Tech: Inside the Latest Davis Traction Control Technology
In recent years, the sport of drag racing has witnessed a new transformation across many top-tiered racing venues through technology known as traction control; forever changing how we viewed the once-taboo methodology, for keeping our tires planted safely on the race track. Today, race teams all across the vast spectrum of the sport, are using these systems not only in competition, but in testing to help improve their race day setups. Davis Technologies is at the forefront of this movement, bringing a wealth of experience and knowledge from the dirt track racing world, and transforming drag racing applications across the globe.
The Power Automedia team got its hands on one of Davis Technologies’ most fully-featured traction control systems – the TMS Drag Pro MAP – for testing on our Project BlownZ 275 Radial Camaro in the 2013 NMCA West series. Combined with their DTR-3000, the Davis Handheld Programmer, and their driveshaft collar and driveshaft sensor, we are geared up for the full Davis Technologies experience.
In this tech feature, we’ll be reviewing the Davis system on our Camaro, with an in-depth look at each of the components, how the system works, and the ways that teams are utilizing traction control to better their racing efforts. And to help us, the outspoken traction control guru behind Davis Technologies, Shannon Davis, will share his thoughts and his knowledge. In part two, we will share the results.
The Davis TMS Drag Pro MAP
Davis Technologies boasts their TMS Drag Pro MAP as the most advanced self-learning traction control system on the market today. With incredible accuracy, and adjustability that allows fine tuning down to the nth degree, they’re not kidding.
The TMS Drag Pro MAP was designed with the professional level racer in mind, including multi-stage corrections to cut power with more precision than a single stage unit, offering racers the ability to get more aggressive with their setups. The unit features a 0-5 MAP volt output signal that can be plugged into your existing boost control curve in your ignition box, or an ECU to read the signal and call the timing reduction. Essentially, the 0-5 volt signal functions just like a MAP sensor would.
The Pro versions of Davis’ systems include extended tuning options, offering adjustment of the retard for different parts of the track, and zones to adjust how aggressive the system is early versus late in the run. These professional-grade systems also provide a versatile software interface from your ride to your PC, or an optional Handheld Programmer for convenient real-time access to key in these variables.
One of the key elements of the TMS Drag Pro MAP is the built-in self-learning technology, which Shannon Davis explained in detail for us, by comparing it alongside a non-self learning unit.
The Dials: What They Do
%Cut: This is the maximum percent of retard that the unit is going to deduct in a percentage value of the maximum retard you’ve set on the DTR-3000 or the ECU. This allows you to adjust the maximum amount of timing you want to take out on a particular track
Ramp-In: This is how quick the system is going to put the timing back at its normal curve once the spin is gone
Threshold: According to Davis, one will likely never use the threshold setting, but if you turn the dial from the ‘SL’ to positions 1-9, it becomes a non-self learning unit, which isn’t something anyone typically does
Mode: This sets the overall sensitivity, in terms of how big of a deviation from the learned rate it’s going to take for the system to trigger. In essence, mode allows you to set the amount of desired intervention.
“A non-self learning system is monitoring the rate of acceleration and looking for a change above a certain threshold that you set. If you set the driveshaft speed to 1,000, for example, anything over that speed, and it will retard. It’s similar to what guys used to do with their dots, and other manual marker methodologies. The self-learning feature, on the other hand, is monitoring the actual rate of acceleration of the car, and looking for deviations from that learned rate, according to the size of deviation you set. So it’s not just learning a slip or rate of acceleration above a pre-set limit. It is also calculating a percentage of change above the rate, and it updates that rate every driveshaft revolution.”
As Davis put it, there’s no reason for your car to suddenly accelerate 25% higher in 1/8 of a turn of the driveshaft than it did on the average on the last turn. The system intuitively looks at how long the last 1/8 of a turn took, and compares it to the average 1/8 of a turn over the last revolution, and adjusts accordingly.
The DTR-3000 – short for Digital Timing Retard – is designed for systems that don’t have a boost retard input, and is placed between the crank trigger and the ECU, or between the ECU and the ignition box to provide a 0-5 volt referenced retard. On our BlownZ, the DTR-3000 acts as the input for the TMS Drag Pro MAP, and sits between our MSD PowerGrid and our MSD ignition box.
The DTR-3000 is largely an input-output system, and contains an adjustment control for reducing the maximum retard, up to 5 volts. It can be set at a maximum of 5 volts and 2.5 degrees, for example. Then on the Davis box, you have 10 increment settings between 0 and 5 volts. This can be set up to change in quarter degree increments — anywhere from 2.5 to 20 degrees of total retard over the 0 to 5 volt sweep.
Traction Control in the Palm of Your Hands
While your adjustments can be handled via the dials on the Drag Pro MAP box, often the said box is tucked away under the dash, or mounted on the firewall, where access is difficult. To alleviate this little problem, Davis offers a Handheld Programmer that plugs directly into the box, allowing you to fine tune all of the aspects of the traction control with ease.
With this serial interface programmer, you can adjust the driveshaft RPM at which the system becomes active, and the speed it turns off. You can also define the “null zone”, or the window of driveshaft RPM, where the unit can be set to reduce a lesser amount of power or make no correction at all.
For those technically inclined, these programmers are available through a secure wireless Bluetooth connection for a few extra bones.
Driveshaft Collar And Sensor
This entire system is of no use without a way to monitor and measure the revolutions of the driveshaft as the car goes down the race track. The Davis system accomplishes this through the use of a driveshaft collar (or “trigger wheel”), and a sensor that is mounted on the driveshaft itself. The collar ring contains machined steel teeth that are picked up by the Davis sensor eight times every revolution, which Davis explains, is far more accurate than using a magnetic field.
“We know that the sensor is going to trigger right on that machined edge, not here versus there because one magnet is stronger than the other,” explains Davis.
The ring can be placed inside the rear-end housing to count pinion teeth or ring gear teeth, or placed inside the transmission to count the teeth on the parking brake “dogs”.
The sensors have multiple outputs so that one ring sensor can trigger three or four things, be it the Davis box, the engine management system (i.e. – BigStuff3), a Racepak and other systems. One sensor can trigger them all.
How It Works
The current ecosystem of our ignition and traction control system, centers on the use of MSD’s 7730 PowerGrid programmable ignition controller. Working with the 7730 box, the Davis system offers more precise operation and virtually infinite adjustments. Let’s take a look at the Davis system out-of-the-box setup, and how it works.
With Project BlownZ, we’ve set up our new Drag Pro MAP box on the electronics plate, on the floorboard of the passenger side of the car, where the two MSD modules, the DTR-3000, our FAST XFI system, and other electronics are situated. Moving to the back of the car, we’ve placed the driveshaft collar between the yoke and the differential, and the sensor is wired back through the car to the Drag Pro box.
With the self-learning functionality onboard, the Davis system eliminates much of the initial trial-and-error process of finding a clean baseline. Reducing the time to plot our points out of the equation, means more controlled runs before the race weekend is over.
The self-learning system monitors how fast the car is accelerating, looking for any sudden deviation, or sudden slippage. So it doesn’t care if it leaves the line crawling like a snail or hauling ass, as long as its doing it smoothly. – Shannon Davis
“The self-learning system monitors how fast the car is accelerating, looking for any sudden deviation, or sudden slippage. So it doesn’t care if it leaves the line crawling like a snail or hauling ass, as long as it’s doing it smoothly. As long as you can get the car to launch and get it to leave, our system monitors what it’s doing and looks for sudden changes above that,” explains Shannon Davis.
The First Hits
On a radial tire car like BlownZ, Davis suggests we hit the track with the Drag Pro MAP set on ‘Mode 2′ and make our first hit. “The timing can be adjusted slightly to conform to the setup of the car,” as Davis explains, “but this would only be a minute adjustment you would make as you complete runs, and gain data that displays the points on the track where slippage occurs and whether the car needed more or less timing to cure the slip.” Because the Davis systems (even the non-self learning systems) operate on a sudden change from a rate, the job of actually plotting the rate is eliminated.
According to Davis, with a blower car, the maximum amount of timing you might want to reduce is 10 degrees on a bad race track, with 5 degrees the more practical expectation. To make this adjustment, we simply turn the dial 5 degrees in the DTR-3000, and then using the “% Cut” dial on the Drag Pro MAP, we define the percentage of that maximum value that we want the system to pull out. This can be set anywhere from 10-100%. So if we set it on 50% of five degrees maximum, it will pull out 2.5 degrees of timing.
The “% Cut” allows the driver to adjust the maximum timing based on the race track conditions. It might take more (or all) of that five degrees on a hot, sloppy track, while it may require just one or two degrees (20-40%) of that maximum on a good track. The maximum on the DTR-3000 can be set at 10 degrees or even 20 if you so choose, but that will make each click of the “% Cut” equates to two degrees of timing, which would be a big change on a blower car and certainly a lot on a nitrous car, as Davis explains.
Interpreting the Data
With everything properly set up and in place, the next course of action is a turn on the track to make our first hit. Although it may appear to be a good, clean run, we may notice on our Racepak data that the car is encountering some slip following the first to second gear shift, pulling the full 2.5 degrees of timing, admittedly a bit too much.
“In this occurrence, you can use the Handheld Programmer to tell the unit that after a certain driveshaft RPM, I don’t want it to take out any more than 1.5 degrees,” said Davis. “This keeps it from overcorrecting, and allows you to limit the max retard in different zones of the track.”
The Null Zones
On a trial run, we may have 3 degrees of timing set on the unit, and during that spin at the first to second gear change, we might notice that the 3 degrees is a bit too much to correct the slip and slows the car down. Using the null zones setting, we can program the 3 degrees through the gear shift and the slip after the shift, but then from 4,700 RPM driveshaft speed on down, only take out 1.5 degrees — half of the controller setting. The unit can also be set to shut off at a certain RPM down track, where the removal of timing is likely to have more of an effect on the elapsed time than a bump in the track will.
“We’ve had situations at certain tracks where there are bumps in the last 100 feet of the racing surface where the traction control is coming on, leveling out the engine RPM and the G-meter, and killing the trap speed. They were spinning the tires, but the cure was worse than the disease,” explains Davis. “Personally, I’d like to have a little traction control if I’m sliding around, but we leave that up to each individual racer.”
We’ve had situations at certain tracks where there are bumps in the last 100 feet of the racing surface where the traction control is coming on, leveling out the engine RPM and the G-meter, and killing the trap speed. They were spinning the tires, but the cure was worse than the disease. – Shannon Davis
Shannon Davis and company have spent years testing and analyzing data to create the proprietary algorithms that work behind the scenes in their traction control units. In essence, the current systems work on sort of a dual stage operation, with both a small correction and a large correction methodology intuitively built in. A large correction occurrence would be the result of a 5 degrees of timing dialed in via the “% Cut”, and the system actually utilizes that maximum of 5 degrees if the driveshaft speed reaches a high rate of driveshaft RPM over the learned rate. In a situation where the tires are spinning but not in excess, the system will go with the small correction methodology, which would be half the maximum, or 2.5 degrees. However, the system won’t automatically pull 2.5 degrees, but will ramp up to that maximum if need be. If it climbs to 0.5 degrees and that’s enough to fix the tire spin, it will ramp back down.
In addition to the two zones, or stages (the small correction and the large correction), the unit has a defined zone for a start RPM zone and another to simply shut it off. The start RPM is the point where the traction control won’t come on until a specific driveshaft speed, and once it reaches that, it will begin pulling the small or large corrections.
The sheer speed of the Davis systems does away with situations where plots are missed in either direction, and timing changes relative to the driveshaft speed are too much too late, or not enough at all. The Davis system picks up the driveshaft in 1/8 of a turn and generally pulls one to three degrees to calm the spin before it eases back into its normal timing curve. This is an example of where the “Ramp-In” feature of the Drag Pro MAP comes in, as you can also define the rate at which the power is ramped back in from a change.
Anything but a Cheater’s Device
Before companies like Davis Technologies, and racing sanctions like the ADRL brought credibility to traction control in drag racing, these systems were unfairly labeled the tools of a cheater, and truth be told, if you were to run one today at a venue where it’s not permitted, you would be a cheater. But the rules say nothing about its use during testing, and that’s where many teams — some you wouldn’t even suspect — utilize this tool, today.
Davis explained to us that many of his customers are race teams that compete in classes, where the use of these systems, are prohibited. However, those same teams will often install his traction control system during test sessions, where they can utilize it as another data sensor in the race car.
The first drag racing system we ever did was actually developed for and went on a nitro Funny Car, and it worked great. – Shannon Davis
“They don’t have a rate of acceleration sensor that they can buy from anyone else, so they use it to see if there’s some information they can gain from it,” said Davis. “They may have it set up where it’s not actually coming on, or doing anything to the car, but just showing them where the tires were in trouble. Generally, the data it reports helps them identify factors like tire temperature, shock travel, the G-meter and other sensors, to back up what they’re feeling on the track. The smart guys take that data and benefit from it.”
Those that utilize traction control to varying extents, include Pro Modified teams, small tire doorslammer competitors in growing numbers, and even some of the top nitro teams in the sport.
Davis added, “The first drag racing system we ever did was actually developed for and went on a nitro Funny Car, and it worked great.”
As we’ve illustrated here, traction control is no longer the taboo subject it once was, nor is it as technologically challenging as it may appear to be on the surface. The technology, what it can provide you with on the track, and the valuable data that it can deliver to you off the track, is transforming racing, and why traction control is here and here to stay. And, if you were to ask Shannon Davis, he’d candidly tell you that these systems have only scratched the surface of what’s possible for the future.