This story is the second in a series of articles on Detroit Speed and Engineering's new innovative QUADRA Link rear suspension system. For those of you who have seen Part 1, you'll recall that we are going to show you that great handling, performance, and ride can all exist simultaneously-something that the old timers said couldn't be done, and something that we are going to prove with the installation of a QUADRA Link. The plan was to take one of Detroit Speed's test and development musclecars and compare performance and handling characteristics before and after replacement of the old rear leaf suspension with their new QUADRA Link rear suspension system. We'll show through true direct comparison, after a carefully designed series of track tests, that we're not just blowing smoke. Let the testing begin.
For those who might have missed Part 1, here's a quick recap. The car we're using for the performance testing is a classic late '60s musclecar, the car that every baby boomer dreams of-a '69 Camaro SS (co-owner Stacy Tucker's beauty which she so willingly donated to this noble cause). For our comparison testing, we've equipped this beauty with a new 383 crate motor, Fikse 18x8.5 front / 18x9.5 rear wheels and Michelin Pilot Sport 245/40ZR18 front / 275/40ZR18 rear tires. In the first series of track tests, we'll pull down the performance numbers with the original rear leaf spring suspension installed. After completing the baseline testing, we will install DSE's QUADRA Link rear suspension system, and repeat the same tests with the same wheels and a new set of the same Michelin Pilot Sports for a true comparison.
The original game plan was to perform a quick, clean surgical strike by driving the Camaro over to a local Mooresville track, quickly set everything up, run our performance tests, and drive back to the shop. While at the track, we'd run a skidpad test to measure lateral acceleration (the number of g's reached before the end breaks loose), slalom and quarter-mile times-all true indicators of the car's performance and handling. We'd then return right back to the shop, install the QUADRA Link rear system, and return for the same series of performance tests. Easy stuff, right? Wrong!
As test time approached, the local track became unavailable. Normally this would not present a problem, but since this is a series of articles with a firm time commitment (that I so foolishly agreed to), we had to scramble. After about a half dozen phone calls, no luck in finding a track, and no confidence in our ability to find a suitable test facility, we finally found the test location that we needed. It was a little farther away than we wanted, but it turned out to be well worth the extra travel time. Thanks to the kind folks at the Laurinburg-Maxton Airport in Maxton, North Carolina, we could now get down to some serious business. The Maxton facility has a closed two-mile-long runway that dates back to World War II. This runway was used extensively up to and during the war to train glider pilots. It was certainly long enough, but there was a lingering doubt as to its condition. In the end, however, Laurinburg would prove to be a perfect location. The East Coast Timing Association (ECTA) uses this location each year for their speed trial events. On a warm, sunny North Carolina morning, we loaded the test Camaro into the trailer, pulled out of the parking lot, and headed to Maxton. It was a beautiful day; everything was going great and it only got better.
When we arrived at Maxton, we were greeted by airport management, given some guidelines to follow, and were then off on our own to run the SS through the tests. Our team quickly got down to business. To collect our performance data, we used a V-Box data logging system. DSE uses the V-Box system for all of the extensive testing and data acquisition that's done on its new products and systems. It's installed easily and logs data that can be downloaded to a laptop and then analyzed. The system we were using can measure the following parameters: acceleration times, braking distance, lap times, circuit position, and lateral and longitudinal forces.
The first set of tests with the original rear leaf spring suspension was designed to obtain slalom times through a 420-foot course. The course consists of six turns that are 70 feet apart, carefully measured out with cone placement. Two extra cones designate entry and exit from the course. The location of each cone is carefully marked, and if any cone is moved by contact, the run is automatically disqualified. If a cone is touched but it is not moved, then the run counts. The number of seconds it takes to pass through the slalom course is measured, and this time is then divided into the length of the course giving a foot-per-second (fps) measurement. This measurement is then translated into miles-per-hour (i.e. when you are driving 60 miles-per-hour you are traveling at 88 fps). As the car weaves through the course, the slalom gives important information about the car's handling; the quicker you can navigate the course, the better your road-hugging ability. Multiple runs were made, and the Camaro pulled down times as you would expect this high-powered vintage musclecar to do, while exhibiting a fair amount of body roll, which should be cured by the Quadra Link installation.
The Slalom Numbers-Baseline
|Slalom Pass||Speed (mph)|
Our next order of business was the skidpad test. (Please don't try this at your nearest neighborhood intersection). We measured off the correct distance to create a 125-foot-diameter circle and set out the cones for our test. This test is really pretty simple: you run the car in a big circle around the outside of the cones as fast as you can until you can't hold it anymore, and when it finally breaks loose, the V-Box records the g-force number you were at. The time that it takes for our Camaro to travel around the outside of the cones has a direct relationship to its grip or road-holding ability. The better the grip, the faster you can go. All the runs went clean and we logged some pretty impressive numbers, but as I watched the car run I could actually see by the excessive body roll that the times would be a lot better with a modern high-tech suspension. Maybe these guys are onto something. After downloading the data and running it through analysis, we came up with 0.81 g's as our breakaway number.
The final testing obtained some run times for the standing quarter-mile, and our Camaro ran the quarter with decent speed, although the e.t. was not that great considering the amount of wheelspin we had at the start. Our average elapsed time was 15.16 seconds at a speed of 98.62 mph. This is understandable with the stock rear leaf springs still in the car, but since Detroit Speed claims that the QUADRA Link will transfer energy from the drivetrain to the pavement more efficiently and also eliminate wheel hop, we would expect to see significantly lower quarter-mile times once the leaf spring suspension is replaced. Remember, the only change that will be made is the installation of the QUADRA Link. Tires and wheels remain the same, giving us a true A/B comparison test.
With testing completed for the day (and those beautiful Michelins ground up like I expected), we loaded the Camaro into the trailer and headed back to Mooresville. When we return next month, we'll document the installation in detail and present the data from the Part 2 tests. The numbers will tell the story.