
UPDATE: As we expected, Mazda dropped a gorgeous, rotary-powered concept on us at the Tokyo motor show on Tuesday. It’s called the RX-Vision and Mazda hopes to make it real one day. We hope that...
-Fresh from its 2015 model update, the Toyota Prius C gets two minor enhancements for 2016. The most significant is something you may not be able to see, but it’ll see you. The Prius C is the latest Toyota model to be offered with Toyota’s Safety Sense-C system, which includes a low-speed pre-collision system, lane-departure assist, and automatic high beams. The system comes as part of the Deluxe Moonroof and Safety package on the Prius C Three trim level, and is included in the Upgraded Wheel and Safety package on the Prius C Four.
More obvious to the naked eye (which may wish it was shielded when it sees it) is the new “Persona Series” limited-edition model. Taking a page from the Scion Release Series playbook, Toyota is offering a limited, 1500-car run of black Prius C models with black wheels and “electric lime” or “cherry pearl” accents for the lower grille, headlight lowers, mirror caps (interior and exterior), and beneath the windows—basically the automotive equivalent of lipstick, eyeliner, and trendy sunglasses. Toyota has a different take on it, according to the press release: “You may have seen such paint schemes on customized exotics driven by pro ballplayers, but the effect costs far less on a 2016 Prius C Special Edition.”
--Whether you think the Prius C Persona Edition evokes pro ballplayers or something else altogether is your call.
--What It Does
-Splits engine torque into two outputs, each of which is able to rotate at a different speed.
Shortcomings
-When one tire loses traction, the opposing tire also experiences a torque reduction. In the worst case, your car is stuck with one wheel freely spinning while the tire with better traction can’t deliver enough torque to budge the vehicle. Modern traction-control systems compensate by applying the brakes (and thus a reaction torque) to the slipping wheel. That said, a more sophisticated diff is generally quicker-acting and more effective than this type.
Found In
-Anything without the pretense of performance or off-road ability—family sedans, crossovers, minivans, economy cars, etc.
What It Does
-With the diff locked, the connected wheels always spin at equal speeds. In sand, mud, and snow, a locked differential ensures that torque continues to flow to the wheel with higher traction.
Shortcomings
-Behaves like an open differential when not locked. Locking the diff on a high-grip surface such as dry pavement makes it difficult to turn the vehicle and can grenade the driveline.
Found In
-Jeep Wrangler, Mercedes-Benz G-class, Ram 2500 Power Wagon; optional on most full-size trucks.
What It Does
-A limited-slip differential marries the concepts of open and locked diffs, working like an open differential the majority of the time, then automatically beginning to lock as slip occurs. Lock-up can be achieved via a viscous fluid, a clutch pack, or a complex geartrain.
Shortcomings
-Purely mechanical limited-slip diffs are reactive. That is, they don’t begin to lock up until after wheelslip has occurred.
Found In
-Nissan 370Z with Sport package (viscous), Mazda MX-5 Miata (clutch type), Scion FR-S/Subaru BRZ (helical gears).
What It Does
-An electronically controlled clutch pack offers rheostatlike control between open and fully locked behaviors, with adjustments made hundreds of times per second. For example, if the computer determines there’s too much oversteer during cornering, it can dial in more lockup to stabilize the car.
Shortcomings
-As with a conventional limited-slip diff, torque is biased toward the slower wheel.
Found In
-BMW M3 and M4, Cadillac ATS-V and CTS-V, Chevrolet Corvette with Z51 package, Ferrari 488GTB.
What It Does
-Using additional geartrains to overdrive the half-shafts, torque-vectoring differentials fine-tune the torque delivered to each drive wheel. This produces a yaw moment that can slow or quicken the car’s rotation in a corner. Still confused? Read the damn story.
Shortcomings
-Torque-vectoring differentials are heavy, complex, and expensive, and inflict a slight fuel-economy penalty.
Found In
-Audi S4, S5, and S6; BMW X5 M and X6 M; Lexus RC F.