MECAGLISSE, Canada — Four-wheel drive is almost as old as the automobile. But until recently, it was fairly crude and confined to trucks and vehicles like the military and civilian Jeeps.
The systems, for the most part, were part-time, which meant that they were suitable mainly for off-road duty and slippery conditions because they did not allow the front and rear wheels to turn at different speeds.
A few companies, notably Audi of Germany and Subaru of Japan, developed all-wheel drive systems that allowed different wheel speeds front to back and side to side. Audi's optional system, called quattro, is purely mechanical and requires no driver input. Subaru sells only all-wheel drive vehicles.
In recent years, beginning with luxury cars and crossover utility vehicles, there has been an explosion of AWD systems. Now every manufacturer in the world offers a version on at least some models.
As with everything else in the vehicle business, the AWD craze is extremely competitive, with companies elbowing to outdo each other.
An example is Acura, the luxury division of Honda, which has a new electronic system it calls "super handling all-wheel drive," or SH-AWD. Acura says it is the most advanced system anywhere and to prove it assembled its three SH-AWD models-the MDX and RDX crossover utility vehicles, and the RL luxury sedan in a demonstration against the Audi Q7, Mercedes-Benz E-Class, Lexus GS and BMW X3.
The event was held at Mecaglisse, an ice-driving facility about an hour and a half drive north of Montreal, Canada.
To level the playing field, the cars were equipped with the same snow tires, and all had automatic traction and stability control, which intervene by cutting engine power and selectively applying the brakes to get a driver out of a slippery and potentially dangerous situation.
All of the vehicles performed that function capably. But the Acuras' SH-AWD system, which uses two clutch packs on the rear axles to allocate power individually to the rear wheels to keep the vehicle on track around curves, allowed for more driver control. Audi calls it "direct yaw control" or "torque vectoring."
Although all of the AWD systems with traction and stability control will help keep a driver out of trouble, the Acura system makes for a more involved and entertaining driving experience. It should appeal to enthusiasts.