Before we had X-ray machines, doctors would merely amputate broken or infected body parts or cover the patient’s body with hungry leeches in order to suck out the bad spirits. Before we had automated production, children would work long hours making clothing in factories littered with severed fingers. And before we had desktop publishing, people would communicate by tying messages to birds, then covering the birds with wax and sticking them to pasteboards and running them through conventional printing presses. Or something like that. Anyway, times have changed.
Likewise, racing has changed. It used to be that when competitors wanted to sort out a suspension, they used trial-and-error methods, multi-sided dice and chicken bones in search of that elusive perfect setup. Now we have data acquisition.
Before we go any further into this discussion of data acquisition, let’s dispel the most common negative reaction people have when data acquisition is discussed. “Data acquisition is too expensive,” they shriek. Not quite. For the price of a couple of sets of tires, you can have a pretty trick setup that can give you more information than you ever dreamed of having for your car and you as a driver.
The Basics
First let’s back up a little. Just what is a data acquisition system? Simply put, a data acquisition system is any device that records and stores data for later interpretation. What data? Whatever you want, actually—speed, cornering forces, temperatures or anything that can be measured. This may seem oversimplified, but it really is just that easy.
The average data acquisition system is a box (computer) with various inputs. To these inputs can be wired various sensors and transducers that monitor various functions on the car. The information that these sensors record can then be dumped into a computer and analyzed at a later time.
There are two important considerations to remember when looking at data acquisition systems: One is the number of channels, and the other is resolution. Channels are the number of items the system can monitor. One channel can monitor one sensor or transducer. Most basic systems will have six or seven channels to start, and many are expandable to as many as 28 or even more channels. Resolution refers to the number of samples per second the device takes. A device taking 10 samples a second would be acceptable for recording the movement of a steering wheel on a superspeedway stock car, but not the shock movement on an Indy car. Some systems have programmable sampling rates for separate channels so you can personalize the data.
To learn more about data acquisition systems, we talked to Erik Kauppui of Corsa Instruments, whose 28-channel system is usually sold as a seven-channel starter set (more channels can be added, up to the total of 28). The basic system monitors lateral and longitudinal g, vehicle speed, throttle position, steering position, brakes and engine revs. Although this basic setup is typical, these parameters are fully user definable.
The data that is logged is output to a computer where it can be viewed in a variety of user-definable formats. Corsa's system can display accelerometer data in friction circles, bar graphs, or charts, as well as displaying other inputs as numerical or graphical displays.
Why Do I Need This?
"There's so much information out there toanalyze, data acquisition helps make it manageable” says Kappui. “It's an excellent tool for driver development, for gauging changes and finding the right setup. A good acquisition setup really maximizes every second of testing time." Truly, if the driver and crew are good communicators and are open minded to the truth, data acquisition can be the difference between winning and chasing one's tail.
With modern data acquisition, you can see the attitude of the car at every point on the track, as well as the inputs being made by the driver. Analysis of this data can show areas on the track where the driver is not using all of the car's capabilities, or possibly braking too early or late, or doing something to upset the car. It also allows you to see the effects of setup changes instantly and quantitatively.
Rather than gauging the effect of changes by subjective “feel,” data acquisition allows real analysis of those changes.
According to Scott Lehman of Pi Research, "The jump from a notepad and a stopwatch to even our most basic system is a huge leap. Greater even than from our basic system to our most advanced. While a stopwatch may show you lap times and a broad overview of the way your car is performing, only data acquisition can break that big picture down to a level where the performance can be analyzed.”
What Do I Need?
Good question. Basically, you'll need three things. First, you'll need a “box"—that's the data acquisition unit from the manufacturer.
Next, you'll need input devices. The data acquisition companies usually don't make their own sensors and transducers, but they can help you source them; many companies even carry popular applications. Finally, you'll need a computer. Most data acquisition companies use PC-based software—sorry, Macheads. Most companies can even help you source a laptop computer.
There is an option, though, for those of you who are not comfortable around computers. Northeast Microelectronics and Acquisition Systems have teamed up with their Datacam and Race Cam systems. Race Cam is a designed-for-racing video acquisition system that provides stable, vibration-free in-car video. Datacam is a device that overlays acquired data on that video. Datacam recommends the use of the Race Cam unit, but the camera can be customer supplied as well. The Datacam also has a computer output option. The real advantage of the Datacam, according to Acquisition Systems' Tom Henneka, is that it shows you many things with the video that no transducer can ever show. A picture is worth a thousand words, or a million bits of data in this case.
Actually, you may not even need that many sensors on you car. If you're wiring up a modern production car, you can use many of the stock sensors as input devices for your system. Things like engine rpm, throttle position, brake position and individual wheel speed (in many ABS-equipped cars) can be taken from existing sensors that are merely rewired for the data logger of your choice.
Pi Research's System 2 goes another step over basic data acquisition and includes a digital dash with 10 different screens. The next level of Pi systems has a fully user-programmable digital dash.
What’s It Cost?
Surprisingly little, actually. According to Corsa's Kauppi, you can set up a really nice system for less than $2000. You have to bring the computer, but the data logger, sensors and software are included in that price. For a video-based system like the Datacam, plan on spending about the same amount for the same number of channels, but you bring the video gear to the party.
When shopping for a system, you should discuss some of the following aspects with your potential system supplier. Ask them about the number of channels in the system. Can more channels be added easily? What's the maximum number of channels the system can handle? Discuss the resolution and maximum data storage capabilities of the system. A system that samples 400 times per second is useless if it can only record nine seconds of data. Is the sampling rate adjustable? And is the sampling rate of each channel independent of the other channels? Obviously the more options a system has, the higher the cost will be, and not all drivers will have the need for all the bells and whistles. Some drivers may want to start with a basic system and add channels and capabilities as their tuning and driving abilities demand. This is where an upgradeable system is important. If you have to scrap your existing system every time you want to upgrade, that won't be too cost effective.
Do I Really Need This?
That's up to you. According to Kauppi, “If the driver sees the system as a cop, there to watch over him or her, it's not going to help much. But a driver willing to take the data and learn from it, and sometimes swallow the ego, can really benefit.” Truly, data acquisition systems provide objective, clear information about what the car is doing. Some drivers have a hard time learning that they really aren't flat-footing through that kink, even when they'd swear they were.
The open architecture of these systems also allows lots of creativity in use. Basically, they can track whatever data you can think to put in them. "We didn't even know what tractor pulling was until some guys started buying systems for their tractors," says Kauppi. Henneka's Datacam has also been used for more than through-the-windshield viewing. “We've had cameras installed under hoods, pointing at suspension arms, shocks, bodywork, tires," he says. "This is stuff that the driver will never see, and it can't be accurately monitored from the pits, but with the camera, you can analyze what certain components are doing under different circumstances."
The Future
As cool as these systems are, most of the manufacturers we spoke with agreed that data acquisition for the club-level racer is still very much in the Atari 2600 stage. That is, it's affordable and cool, but the promise of the future is even rosier.
For a peek into the future of data acquisition, we can look to a couple of places: high-level racing and interactive military technology.
From the F1 and Indy guys, we can look forward to more proactive data acquisition software that helps catalog changes and can even "learn" different tracks and suggest setups. Through computer simulation of these various setups, the software may actually be able to experiment with thousands of different setups digitally before spitting out the one that produces the theoretical best performance.
From the military, we can expect different display options, such as helmet visor displays similar to those used by combat helicopter pilots (actually, this technology is a lot closer than you think to being affordable to the club racer).
Now let's imagine combining these technologies. Let's combine a learning computer, one that has analyzed the perfect braking, turning and acceleration points on a particular track and has adjusted the car to maximize these factors, with a helmet-mounted display that shows the driver the ideal line and signals at braking and turn-in points (advancing the signals to compensate for the driver's reaction time, of course). That can be combined with an in-car video system that analyzes the lines of the traffic it sees and plots high-probability passing areas. Spooky, huh? All this technology (plus stuff they aren't telling us about) exists, so it's only a matter of time before it's affordable.
Conclusion
We've come a long way from the stopwatch and the notepad, but the idea is still the same. By boiling performance down to numbers and charts, driver and crew can eliminate opinions from the equation and judge objectively whether a change actually made a difference in performance. And with prices of data acquisition systems, like those of most other computer products, reaching affordable levels, this is no longer the high-tech toy of the elite; it's becoming the required tuning tool of the masses.
Like what you're reading? We rely on your financial support. For as little as $3, you can support Grassroots Motorsports by becoming a Patron today.
