which the spark is delivered to an engine's cylinders.

Fist-Type Disc Brakes
This style of disc brake features solid brake disc rotors and uses more clearance between the disc and the pad, virtually eliminating friction creating drag. The result is higher fuel efficiency.

Foot Pound
A unit of work equal to the amount of energy required to raise a weight of one pound a distance of one foot. Torque is measured in foot pounds

Four Valve Head
A cylinder head that employs two intake and two exhaust valves per cylinder to provide increased operating efficiency and higher r.p.m.

Four-Wheel Drive
A type of drive system in which both the front and rear wheels transmit power to the ground. Four wheel drive can be either full-time, in which power is delivered to both axles at all times, or part-time, where the driver can select either two-wheel drive only or four-wheel drive for marginal traction conditions. Our 4x4 Hardbody and Pathfinder models feature part-time four-wheel drive. Some 4x4 systems use front wheel drive in the 4x2 mode (Stanza Wagon), and the 4x4 mode engages the rear wheel drive. (Also see: All- Wheel Drive)

Four-Wheel Independent Suspension
A type of suspension in which all wheels are mounted to separate suspension members with no rigid axle connecting them. Therefore a disturbance affecting one wheel has no effect on the opposite wheel. Four-wheel independent suspension reduces the un-sprung weight, improves ride and handling over rough surfaces and permits room for a larger trunk. The Sentra, Pulsar NX, Stanza, Axxess, 240SX, Maxima and 300ZX all feature four wheel independent suspension.

Four-Wheel Steering (4WS) HICAS, HICAS II and Super HICAS
Four-wheel steering is a generic term that covers a number of very different types of steering systems. Basically, there are two broad categories of four-wheel steering: A. Stability type steering -- steers the rear wheels in phase with the front wheels to enhance the stability of the vehicle during abrupt maneuvers at normal road speeds. B. Maneuverability type steering -- steers the rear wheels in the opposite phase with the front wheels to reduce the turning circle during low speed, tight cornering. This "phase delay" also includes opposite phase steering at high speed.

Nissan's current version of 4WS is called HICAS, which stands for HI Capacity Actively controlled Suspension. There are 3 versions of HICAS in various stages of development, all of which are stability type systems only. A. HICAS -- Stability type system applied to the rear wheels. In production on the Nissan Skyline Coupe in Japan since 1985. B. HICAS II -- Same as HICAS except with "phase delay;" note: also includes opposite phase steering at high speed built into the system logic which delays turning the rear wheels to improve vehicle turn-in. This "phase delay" also includes opposite phase steering at high speed. C. Super HICAS--same as HICASII except front wheels also have some elements of active control.

Frame
The structural, load-carrying members of a car or truck that support the engine and body and are in turn supported by the car wheels. In the case of 4x2 Hardbodys, the frame is the familiar ladder/lattice type, which adds strength and rigidity. The 4x4 Hardbodys and Pathfinder use a four sided box section frame which is durable and rigid.

Freeze Plug (See: Core Plug)

FF
This is the abbreviation for front engine/front wheel drive, a system in which the engine is installed in front of the passenger compartment and drives the front wheels. The drive system for front engine vehicles is designed so that the transmission is connected by driving axles to the front wheels instead of the rear wheels. Advantages of this method include reduced weight, increased interior space and better traction in many situations. Our Stanza, A~xess 2WD, Maxima, Sentra, and Pulsar NX all feature front-wheel drive.

FR
This is the abbreviation for front engine/rear wheel drive, in which the engine is installed in front of the passenger compartment and drives the rear . wheels. This arrangement is featured on the 240SX, 300ZX, Hardbodys, Pathfinder 4x2 and Van. The benefit in sports cars is better dry road handling and better weight distribution.

Fuel Injection
A type of fuel system using a pump and injectors instead of a carburetor to meter fuel. There are two main types of injection: direct cylinder injection, which sprays the fuel right into the combustion chamber, is known as multi-point or port injection; single point or throttle body injection puts the fuel charge into the intake passage somewhere upstream of the intake valve. Fuel delivery can be controlled mechanically or electrically and can be either pulsed, continuous or a combination of the two. Pulsed injection precisely controls the length of time the fuel is squirted whereas continuous injection makes no attempt at timed squirts, but rather regulates the quantity of steady flow. Sentra, Pulsar NX XE, four-cylinder Hardbodys, Pathfinder and Van use single point injection. Pulsar NX SE, Maxima, and 300ZX use multi-point injection. 240SX uses full time sequential multi-point injection. These injectors fire sequentially all of the time. B. Electronic Fuel Injection (EFI)-- A modern, efficient method of fuel delivery, electronic fuel injection replaces carburetors in all Nissan engines. By precisely controlling the amount of fuel used and improving the dispersion of fuel in the air charge, EFI improves driveability and performance of the engine. C. (Manufactured by Bosch) L-Jetronic fuel injection sprays fuel into the intake manifold at a constant pressure relative to manifold pressure, but with pulses of varying duration. This allows precise balancing of the air/fuel mixture to match engine load. In the case of all Nissan models, the injection is controlled by a computerized "black box" that monitors various engine functions, then makes the appropriate adjustments in the air/fuel mixture for maximum performance and economy.

Fuel Pump
A mechanical or electrical device that draws fuel from the fuel tank and delivers it to the carburetor or injectors.

Fuel System
The system that delivers fuel to the engine. It consists of the fuel tank, fuel lines, fuel filter, fuel pump and the carburetor or fuel injection.

Full Floating Axle
A drive axle construction where the axle drive shaft does not carry any of the car weight.

Fuse
A slender wire that melts or separates if excessive current flows through it, thus protecting the circuit it was installed in from a possible overload. .

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