Help me understand the LSD

OK...I know what a differential does. It allows the drive wheels to spin at different speeds to allow a car to turn since the inside wheel will be travelling at a lower speed. Simple enough.

So what exactly does an LSD do? Does it simply make the wheels resist spinning at different speeds, but still allow it? How does it help in racing?

An LSD or limited slip differential works just like an open diff, sending power to both wheels while allowing them to spin at differnt speeds. the differnce is that where as a standard open diff will imidiately route power through the path of least resistance when the wheels rotate at differnt speeds, (ie more power to the wheel thats slipping) an LSD will resist that action, sending power equaly to both wheels as long as the difference in rotational speeds is within a certain threshold. but eventualy an LSD will let go just like an open diff. the full customize LSD in GT3 allows you to set the level of lock that occurs under acceleration, coasting, and breaking, I like to set the accel side to full lock while leaving the initial and decel side open. the abs system in GT3 does a good enough job keeping the vehicle stable under breaking, and you want the wheels to be able to rotate freely in the corner so as not to disrupt the rotation of the vehicle and slow down cornering speeds just like ASM. cornering is a constant deviation from a strait path. in essence controlled instability. so any device that creates stability hinders cornering. But you need the locking on the accel side so that both wheels can power you out of the corners.

Let me see if I understand this...

You're turning sharply, none of the tires are sliding, and then you hit the gas. Under a standard differential (The same as open, right?), you run the possibility of the inside tire beginning to spin (because of weight being transferred off that wheel) while the outside tire still grips, resulting in very little actual acceleration while your foot is on the gas. By installing an LSD, it resists allowing that inside wheel to being slipping.

Would that be correct?

BINGO!

that means yes.

Hmm...I just thought of something...

Would the LSD be an extremely important part for drifting? By not allowing the tires to spin at different speeds, you would basically force them to slide around a corner, making it much easier to get the car sideways.

Maybe that's why I have such a hard time drifting...I haven't been using an LSD.

That's correct. A limited-slip diff helps in a powerful RWD car by allowing you to use power to break both rear tires loose. Of course, someone driving for speed would use throttle control and the LSD to maximimize the amount of power being put down, but purposely overwhelming both rear tires is called powersliding, and is a form of drifting.