Car Magazine website has the following on the new B8:
"Quattro four-wheel drive is, of course, standard, with a crown-gear centre differential sporting a standard 40:60 front-to-rear power split, but with the ability to send 70% of torque to the front or 85% to the rear. And there’s torque vectoring too, with the electronics braking the inside wheels to reduce slip, while the optional Sport differential can distribute power between the rear wheels."
From my own understanding (and a quick refresher on wikipedia
), the B7 RS4 has the following:(a) a Torsen T3 'torque sensing' differential which works at 40:60 front:rear torque split in normal conditions;
(b) torque bias ratio of 4:1, meaning that up to 80% of the applied torque can be directed to the rear in certain conditions;
(c) an electronic differential lock between wheels on the same axle (or Anti Slip Regulation).
Comparing the old with the new, this is how I interpret the similarities/changes:
1. they both have a Torsen diff (which is a crown gear differential);
2. the front:rear 'normal' power split is unchanged;
3. the 'ability to send 70% of torque to the front or 85% to the rear' is a new computer controlled feature, and is a replacement for the Torsen's Torque Bias Ratio;
4. torque vectoring is a new addition, kind of a version 2.0 of the Anti Slip Regulation;
5. the new sport differential is for the rear axle and replaces the open diff on that axle that base B8 RS4s and all B7 RS4s have.
Have I done my homework right? Bring on the experts!!
Cheers in advance.
Stu[edited for clarity and to add comparison no.5 to the list]