I mashed the Corvette's throttle in a blatant attempt to overcook the rear tires on the tight, uphill, left-hand bend at Grattan Raceway in Belding, Michigan. This would've normally provoked a broad, sideways slide with a full opposite-lock steering correction. Dramatic-looking, but neither stable nor particularly fast. But instead of swinging out the rear end as I maniacally floored the gas, the car braked smoothly, pivoted slightly, and held a crisply arcing line as I gently countersteered. Talk about the unfair advantage.
From far off under the hood, I could hear and feel the rapidly cycling hydraulic valves. And though I may have appeared the hero, I knew the Corvette's new "Active Handling" system actually had just saved me from embarrassment, or something far worse.
The point is that Active Handling did it automatically by slowing the car and then selectively activating individual front and rear brake calipers to twist the car back onto the proper cornering line, given my speed, steering angle, and the amount of grip available. And though it sounds like black magic, it has more to do with black boxes stuffed with microchips and clever algorithms.
But it won't save a Corvette-driving idiot. "It's calibrated to follow the driver's commands," explained Mike Rizzo, a Corvette development engineer. "If you steer it into a ditch, it will go there."
Active handling detects and corrects unwanted vehicle maneuvers. Inputs to the control computer are provided by a steering-angle, yaw-rate, and lateral acceleration sensor. (Yaw is the vehicle's propensity to rotate about its center. Picture a pin punched through the car's top and into the ground. A lateral acceleration sensor measures the amount of centrifugal force created in a turn.) The system also taps into the anti-lock's wheel-speed sensors, the traction-control system's sensors, and the powerful brake hydraulic circuits.
This system can reach into a poorly executed driving maneuver and help reduce either excessive understeer or oversteer. But unlike earlier stability control systems, its software has been carefully written to avoid engaging too soon, where it might interfere with the sporting feel of the Corvette.
It goes into action only when the car's limits have been exceeded. In other words, the system activates only when there is a significant difference between how the driver intends (via the steering-angle sensor) for the car to corner and how the car is actually cornering.
And since some Corvettes are driven occasionally on the racetrack, there's a "competitive driving" mode that deactivates the traction control system. Although the stability system's sensors and wheel-braking hydraulics are still armed, moderate wheelspin for added acceleration and cornering corrections (oversteer) is available without throttle relaxing, ignition timing bumps, or brake applications to spooling rear wheels.
Remarkably, this option JL4 will cost a mere $500 when it becomes available in early 1998. (It will be standard on convertibles with the Indy 500 Pace Car package.)
Obviously, we were extremely impressed with the system's capabilities. However, as one Corvette development engineer put it, "It's a fabulous system, but it's not capable of finding traction that isn't there. At some point, physics takes over."
That said, beyond anti-lock braking and traction control, there's electronic stability control. Now, beyond even the state-of-the-art stability control systems from Cadillac, Mercedes-Benz, and BMW, there's the Corvette's Active Handling option.
As noted, the system can also be switched off. But unless you're Juan Manuel Fangio, it's really best to leave it on.