what is the difference between open and lock diff
 

what is the difference

no idea what open is but locked is when your diff. dosent move

open Ex. ball diff/ gear diff= you hold one wheel and the other spins faster or spins.

locked Ex. gear diff w/paper or superglued= both wheels spin together.

i know open is beter for turning, but what about off the line, wouldnt an open diff give you betr traction on the hole shot by reducing wheel spin

whats better for drift

Open vs. Locked
 

Okay,
An 'open' differential is what you find your average car. It allows one wheel to spin at a different speed than the other, such as going around a corner. This saves wear and tear on the drivetrain and tires. However, if you get stuck, all the power gets transferred to the slipping wheel...no good.
A 'limited slip' differential usually uses internal clutches to help transfer some power to the slipping wheel. There are many different types of limited slip differentials. The ball diff. for the XMODS is a limited slip type diff. These would be a good choice for road racing or drag racing.
A 'locked' differntial is, as the name implies, when the axles are locked together. The only time they are not locked is under a coasting condition. Anytime power is applied, the axles are locked. This type of locker can cause erratic handling and is mostly used in off-road vehilcles (mudding, rock crawling).
Finally, a 'spool' permantly locks the axles together no matter if you are on or off power. This is really only used in things like Top Fuel drag racing, where handling in the corners is not needed. I would not recommend this for the XMODS except for drag racing.

Hope this helps!

If you are making a lot of power the ball type diff will slip and your power will not reach the ground so only use it on an AWD set up.
For my experiments Locked will only work well for drifting and drag. Put some thick paper in the diff to lock it.

I didn't like the open diff because one wheel would spin coming out of a corner and it would not accel fast. To make a limited slip diff(LSD) you can use paper from a hole puch between the 2 flat gears. This caused erratic handling because it was not smooth.

I went to the local bicycle shop and he gave some thick white grease in a plastic baggy which worked flawlessly as a limited slip differential. It will give you optimal handling and power. Pack it in their tight though.