Once considered the sole province of large commercial aircraft, data recorders have moved to the drag strip. By most measures, nearly all serious drag racers now use the so-called “black boxes” to record fuel pressure, oil pressure, shock travel, engine rpm, clutch rpm, acceleration and a host of other parameters.
“We use it on every part of the race car,” says Jimmy Mock, a “Pro Street-Level” drag racer on the West Coast. “I wouldn't even attempt to race without it.”
Indeed, most drag racers now see data logging as the difference between success and failure. With today's pro-level racers turning quarter miles in under 4 sec, with their 0-60 mph acceleration time hitting 1 sec and with their engines soaking up more than a gallon of gas per second, time is of the essence. Data recorders provide that time advantage, in many cases enabling racers to slice one- or two-hundredths of a second off their elapsed quarter-mile time (ET), the gold standard of drag racing.
“It has huge benefits,” says Roger Conley, vice president of marketing and sales for Racepak Data Systems Inc., a maker of data-logging products. “Without data recording, it's all trial and error. And it's a very subjective form of trial and error.”
Filling Information Gaps
Trial and error, of course, once served as the main form of evaluation and design for drag racers. During the mid-1980s, however, electronics' manufacturers saw a niche market opportunity. Racepak, among others, rolled out data recorders with one channel, which printed results on old-fashioned thermal paper.
Data-logging capabilities have since followed a path of exponential improvement, paralleling the rest of the electronics' industry. Today's systems incorporate dozens of channels. Some employ vehicle sensors that are linked to central processors by high-speed databuses.
Racers say they need data-logging capabilities for two reasons: First, because their competitors have them; second, because data loggers enable racers to better understand what's happening under the hood during the course of a race.
“It takes the guess work out of evaluation,” Conley says. “If you make a run without a data collection system, you'll be given a slip of paper containing your incremental times. And that's all you'll have to go on.”
Experts say the data systems fill in the gaps between those incremental times. Since most tracks provide ETs only at 60, 330, 660, 1,000 and 1,330 ft, racers use the data recorders to make sense of everything that happens in between.
“Without data logging, you wouldn't know what happens between those data points,” Conley says. “With data recording, the driver can tell where the car went slower and why.”
Gathering Race Data
Data loggers accomplish all that with a combination of sensors, software and fast computers. RPM Performance Products, for example, uses pressure transducers from Setra Systems Inc. to measure fuel pressure, oil pressure, shock travel and so-called “boost pressure” from turbochargers. Pressure sensors for such applications are mounted near the engine or the shock absorbers. Typically, the sensors send their signals through discrete wiring to an extruded aluminum enclosure containing a surface-mount printed circuit board incorporating a microcontroller from Microchip Technology, Inc. A few minutes worth of analog vehicle performance signals — taken at speeds ranging between 100 and 1,000 samples per second — are converted and stored in a Cypress SemiconductorEEPROM for subsequent download to a laptop computer. RPM typically incorporates relatively small memories — ranging in size from 512K to 2 Mbytes — because the duration of information-taking is so short.
How much gasoline do dragsters burn?
Consider this: It takes approximately 15 sec to pour out the contents of a common, plastic, 1-gal container of water.
High-level dragsters suck fuel at approximately 15 times that speed, often reaching a gas consumption rate of about 67 gpm.
The result is an extraordinary level of power. Top alcohol dragsters generate about 3,000 hp. Zero-to-60 mph times are often less than a second.
“We have enough memory on board our data loggers to record about two minutes of data,” says Randy McMahon, president of RPM. “And we can partition the memory for 32 separate runs.”
Radiated electrical noise serves as a problem for such data recording, however. Alcohol funny cars employ high-powered magnetos, causing noise problems for sensors, especially those mounted near engines.
“It's probably the most difficult environment anywhere for electronics to function,” McMahon says. “It can scramble a laptop from 10 feet away.”
Shielding and ruggedness have combined with size reductions to put pressure transducers on the map for drag racing teams. A decade ago, says Mike Guerra of Setra Systems, pressure transducers were too bulky for some drag racing applications.
“When we came out with a lower cost, smaller package,” Guerra says of the company's 3100 Series pressure transducers, “we started to have good luck with it in data logging.”
Other types of sensors have also had an impact on drag racing. RPM, for example, employs a solid-state ADXL05 accelerometer from Analog Devices to measure vehicle acceleration. Racepak, meanwhile, uses its own brand of Hall Effect sensors on the input to the vehicle's differential, thus enabling monitoring of such variables as driveshaft speed and clutch rpm. Racepak's technology also uses a thermocouple-based system from Exhaust GasTechnologies to track exhaust gas temperature.
Racers say the value of data logging goes beyond vehicle performance. By tracking such parameters as oil pressure and fuel pressure at each cylinder, race teams can monitor the relative “health” of their vehicles.
“With a blown alcohol car like ours, a mistake could mean a burned piston,” says Mock. “Theoretically, we could be replacing wrist pins and rings, if not the pistons themselves.”
Mock's team also uses Racepak's data-logging systems to monitor the health of other components, from crankshafts to clutches. “Being able to compare engine rpm to clutch rpm, you can figure out the percentage of slip,” he says. “And knowing the percentage of slip, we can figure out how much life we can get out of our clutch discs. Without data logging, we'd be guessing.”
Suppliers say such diagnostic advantages are only beginning to be fully understood by customers. “The diagnostic side is the part everyone leaves out,” Conley adds. “It's the side that no one wants to talk about because it doesn't have the 'flash.' It doesn't have the pizzazz.”
Companies such as RPM and Racepak, however, may provide their most important service through software programs that help with diagnostics and performance. RPM, for example, offers software called RPM Pro that includes a graphics package for examining data on-screen. The software displays performance with respect to time, overlaying variables, such as crankshaft rpm and acceleration, on the same time scale.
Similarly, Racepak's V300SD system uses a CAN (controller area network) databus to deliver sensor information to controllers, which then record the data onto a secure digital (SD) Flash memory card like those used in cameras. The memory card allows users to easily transport data to their PCs, where software analyzes it for subtle performance changes. Signals from thermocouples, for example, can be used to better understand an engine's issues.
“We can pick up an engine misfire,” Conley says. “It appears as a dogleg on the graph.”
Racers say the move to data logging is gaining favor, even among novices who bring Dad's Blazer to the drag strip. Those who truly want to win, they say, are being drawn to data logging by virtue of the fact that competitors are using it.
“Once they have it, they never want to run a car without it again,” Conley says.
Moreover, the trend is clearly moving to production vehicles, as well. The Institute of Electrical and Electronics Engineers (IEEE) has produced standards (such as IEEE P1616) for “motor vehicle event data recorders.” It is hoped such standards will help electronics makers develop the “black boxes” for autos, trucks, buses, ambulances and other vehicles. Several non-automotive companies, including IBM, have joined in efforts aimed at using the recorders to create a system for electronically collecting, transmitting and depositing crash information into giant databases.
Still, the desire to use data recorders may be strongest in the world of drag racing. Suppliers say they expect it to stay that way for a long time.
“At the end of the day, these racers are trying to gain as much traction and apply as much power as they can in a quarter-mile,” Conley says. “And they'll use every available tool to do that.”