Traction control systems are the subject that nobody really wants to talk about in racing. But that doesn’t mean they don’t exist, and in many dirt track racing classes they are even legal. We wanted to find out more about what exactly is going on and how they work.
Shannon Davis is the owner of Davis Technologies, one of the leading manufacturers of affordable traction control systems for all types of race cars. Most of Davis’ business comes from systems designed for sports car and drag racing, but he also has developed traction control systems that work well for oval track racing on dirt.
“It’s just another tool in your toolbox,” he says. “Traction control isn’t going to turn a bad driver into a world-class champion on a dirt track, but what it will do is help a good driver get the most out of his car. It won’t do much to help the new driver or a bad driver who just wants to mat the gas pedal and turn left. You can overpower the system, so you’ve still got to go out there and drive like you’ve got some sense.”
Davis also contends that traction control shouldn’t have the stigma that many in oval track racing have attached to it. “It is comparable to a cam change, or an ignition change to help the driver keep from spinning the wheels accelerating out of the turns,” he says. “You can build a motor for maximum power, and it can just be crazy responsive really difficult to drive. So the smart engine builder will do something with the carburetor linkage, or he will make a cam change, or do something to help calm that motor down so it is easier to drive. And everybody is like, ‘Hey, great idea!’ But if you do it electronically, that is some sort of mortal sin.
“It’s really all the same thing,” he continues, “but I think it’s because people understand the camshaft and carburetor and stuff like that, and they don’t understand electronics.”
Davis Technologies’ traction control systems work by monitoring the crankshaft speed and picking up any acceleration spikes as soon as they happen. Since the rear wheels are directly connected to the crankshaft, a sudden acceleration at the crank means the rear wheels have broken traction and are spinning. The system can actually measure crankshaft speed on circle track cars as fast as every one quarter of a turn of the crankshaft, so it is capable of detecting wheel spin practically as soon as it happens.
Once the box has detected a spike in crankshaft rpm, which probably means the rear wheels have broken traction, it makes a correction to reduce slip by retarding the engine timing. This kills the power to the rear wheels and helps regain traction. But to keep the engine from lugging from a big power loss, Davis’ system can actually work so quickly that it retards ignition timing on a cylinder-by-cylinder basis. As soon as the rpm spike at the crankshaft is under control the engine is returned to optimal timing, and it happens so fast that it is barely noticeable.
Of course, traction control is pretty straightforward in asphalt racing where tire slip is really never a good thing, but in dirt track racing drivers control the car with the throttle practically as much as they do with the steering wheel. Davis, however, says that this isn’t an issue, especially with his self-learning systems which learn the average rate of acceleration of the drive shaft and adapt lap after lap.
There is also an option to tune the system to your needs. The traction control unit has an adjustment called “mode” that sets the system’s sensitivity to tire slip. Racers can adjust the mode to correct for larger slips while not reacting to smaller levels of tire slip which can be useful in dirt track racing.
“The mode control has sensitivity settings,” Davis explains. “It is (a scale) between one and eight. The real world settings are four, five and six, which is where most people are going to be. Seven is if you are really bad and need a lot of help from the unit, and three is if you just need a little help. So the sensitivity is how often or how likely the unit is to come on. You set the sensitivity to match your driving style.”
Installation of the control module, it turns out, isn’t that difficult. The unit uses a simple three-wire hookup. One wire goes to a power source to power the box, a second naturally goes to ground, and the third is spliced into the wire lead from the distributor to the race car’s ignition box to monitor the signal that controls the spark. “If you can maintain a race car, then you can install the unit,” Davis says. “I’ve never had anybody in my 17 years that couldn’t handle the installation.”
Overall, Davis makes a strong case that traction control systems should be more widely accepted in dirt track racing. He points out that fuel injection–and all the computer controls that come with it–are already gaining traction in racing. And the costs aren’t actually as prohibitive as some would make it sound.
“Technology surrounds us,” he says. “It is a part of all of our lives. We have a traction control unit that sells for $2,195, and dealers are selling them for like $1,895. Everybody with a race car can swing $1,895 every five or 10 years. Think about what it costs if you get loose and scrub up against the wall one time–especially if you break an axle and bend a hub. That stuff is going to happen anyway, but if you can minimize that and get the whole field running a little more competitive, then I don’t see the harm.
“Basically, traction control is just another tool. If you can use it to benefit your racing and put on a better show for the fans in the stands, I think that’s a good thing.”