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Distance = Speed x Time - data logging a Top Fuel dragster
25.1.06. It’s one of the most fundamental equations of physics, and in its various forms, allows you to calculate any one of the variables – time, speed, distance or acceleration – as long as the other two are known. It is also the basis of every form of motorsport devised by mankind, as the essence of competition, whether on land, sea or in the air, is to cover a given distance more quickly than your rivals.
The mathematics involved is straightforward enough if the speed remains constant over a known distance or for a measured period of time. It becomes a little more complicated if the speed element varies. Needless to say, motorsport revolves around the dynamics of acceleration and deceleration. It therefore seems self-evident that to be able to measure both extremely accurately, along with maximum speed, elapsed time, and distance covered, correlate all of that with other relevant inputs, such as vehicle throttle and brake position, wheel speed and yaw angle, and then review all of the data quickly, would be an invaluable tool for teams looking to optimise the performance of their machines, and competitors looking to optimise their personal performances.
As a form of motorsport, drag racing is undoubtedly the most basic expression of the speed, time and distance equation. It is about covering a measured distance – a quarter of a mile – as quickly as possible. There are no corners, no artificial chicanes, no pit lanes to negotiate. It is just a flat-out blast, from a standing start, with the aim being to reach the finishing line before the competitor running in the lane alongside you. Simple? In concept, yes. In execution, not at all.
Wildside's top fueller
In 2003, Datron Technology Limited, a company specialising in producing equipment for measuring speed and distance, fitted its 2D data-logging system to the Wildside Inc Top Fuel dragster during a June meeting at Shakespeare County Raceway, near Stratford-on-Avon, UK. As those who follow the sport will know, Top Fuel dragsters are as brutally functional as any jet fighter. There is absolutely nothing fitted to one of these cars superfluous to its sole reason for existing, which is to cover a measured quarter-mile of tarmac as quickly as possible.
The Wildside car is typical of current Top Fuel cars, its pencil-slim, 33-ft long silhouette based on a custom-fabricated, tubular chassis clothed in carbonfibre body panels. A rear-mounted, 8.2-litre, supercharged V8 engine, burning a special blend of nitromethane fuel and producing close to 6000 bhp, supplies the power. To measure, and record, data in the ultra-harsh environment generated while this sort of power is being transmitted to the ground, Datron technicians fitted the company’s Microsat GPS-based Vehicle Performance measurement unit, plus 2D Data-logging system and sensors, to the dragster.
2D data logger with microSat and sensors were fitted, tested anc calibrated. The system is very compact and fits in unobtrusively
Aside from time, speed and distance, the data-logging system was set up to record additional inputs, including engine revs and rear axle speed (the difference is crucial in drag racing, as it indicates the amount of wheelspin being developed at any given point), fuel pressure, supercharger pressure and exhaust gas temperatures. In addition, the 2D logger was fitted with “x” and “y” accelerometers, which, as well as providing the acceleration profile of the car down the dragstrip, also showed the sideways forces being generated at certain times during the run by such phenomena as tyre shake (distortion) and chassis flex. It was also linked to an infra-red temperature sensor, mounted on the underside of the car, so the surface temperature of the track over the length of the quarter-mile could be recorded and correlated with the other data.
1. Engine RPM and 2.Clutch output RPM
1. Exhaust gas temp, 2. RPM, 4. Fuel pressure, 5. Axle RPM
1. Longitudinal Acceleration, 2. Lateral Acceleration, 3. RPM
On the day, the winning run by Wildside Inc driver, Darryl Bradford, saw him record an elapsed time of 5.543 secs and a maximum speed of 240.7 mph (an impressive performance, although two years later, Top Fuel times are now regularly into the 4.5-sec bracket, with maximum speeds in excess of 300 mph). Additional information recorded by the Datron system revealed a steep, linear acceleration trace to over 200 mph (that took just 3.5 secs), with car and driver being subjected to an almost constant force of 2.75 G for much of the quarter-mile, followed by similarly strong deceleration when the twin parachutes were “popped” and the rear-wheel disc brakes applied to slow the dragster.
Just by way of comparison, the performance figures recorded by the Wildside Inc car (0-60 mph in 1.03 secs, 0-100 mph in 1.72 secs and 0-150 mph in 2.53 secs) put a current-generation F1 car, also tested by Datron Technology, in the shade (0-60 mph in 2.58 secs, 0-100 mph in 3.87 secs and 0-150 mph in 5.78 secs). In fairness, the Top Fuel machine is rather more “focussed” than the F1 car, which has to be able to brake and go around corners at least as effectively as it accelerates in a straight line, which the dragster does not.
John Wright, owner of the Wildside Inc car, was clearly impressed by the Datron equipment after his experience at Shakespeare County Raceway, his comments also indicating that some of the data accumulated, but not made public (it might be of considerable interest to the team’s rivals), was leading him to re-examine some of his thinking regarding car design and set-up.
"As the (Datron) system was first developed for circuit racing, both bikes and cars, it has a larger memory, and therefore can log over a longer period of time compared with previous systems,” he observed. “It has seemingly endless capability to log all required data, some of which is the norm, but some of which is currently outside of the realm of other drag racing systems. The range of information retrieval possibilities available with the 2D Data-logging system has prompted me to question some of the accepted thinking within the realms of Top Fuel engineering.”
The interesting aspect to all of this is that John seems to be one of the enlightened few in his branch of the sport. Among Formula One, Sports Car, MotoGP and Superbike teams these days, where Datron and 2D are key suppliers, data acquisition and analysis is an integral and absolutely essential component of test sessions and race meetings. Strangely, however, this does not appear to be the case in drag racing, with only a limited number of competitors taking advantage of what is undoubtedly an invaluable race-engineering tool.
“It’s difficult to know why drag racing has been slow to accept the concept of data acquisition compared with other branches of the sport,” says Datron Technology General Manager, John Grist. “There is absolutely no question that it can assist both the engineers, in terms of understanding what their car is doing during a run and adjusting the set-up accordingly, and the driver, by allowing analysis of his/her performance during each run. In that respect, there may a bit of an attitude issue in some quarters of the drag racing fraternity, but the thing to remember is that correctly set up data-acquisition equipment provides a powerful tool for improvement. It is not, as some may imagine, a weapon to use against drivers or engineers.
Ever wondered why your spark plugs don't last a full race?
“There may also be a misconception among some in the sport that data-logging and analysis are too complex for them. The truth is, it’s not that complicated, and you don’t have to be an engineer to use it – or gain from it. For instance, if you watch motorcycle racers studying print-outs of their practice and qualifying laps, you quickly realise that is the case. They’re looking to see where they’re gaining and losing time on a lap, and they then work on adjusting their riding style for the next run in order to improve their performance. The same thing happens in other types of motorsport, where those using data-logging equipment can be seen to have a clear advantage over those who are not.
“In addition, depending on the vehicle parameters in which you are interested, data-logging can provide a highly useful diagnostic tool. It can assist with such critical areas as gearing – finding the right ratios to match an engine’s torque curve and keep gear changes to a minimum – as well as help to pinpoint problems with areas like damping, and in one case we encountered, wheel balance. Our experience is that once a team, or competitor, moves to data-logging and begins to understand what it can do, they just seem to go faster and faster.”
The other aspect that may be preventing drag racers from embracing data-logging is cost. Fortunately, many would say, the budget required to run a drag racing team, even in the upper echelons of the sport, is not at the same sort of level as Formula One or frontline sports car racing. Data-logging equipment may therefore be perceived in some drag racing quarters as an expensive “toy”, with budgets being better allocated to more obvious go-faster hardware.
“This is another fallacy,” counters John. “Our systems start at £1,500, although they can range up to £150,000, depending on client requirements. That said, we would nearly always recommend a competitor starts with a basic system, gets used to how it works, and then adds sensors to measure whatever additional parameters are felt to be most relevant to improving performance.
“In terms of drag racing, the essential information you require concerns wheel speed, engine speed and throttle position, although you can add further inputs, if necessary, such as exhaust gas temperatures, fuel pressure and tyre temperatures. Once you become familiar with the traces, you tend to stop scrutinising the details, unless there is something specific you’re watching for, and start looking for the trends and any anomalies that may be present. It’s that sort of information that can allow you to spot a developing problem with your car or pinpoint the cause of an existing one, and ultimately, could save you the cost of some serious engine damage, possibly even a blow-up. It has been estimated that, for a Top Fuel dragster, each run costs – conservatively – $1,000 per second. On that basis, you would have to say that a data-logging system looks like pretty good value for money.”
Data logging can be seen as cheap insurance if helps to prevent catastrophic engine failure
The latest news is that a front-running European Top Fuel team is in serious discussion with Datron Technology about using one of its systems this season, so perhaps the concept of data-logging is finally on the verge of gaining the sort of acceptance in the drag racing community that it enjoys in many other areas of motorsport. If so, it seems fair to expect even more mind-boggling elapsed times and maximum speeds to be laid down in the near future – which brings us neatly back to that basic correlation between speed, time and distance.
Story: Graham Jones