Which to me is useless. We already use the brakes individually for traction control, which does the same thing. All that slowing the half-shafts on the rear does is make your brakes last longer and maybe not heat up as much. It doesn't save any overall weight. We're up to near 3500 pounds for an R now and you probably still need to change the oil in it. How are the clutch packs applied, another one(or two) hydraulic pumps?
https://www.autocar.co.uk/car-news/features/clash-pan-torque-vectoring-hot-hatches-face
The system in the Golf R works like this. Torque flows through the gearbox and into an open differential on the front axle. From that sprouts an output shaft that runs to the rear axle. Previously on the Golf R, that shaft fed into a clutch pack that, once engaged, allowed 50% of total engine torque to drive the rear axle through another open differential, with the torque split equally between the wheels. The Mk7’s ‘Gen 5’ Haldex clutch pack worked rapidly, too, being electronically governed and preloaded with hydraulic pressure.
However, in the Mk8, there’s no clutch pack before the back axle. The propshaft that unifies each end of the car instead takes drive into the rear axle via a pair of simple bevel gears; and it’s the electromechanical clutch packs that sit either side of those bevel gears that control and manipulate the amount of torque that ends up at each wheel. If the left-hand pack is completely open and the right-pack fully engaged, as is sometimes the case in Drift mode, all available torque (again, only up to half of what the engine is making) will surge to the right-hand wheel – and vice versa.
But any ratio is possible, because that’s what clutch-based vectoring permits. It’s up to the development engineers to devise how the torque splitter should behave, depending not only on driving mode but, within that broad parameter, also the throttle position, steering angle, cornering g-forces, what the electronic stability programme (ESP) is saying… and on it goes.
“Drift mode is an over-the-top application,” says Jonas Thielebein, the engineer who oversaw the Mk8 Golf R project, “because normally you don’t want your car to slip.” He says the sweet spot is generally to have a less extreme calibration, where the car rotates just a touch, to the extent that the driver can feel it but onlookers can’t actually see it. “That’s the way to drive fast, and that’s what we try to do,” he says, before explaining that if you do ever explore the car’s Drift mode, one of the rear clutch packs really does remain “nearly permanently open”.
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