Limited Slip Differential (FAQ)

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Drivetrain

This article is part of our special collection:

FAQ

General LSD Questions

What is a Limited Slip Differential

Types of LSDs

1.5 way LSD

Activates under acceleration while the under-steer under deceleration is less than on a 2 way LSD. Recommended for those who have a hard time with under-steer.

2 way LSD

Recommended on rear wheel drive cars and AWD rear axle cars. Activates on both acceleration and deceleration. Recommended for those who prefer aggressive driving and big angle drifting.

Viscous Limited Slip Differential

The viscous type is generally simpler, and relies on the properties of viscous oils that is, one whose viscosity varies as the inverse proportion of an applied force. Silicon-based oils are often used.Petroleum by-product oils can also be used, Here, a chamber of fluid rotates with the normal motion of the output shafts, but a differential motion causes paddles or vanes to move through the oil. The greater the speed of the fins, the more resistance the fluid will put up to oppose this motion. In relation to the mechanical type, the limiting action is much softer and more proportional to the slip, so for the average driver is generally much easier to cope with.

Viscous LSDs are less efficient than mechanical types, that is, they "lose" some power. However, they are less prone to breakdown as long as the fluid is changed regularly.

Will adding an LSD to my car improve...

Acceleration

Cornering

Horsepower

A limited slip differential has little effect on horsepower. All differentials will rob a small amount of power, but the viscous types are said to be the worst.

350Z Specific Questions

What models are equipped with a LSD?

Only the base model does not include the viscous LSD.

What type of LSD does the 350Z have?

The factory LSD is a viscous type.

Who makes aftermarket LSDs for the 350Z?

See Limited Slip Differentials for a comprehensive listing and comparison of all the currently available aftermarket LSDs for the Nissan 350Z.

Drivetrain Definitions

Axle

An axle is a central shaft for a rotating wheel or gear. In some cases the axle may be fixed in position with a bearing or bushing sitting inside the hole in the wheel or gear to allow the wheel or gear to rotate around the axle. In other cases the wheel or gear may be fixed to the axle, with bearings or bushings provided at the mounting points where the axle is supported.

Clutch

A clutch is a subcomponent of an engine's transmission designed to allow engagement or disengagement of the engine to the gearbox or whatever apparatus is being driven.

The coupling mechanism used on a mechanical power press to couple the flywheel to the crankshaft, either directly or through a gear train.

Differential

A set of mechanical gears that eqaulises the power between the left and right drive wheels, particularly when cornering, when the outside wheel travels further than the inside wheel.

A device - usually made of gears - that divides the torque between the driving wheels and permits the wheels to turn at different speeds. This is especially important when negotiating a corner, as the inside wheels turn more slowly than the outside wheels.

A unit that takes the power of the rotating driveshaft at right angles to the rear axle and passes it to the axle. It will not only drive both rear axles at the same time, but will also allow them to turn at different speeds when negotiating turns. In this way the tires do not scuff or skid.

Driveshaft

A driveshaft or driving shaft is a mechanical device for transferring power from the engine or motor to the point where useful work is applied. The 350Z incorporates a one-piece driveshaft which is actually carbon fiber reinforced plastic.

Final Drive

Flywheel

A relatively large and heavy metal wheel that is attached to the back of the crankshaft to smooth out the firing impulses. It provides inertia to keep the crankshaft turning smoothly during the periods when no power is being applied. It also forms a base for the starter ring gear and, in manual transmission, for the clutch assembly. Also see engine flywheel and fluid flywheel.

This is a large gear mounted to the back of the crankshaft which turns the engine when the starter is cranking.

A flywheel is a heavy rotating disk used as a repository for angular momentum. Flywheels resist changes in their rotation speed, which helps steady the rotation of the shaft when an uneven torque is exerted on it by its power source such as a piston-based, (reciprocating) engine, or when the load placed on it is intermittent (such as a piston-based pump).

Gearbox

A casing for gear sets that transmit power from one rotating shaft to another. A gear box has a number of functions: it is precisely bored to control gear and shaft alignment, it contains the gear oil, and it protects the gears and lubricant from water, dust, and other environmental contaminants. Gear boxes are used in a wide range of industrial, automotive, and home machinery.

The shell (metal casing) in which a train of gears is sealed.

Gear Ratio

The number of revolutions a driving (pinion) gear requires to turn a driven (ring) gear through one complete revolution. For a pair of gears, the ratio is found by dividing the number of teeth on the driven gear by the number of teeth on the driving pinion gear.

A gearbox contains several toothed wheels that are connected and disconnected to each other in order to switch into the intended gear. The gear ratio is the ratio between the number of teeth of the two wheels that are connected at a given time. If one wheel has 25 teeth and the attached one has 50, there is a 2:1 ratio.

Limited Slip Differential

A Limited Slip Differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In a car or automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.

Pumpkin

The rear pumpkin, or carrier, houses the final drive gears and differential.

Short Shifter

Toe

Toe relates to the difference in the distance between the front of the tires and the rear of the tires on the same axle, or to the vehicle centerline. Toe-in, or positive toe, is defined as the front of the tires being closer together than the rear of the tires. Toe-out, or negative toe, is when the rear of the tires are closer together than the front of the tires. Zero toe is when the tires are parallel to each other.

Effects of Toe: Excessive toe increases tire scuffing and results in tire wear and drag on the vehicle. Excessive toe-in, or positive toe, increases scuffing on the outside of the tire. Excessive toe-out, or negative toe, increases scuffing on the inside of the tire, and in some cases can cause a darting or wandering problem. Bias or bias-belted tires will commonly show a featheredge or saw-tooth toe wear pattern across the entire tire tread area. Any tire wear pattern caused by a toe condition can be further affected by an excess camber condition and may result in irregular wear patterns.

Drivetrain