Technical Analysis: WRC Cars 2017

[Kris82]

I have a question about center differentials on the new 2017 spec cars. How do they work exactly. The way I understand it the active center differential can be either open or locked and the state is hydraulically controlled with help of electronics. While locked, front and rear axles act as if there was no differential (like in previous models) and when it's open it acts like a front open differential on a regular road car, when one side loses grip then it spins out robbing the torque from other side. The active part lets it go between both states depending on the data from a number of sensors. The power split between the axles is 50/50 on WRC cars as far as I know (correct me if I'm wrong). Now what confuses me are the problems Ogier had faced in Rally Corsica. His hydraulics had failed and he ended up with a rear wheel drive vehicle. Shouldn't he had ended up with an open differential instead, since the hydraulics would be responsible for locking the center differential?