and amp;gt; so are you trying to say when we get the ACD to lock quicker and with more pressure
and amp;gt; as the ACD K1 unit does it will make the AYC WORK LESS and give the front end more grip?
Hmm, it looks like we will have to go deep here!!
In general, cars with LSDs in the center and in the back have a built in feature - to understeer! Or more precise would be to say that LSDs don't allow the car to loose the rear end that easy. Rear end starts coming around when you start loosing the traction back there. Loosing of the traction means spinning of the rear wheel(s) (assuming we are talking about throttled applications) will cause difference in the speed between the front and the rear. That will make center LSD to starts locking more. Since it was more opened moment ago, more power was in the rear. By having the center locked you get more power to the front than earlier. That extra power basically makes the front end to push. To make it worse, rear end gains the traction and starts going where the wheels are pointing to (means less rotation of the rear), which creates even more push (or wash out effect).
Now there are different ways to fix this bad habit. One of them is AYC. That one sends more power to the outside wheel and makes car more loose there. At the same time inside wheel is not following the outside one (which mean that it is spinning at the lower speed), so overall speed of the rear end of the car (from the center diff point of view) doesn't increase as much as it would be in the car with conventional diff. So, center diff doesn't sense much of the difference and doesn't have to send extra power to the front. That helps two things. One is that front end stays where it was and doesn't go wider, and the second one is that rear end keeps rotating, so whole car is cornering way better. That is kind of the way it was done on the EVO 6.
In the more extreme situation, this combination is not enough (at least according to the Mitsubishi), since front end would still get some extra power from time to time (I guess, for the tighter turns this would be a bigger problem). So, solution for this is an ACD! With the control of the central distribution, car's ECU has even more freedom to control how the car is going to behave, and that is the beauty of it!
But there is something tricky about the way this works and this is what creates most of the confusion. ACD can either be fully opened (power goes wherever is easier - note no direct control in here like the AYC has) or it can be fully locked. In that case you get 50-50% power/torque distribution.
Now we can go back to the original question about the AYC having to work less or more depending on the ACD mode. If your ACD locks quicker and with more power, than AYC will have to do more work in order to keep car to rotate. If it doesn't, car will have more push, and that wouldn't be the best thing. But, by having quicker and stronger ACD in the car helps to quicker gain control of the car and stabilizes it better than the stock one. That helps in the situation when you have to counter steer or braking, for example. Remember that both ACD and AYC are controlled by the same unit and they always work together to achieve the same goal. It would be the same as having faster reacting joystick in your hand. You can move faster your objects on the screen, but you don't use that extra speed most of the time. It is just nice to know it is there!!
Of course as any control system, too much of the gain could make the while system to oscillate more or even to make it unstable. I have seen a mouse cursor moving too fast!
Hope I helped a bit in here....
Have a good one
Fedja
