I am a newbie at this...what is a LSD? my friend told me that it transfers all the power to the wheels. Saying, that a car, like a Supra, can create like 1,000HP but it needs something to put all that power to the wheels. Please explain.

 

I am not an expert but it does this. In most differentials,open type, only one wheel spins and moves the car. In an lsd(limited slip differential), both wheels will spin and move the car. There are many types: two way, gear type, clutch type, and a few more. The biggest purpose of a differential is on a turn. On a turn one wheel will need more power than the other wheel and the LSD will transfer the power to the wheels that needs it. I think that answers most of your question. Some good LSD's are quiafe, Kazz, and Cusco.

 

Limited
Slip
Differential

Meaning that, for example, on a front wheel drive you will have both front wheels putting power to the gound opposite to most stock FWD car having an open differential that has only one wheel putting all the engines power to the ground. It will start spinning a lot easier, and you will then waste the power from your engine, whereas an LSD will have two ends of the differential applying power to the ground instead of one wheel on an open differential......
Get it?

 

DAMMIT. I had a nice write up written and the internet timed out!!

.

Read the following links.
http://www.howstuffworks.com/differential6.htm (Clutch)
http://www.howstuffworks.com/differential7.htm (Viscous)
http://www.howstuffworks.com/differential8.htm (Torsen and Lock almost like a gear)

The below is not exactly accurate.

[Modified by Spade, 8:00 AM 1/21/2003]