Crunchin' the Numbers

The ABCs of High-Performance Testing

Andrew Schear Nov 13, 2003 0 Comment(s)

It's funny, everyone says they've got a 12-second streetcar. I myself have found more entertainment than truth in this statement. The fact of the matter is simple, many backyard hot rodders have never been to the track with their machines, and those who have know what it takes to run a 12.0 on street tires. The same rule applies to gear heads who install every aftermarket suspension component known to man on their '65 whatever in hopes that it'll handle like Jeff Gordon's Nascar. The reality is basic, some parts work and some parts don't, and too many of the wrong parts cause a lousy ride and negative performance. The only real way to see if a given mechanical upgrade is worth its beans is quantitative testing. Now don't get us wrong, the feeling that one derives from the seat of their pants is valuable, but it's hard to validate. What one person considers a smooth ride, another considers a 4x4. For this reason we've decided to break down the numbers, and show you how well aftermarket drivetrain and suspension components work while under the strict scrutiny of timing machines, radar guns, and the like.

Before we go any further we'd like to point out that all the testing done here at SUPER CHEVY is done on a closed course with safety as the number one priority. The main difference between what we do and what the other guys do is we do it with 30-year-old musclecars. That being said, we'd like to get to the technology that makes it possible to be accurate. Our mornings begin with the set up of our Stalker ATS radar system. The ATS system is responsible for gathering 0-30 mph, 0-60 mph, quarter-mile times, eighth-mile times, 60-0 braking distances, and any other straight-line factor we deem necessary. All the acquired information from each pass is saved in a PC laptop and edited on site. In order to keep our testing accurate, we correct every acceleration pass to a "Standard Day" correction, which is 60 degrees F with zero percent humidity and 29.92 inches of mercury. How do we do this? Simple, we employ the algorithms of Computech Systems who manufacture the RaceAir Pro weather analyzer. The RaceAir is an all inclusive weather machine that calculates a correction factor based on temperature, relative humidity, and barometric pressure. All one needs to do is press the sample data button and enter a given e.t. and mph and the RaceAir outputs the standard day correction. Wham, accuracy is achieved.

Just as radar is used for straight-line acceleration, timing systems are used for lateral acceleration and slalom testing. In the name of simplicity, we will define speed as a relationship between time and distance, as such, all of our g-measurements and slalom measurements are acquired with a wireless Brower Timing System. Our 420-foot slalom uses one invisible beam at each end of the course. When the car triggers the first beam, a wireless signal is sent to a hand held receiver. When the car passes through the second beam, the timer stops. As plain as this system seems, it works more accurately than any other system in existence. Once the number of seconds it takes to pass through the slalom course is acquired, it is divided by the length of the course, thus giving us a feet-per-second (fps) measurement. We can then translate the number of fps to an actual mph.

Using the same Brower technology, we measure off a 100-foot radius to create our 200-foot skidpad. The time it takes for a vehicle to travel around the circumference of a 200-foot diameter skidpad has a direct relationship to its roadholding ability. For example, if a vehicle weighing 2,000 pounds can pull 1 g on a 200-foot skidpad, its lateral roadholding ability is equal to its weight of 2,000 pounds. This means that a given vehicle that pulls 1 g can actually hold its own weight while in a turn, solely on grip.

We've learned that performance testing is a great way to measure how well a given aftermarket system works. Yes, it can be said that many mechanical parts have a cosmetic value, but do they work? Keep your eyes peeled for SUPER CHEVY Road Rage tests, we'll let you know what works and what doesn't. See y'all at the track!

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The Stalker ATS is similar to law enforcement systems. The main difference is the ability to download data to a personal computer.

After saving our raw radar data, we use our Computech RaceAir Pro to correct each spec to a "Standard Day" correction. In addition to e.t.'s and 0-60s, our RaceAir is capable of horsepower correction factors as well as other engine formulas used by professional race teams.

Our Brower Timing system has a practical range of almost a half mile. Using two sets of invisible beams we have the ability to precisely measure the time it takes to travel any given distance.

Our 420-foot slalom consists of six turns 70-feet apart. Two extra cones designate the entry and exit of the slalom. If any cone is moved from its painted box, the run is automatically disqualified. If a cone is touched but not moved, the run counts. While the run is measured in seconds, the end result is measured in mph. (Illustration by Brenna Stoffers)

The skidpad is measured as an average of clockwise and counter-clockwise circles. The driver makes sure to align the driver's side tire with the dotted line of the path going both directions. Since clockwise represents a slightly smaller circumference and counter-clockwise represents a slightly larger circumference, the combination is an accurate average. (Illustration by Brenna Stoffers)

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