1. Limited Slip Differential
By Yan Chen

2. Why do we need a differential?
To improve performance (better cornering)
To improve safety
To reduce tire wear
To reduce stress on axle and gearbox

3. What is a differential? A differential is a device that:
Aim the engine power at the wheel
Can act as a final gear reduction in a vehicle
Transmit power to the wheel while allowing them to rotate at different speed

4. What is a limited slip differential?
A modified open differential
Allow more torque to be transfer to non-slipping wheel when wheel(s) loose traction
There are two main types:
Mechanical
Viscous

5. Mechanical
All mechanical differential incorporate parts of an open differential
Uses a clutch or some locking mechanism to resist slippage
Advantage
most effective
Disadvantage
Less reliable
More expensive

6. Viscous
A chamber of fluids housing two set of plates (usually silicon based oil)
When slippage occurs, one set of plate spins faster, causing the fluid to spin faster which forces the other set of plates to spin faster.
Advantage
More reliable
Cheaper
Disadvantage
Reacts to slippage (not resist slippage)

7. Reference http://auto.howstuffworks.com/differential.htm