Originally Posted By: Olas
Thing is, as ana electric system handed works off request, where Torsten has infinite variability and works instantly, on a demand basis.
The more elegant solution just so happens to have won the WRC
The Haldex system in question, fourth gen (aka XWD), is not a "part-time" system. It is a continuously variable electro-hydraulic system that also features an eLSD. It uses fluid pressure, not a simple on/off electromagnet clutch or gerotor pump, to control torque both at the center diff (aka coupling) and across the rear diff.
It is just as variable as a Torsen system, sometimes even more so if the COF is low enough, and is also predictive, being able to proactively vector torque, something Torsen is unable to do.
Don't get me wrong, there is nothing wrong with an AWD system using a Torsen diff center and rear, like many Audis use. However, it is no more favorable to a high-performance electro-hydraulic system like Haldex fourth gen, Honda SH-AWD, or any other system that incorporates a torque vectoring component like ZF VectorDrive.