N00b here!

As this is my first post, I might as well say hi to everyone

I'm sorry to repost on a subject that I see has been covered, re-covered and covered again for good measure (!) but I couldn't find a well explained answer to help me, hence my question:

What is "Locking Factor" on the Clutch Pack LSD?

I have been having lots of fun getting my head around setups this week and have found a setup I really like using some settings from a setup I downloaded with some major adjustments of my own (thanks to Bob Smith/Ben Ponsford for the VHPA which has been a major help). But I need some help getting my head around this. My downloaded setup has a locked diff for some reason which will obviously cause some unwated resistance during cornering so I need to setup the Clutch Pack LSD from scratch.

The way I understand it, Preload basically adjusts the spring strength, increasing/decreasing the friction between the side gears and the clutches. The torque in Nm's then makes sense as the amount of torque required for a wheel to break free of the clutch and become unlocked. Am I right?

But locking factor has me utterly confused. Maybe LFS needs to word this setting differently or something. I am guessing that it relates to the additional pressure put upon the LSD clutches by the torque being transmitted via the drive shaft??

So, say I had a power locking factor of 70%, this would mean that the Preload torque would be increased by 70% of the input torque under accelleration??

Please help me understand if this is right

The maximum difference between the output torques on either side of the diff, at any instantaneous moment, can obviously be expressed as a torque. For a clutch pack LSD, this torque typically expressed as a percentage of the input torque to the differential, as the more input torque a clutch pack diff receives (due to the fixed ramp angles inside the diff), the harder the diff tries to lock the output shafts together.

An example:
Engine outputs 400Nm torque
Combined gearbox and final ratio is 8:1
Diff input torque is 3200Nm
Locking factor is 50%
So maximum difference between the left and right tyres is 50% of 3200Nm, or 1600Nm, meaning one tyre gets at least 800Nm, while the other gets no more than 2400Nm. This diff could also be expressed as having a torque bias ratio of 3.0 (2400/800).

Pre-load merely enforces a minimum to this torque difference, so for example if you were to come off the throttle and the engine produces zero torque (this engine magically has no engine braking), so your locking factor means the maxmium torque difference is now 0Nm, or in other words an open diff. Which you probably don't want, as this can create a very instable feeling when the engine produces little torque (especially if the setup was relying on the diff locking to create understeer).

Continuing the example:
Pre-load torque: 100Nm
Thus the crossover point is when the diff input torque drops below (100/50% or) 200Nm (or for this example gear, when the engine torque drops below 25Nm). Below this torque, the pre-lead is having an effect, above this, it is not. This torque is around 6% of the maximum torque, so you can see that pre-load only effects handling when at very low throttle, e.g. on corner entry.