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Electric torque vectoring a reason to be cheerful

Concerned about the tidal wave of electric performance cars? Well, it's definitely not all bad news...

By Dan Prosser / Saturday, December 7, 2019

I spent a full day this week behind the wheel of the Porsche Taycan 4S, although I can't tell you a great deal about the car. That's partly because I've signed an official-looking piece of paper agreeing not to until early next week, but also because I only drove it on snow covered roads in Finnish Lapland and on sheet ice at Porsche's experience centre up there in the Arctic Circle. You learn so little about a car on snow and ice that I couldn't shed a great deal of light on the entry-level Taycan even if I was allowed to.

But I can tell you about its trick torque vectoring capability. Like the Turbo and Turbo S, the 4S has pair of electric motors - one on each axle. On its prow it uses the same motor as the more expensive models, while at the rear you'll find a smaller one. That explains why, when the Turbo develops 680hp and the Turbo S 761hp, the 4S makes do with a frankly laughable 571hp (or 530hp if you don't specify Performance Battery Plus).

The active limited slip differential (PTV+) that is standard kit on range-topping Taycans is available optionally on the £83,367 base model. You'll need that in the back of your 4S if you want it to vector torque to the fullness of Porsche's capabilities, but even without it the Taycan will pull off stunts beyond the limit of adhesion that no conventional combustion engine machine with four-wheel drive could ever manage.

'Electric torque vectoring is faster to react and more precise than combustion engine torque vectoring,' says Taycan engineer, Christian Wolfsried. 'It's maybe ten times faster. But the big advantage is there's no physical connection between the front and rear axles. That means we can make the Taycan's front axle slip [or over-rotate] without the rear axle slipping. You can't do that on a conventional car with hang-on four-wheel drive; it's not physically possible.'

The significance of that? It means the Taycan can be chucked to a 90-degree angle in a corner and if the driver stands on the accelerator pedal hard enough, it'll be pulled back into line. The torque vectoring system will cut drive to the rear end and spin the front motor up as forcefully as possible, dragging the car straight. Try the same in a Panamera, for instance, and the rear axle will have to slip in order to make the front over-rotate, meaning the car probably won't exit the corner pointing in the right direction.

So with electric torque vectoring, you can save much bigger slides than with the conventional kind. Wolfsried ably demonstrated this point by taking me for a pre-dinner dash through the pitch black woods in a Taycan Turbo S with studded tyres. On the little wriggly road that ducked and weaved between the pines, he flung the car to hilarious angles of drift and brought it back into line using that unusual torque vectoring capability.

Of course, a Panamera with its interconnected axles and intelligent four-wheel drive system can send the fullness of its power to either end, whereas a car with two disconnected power units, such as the Taycan, can only ever distribute so much to a given axle. But there's no torque curve to worry about on the Taycan and you'd never need more than one motor's worth of shove to make the car dance balletically.

When an electric car has one motor for each wheel, it can be made to do really extraordinary things. I once watched an Audi RS3 kitted out with four Formula E motors perform donuts on the spot without travelling an inch in any direction. It was effectively spinning like a tank, its tracks pulling in opposite directions. I've also driven the Rimac Concept One as well as the company's Pikes Peak racer, both of which used one motor per wheel. The hillclimb car weighed around 1500kg and the Concept One significantly more than that, but with Rimac's All-Wheel Torque Vectoring activated, both were as agile as cars weighing not much more than a tonne. They also had an amazingly positive way of getting from the apex of a corner to the exit, as though they were being yanked through on a wire. I haven't felt anything remotely like it in a car with a combustion engine.

Electric torque vectoring is exactly what gives me hope - even if only a glimmer of it - that the forthcoming generation of electric sports cars might actually be interesting to drive, rather than just unsettlingly fast. Of course, rescuing 90-degree drifts on an ice driving course, or spinning on the spot, is all well and good. It's up to car manufacturers to find a way to harness this amazing technology to make cars fun on the road in a way that won't get you arrested. It surely isn't beyond them. I don't know if an electric sports car with very clever torque vectoring will ever be as rewarding to drive as one with a howling petrol engine and a manual transmission, but I can't wait to find out.


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