TurboTravis

Simply put, what does it do when it sees wheelspin? Cut throttle/fuel/timing etc?

Thanks
Travis

Bill Dearborn

It will do a combination of things to reduce wheel spin. Some times it applies the brakes, some times it cuts torque and some times it applies the brakes and requests the PCM to cut torque. It all depends on the situation (speed, car yaw, one wheel slipping, etc) you are in.

Bill

TurboTravis

How does it cut engine power? Cutting the throttle? Spark? I'm just trying to verify that it does NOT ever lean the engine out to cut power...

AlwaysInBoost

it will close the throttle... I've seen my boost gauge go from positive manifold pressure to near ZERO vacuum while the throttle was to the floor and TC was fully enguaged.

taken from the FAQ at the top of this forum:

Traction Control
As noted earlier, Active Handling works in conjunction with the traction control system, and for 2001 that part of the system has been much refined. A new control philosophy of targeting specific rear brake pressures and modulating engine torque around those points has resulted in fewer engine sags and superior vehicle acceleration when compared to the 2000 system. This new calibration allows drivers to enthusiastically experience Corvette's power and handling while still maintaining control over excessive wheelspin. Average drivers may now elect to leave the traction control system on when navigating autocross or gymkhana courses.

Competitive Mode
Corvette's Active Handling system has a unique feature called Competitive Mode, which allows the driver to disengage the car's traction control feature without giving up Active Handling's other benefits. Holding down the Active Handling button on the center console for 5 seconds enables Competitive Mode. This feature recognizes that, at the hands of a highly skilled driver, a bit of rear wheelspin may actually be desirable in autocross or other racing events. In previous years, it was necessary to bring the vehicle to a full stop to enable Competitive Mode. But for 2001, this requirement has been eliminated.

The Corvette's 2001 Second-Generation Active Handling system is smarter, less intrusive, and more adept at making the total driving experience precisely what Corvette owners have come to expect from their cars.

All Corvettes have the second-generation Active Handling system as standard equipment. The system features dynamic rear brake proportioning to prevent rear wheel lockup; rear brake stability control to assist the driver in maintaining control under light braking and high acceleration conditions; integral traction control calibrated to allow drivers to experience the vehicle's power and handling while maintaining control over excessive wheelspin. It also has an on/off switch and a "Competitive Mode" which allows the driver to disengage the traction control feature without giving up Active Handling's other benefits.

also see:
http://www.c5registry.com/zo6/Performance/AGILITY.HTM

Bill Dearborn

Here is the description form the Service Manual:
When drive wheel slip is noted while the brake is not applied, the EBCM will enter traction control mode.

First, the EBCM requests the PCM to reduce the amount of torque to the drive wheels via the requested torque signal circuit. The PCM reduces torque to the drive wheels by retarding spark timing and turning off fuel injectors. The PCM reports the amount torque delivered to the drive wheels via the delivered torque signal circuit.

If the engine torque reduction does not eliminate drive wheel slip, the EBCM will actively apply the drive wheel brakes.

You can call shutting off fuel injectors as leaning the engine but it is for a very short time period. No longer than it takes to get the wheel to stop slipping. On my car I have noticed that sometimes it seems the EBCM actually applies the brake first before getting a torque reduction. If I let the clutch out at 2300 rpm with the car straight a lot of times the rear wheels will lightly spin as the car accelerates and the system uses the brake to keep the car straight. It will do this through first and into second. However, once I hit third hard at 70 mph the TC will cut power for an instance if one of the wheels slips when I shift.

Bill