While every part of a performance car serves a purpose both aesthetic and functional, there are certain parts, like the differential, that are absolutely essential. The differential — the ability of the wheels to spin at different speeds at one time — can also make or break the performance driving experience.
An open differential solves the problem of two wheels traveling at different speeds around a corner (the outside wheel goes around a larger circle than the inside and has to spin faster), but this can create other issues for the performance driver. If one wheel has less grip — on a wet surface, for instance — it can spin freely. That means all the power will go to the wheel with no grip, and progress becomes difficult. With a powerful car like the Jaguar F-TYPE R Coupe on the track, an open differential makes it hard to use all 550 horsepower coming out of a corner without spinning the inside tire and losing precious time.
The classic way to counteract the negative side of an open differential is with a limited-slip differential, which locks the two driven wheels together when their speed differs by a certain amount. But a limited-slip is still a compromise — when it's locked, the car is more stable, but also less maneuverable. What if, then, you could lock and unlock a differential whenever you wanted, or even vary how tightly the differential locks? That's the idea behind the F-TYPE's Electronic Active Differential (EAD). Instead of locking up based on a set of static conditions (such as wheel speed), a computer-controlled clutch precisely controls the actions of the rear axle based on parameters like throttle, steering, braking, and the speed of all four wheels.
In practical terms, the F-TYPE R Coupe precisely manages the torque for each of the rear wheels (and it's further helped with the addition of the torque-vectoring-by-brake system). Coming into a corner, for example, the F-TYPE might leave the differential open, for the kind of instant handling responses you'd expect from a car with a leaping cat on the cargo lid. As you get back on the gas, the differential dials in just enough locking to use the maximum amount of accelerative grip from both of the rear wheels, allowing you to use more throttle on the exit of a corner alone, which will maximize those precious tenths on a lap. And it also adds stability by keeping the rear wheels planted in cresting corners like Turn 10 at the Circuit of the Americas, and can go from completely open to completely locked in only 200 milliseconds, via an electric motor acting on a multiplate clutch.Less sophisticated sports cars might get hairy in such situations. In the Jaguar, you can just focus on driving and trust that the car will stay predictable.
Of course, if you're into some hoonage — like former Stig Ben Collins weaving and drifting through the field of Jaguar Performance Driving Academy participants in this video, the F-TYPE R Coupe will definitely maximize the fun.
Mike Austin is the Director of Creative Strategy for Tiny Toy Car. He was previously Automotive Editor at Popular Mechanics and Technical Editor for Car and Driver. He lives in Michigan with a Buick Roadmaster Wagon.