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Drag Suspension Test - Forward ProgressA deep study in improving a New Edge ’Stang’s straight-line performance From the June, 2011 issue of 5.0 Mustang & Super Fords
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Horse Sense: Thanks to heads-up drag racing, such as the Pacific Street Car Association and West Coast Hot Rod Association, each year we’re able to conduct drag tests with our SoCal-based project Mustangs on several well-prepped West Coast tracks (Auto Club Speedways in Fontana and Bakersfield, California, and at The Strip in Las Vegas). This July 8-10, the NMRA (along with its NMCA brother) returns to the West Coast after a 9-year absence for the NMRA/NMCA West Coast Shootout at Fontana. We know many Western-based ’Stangbangers have hoped for something like this for many years. Well, your wish is finally being granted. Corner-weight measurements... Corner-weight measurements were taken before our ’02 Mustang GT was tested at the dragstrip in street/road-race and street/’strip trim. Adjusting the corner weights is done by placing the car on four perfectly level scales, then adjusting the car’s height at each corner. To add weight at a given corner, the spring at that corner is raised and its opposing spring lowered (by adjusting spring perches). The scales showed us that control arms, shocks, springs, struts, wheels, and tires designed for hugging curves are much heavier than their drag-race counterparts. Our ’Stang’s poundage (with driver) went from 3,827 at Fontana to 3,723 when the lighter wheels and tires were installed for testing in Las Vegas. If you’re a veteran reader of 5.0 Mustang & Super Fords, you probably noticed long ago that we try to provide as many critical details as possible in all of our reports about Mustang parts and new technology. Seriouslyour tech editor and Associate Editor Mike Johnson honestly believe that details, good or bad, have to be near the top of Editor Steve Turner’s favorite-things-in-life list. This is so engrained that your tech editor goes to sleep with Steve’s don’t leave a shop without getting all the data mantra running through his mind. Yes, the boss is a stickler for details, but we certainly don’t fault him for that endearing quality. This latest experiment with our project ’02 Mustang GT was an exercise in the type of detailed data collection we typically don’t have the opportunity to pursue. It involved several days in the shop and at the track (including some eleventh-hour parts breakage and overnight-rush shipments), which usually are impossible to smoothly synch with a magazine’s production schedule. For this effort, your tech editor, along with Chuck Schwynoch, Jack Hidley, and Luka Dugandzic of Maximum Motorsports, thought it would be interesting to take a closer, more-scientific-than-usual look at a ’99-’04 Mustang’s dragstrip launch. We wanted to examine how critical suspension components and weight-reduction are to street/strip ’Stangs. In most tests like this, front and rear suspension parts are bolted on, and changes in a Pony’s 60-foot and other incremental times throughout the quarter-mile are used for validating or rebuking the parts’ effectiveness. While this data is fine from a general standpoint, there’s a lot more behind the way ’Stangs react when the clutch or transbrake are released. One thing that’s widely overlooked is the fact that control arms, shocks, struts, wheels, and tires not only have to work together during the hard-acceleration segments of a Mustang’s life, they also have to collaborate with the surface of the street or race track. Maximum Motorsports’ engineering... Maximum Motorsports’ engineering manager, Luka Dugandzic, connects the GPS antenna to the Motec datalogger attached to the rollbar in our project Pony. The GPS enables the datalogger to record absolute time and date, as well as the Mustang’s speed, exact position, direction of travel, latitude, longitude, and altitude. Note that we also collected in-car video footage of each test pass using a Chase Cam PDR-100 video recording system. Over the course of two PSCA race events in late 2010, KJ and the engineering braintrust at Maximum Motorsports joined forces to evaluate the way our ’02 test-mule leaves the line. We started in street/road-race trim, outfitted with Maximum’s full suite of grip-for-twists-and-turns hardware, heavy 17-inch FR500 wheels, and Nitto NT05 tires. Then we transformed it into a street/strip persona, featuring the company’s new developmental drag-race pieces and some trick, lightweight running gear from Race Star Industries. Using chassis scales to measure weight and a Motec ADL3 datalogger to record hard-core statistics for each run, we were able to learn exactly what the ’Stang’s various movements and speeds are from the moment the clutch is released. Of course, we also had the objective of getting our Mustang to cover 1,320 feet as quickly and consistently as possible. While we confess there were difficulties with that effort, we’re quite pleased with the improvements that resulted from changes that were made, as the data shows our ’Stang’s elapsed time would have been greatly improved over its baseline numbers. The accompanying photos, data graphs, and captions offer a small synopsis of our research, and are an example of how important data collection is to companies such as Maximum Motorsports, as it’s real-world experience and information that helps them produce parts that many of you consider for making your Mustangs better.  Tech s pecialist Jack Hidley...  Tech s pecialist Jack Hidley plugs the datalogger harness into the connector for our ’Stang’s passenger-side (rear) wheel-speed sensor. The connector is located below the rear seat cushion.  Tension and compression loads...  Tension and compression loads imposed on a Mustang’s rear lower control arms (at launch) are among the criteria we’re measuring in our study. To capture data, a strain gauge is attached to the rod end of Maximum’s tubular lower control arm (PN MMRLCA-51) and plugged into the Motec.  Unfortunately, we did not...  Unfortunately, we did not have photo support during our baseline tests at Auto Club Dragway. However, you can be sure that our Mustang’s launches and 60-footers were far from anything that could be considered exciting, save for violent wheelhop that took its toll on the driver-side axle. We made five hits with the street/road-race suspension setup, and back-to-back 2.12 (60-foot), 12.88 e.t., and 113/111 mph proved to be the consistent bests of the day. Note that a 2.08 60-footer was recorded on the first pass, which was aborted after wheelhop came on beyond that point.  With our baseline tests completed,...  With our baseline tests completed, our GT’s suspension makeover was left in the capable hands of Source Interlink Media’s Grant Peterson, the lead wrench at the company’s all-new whiz-bang Tech Center. Ride-height measurements (26.75-inch front and rear) were taken before any parts were removed, to ensure the ’Stang sits the same way when we begin Phase 2 of the experiment at The Strip at Las Vegas Motor Speedway.  For the front, a set of Tokico...  For the front, a set of Tokico Illumina drag struts (PN RB3140) and Hypercoil 14x2.5-inch, 200-in/lb springs were installed with Maximum Motorsports’ coilover kit (PN MMCO-2). The struts feature five adjustments, with settings for snappy reaction and weight transfer on the track, and firmness for manageable street/freeway driving.  The ’02’s rear suspension...  The ’02’s rear suspension is being transformed for the strip with Tokico D-Spec adjustable shocks (PN DE3723); H&R Super Race rear springs; and Maximum Motorsports’ Extreme Duty adjustable, rear lower control arms (PN MMRLCA-33).  After taking measurements,...  After taking measurements, Grant raises the ’Stang on the Tech Center’s twin-post hoist, removes the front wheels, and then extracts the Maximum Motorsports struts and coilovers.  Here is a comparative look...  Here is a comparative look at Maximum’s Sport Series front strut (left) and the Tokico drag strut (right). Notice the difference in thickness? The road-race strut is larger due to its inverted-piston, monotube design (the fluid is in the upper, polished portion), which provides lower unsprung weight for improved handling. The piston-housing’s large diameter and bushings that separate the strut’s inner and outer tubes reduce friction, and greatly improve the strut’s resistance to bending during cornering. By contrast, the Tokico strut is a twin-tube design, having two concentric tubes that are separated by oil (the piston is mounted to the hollow strut shaft, which comes down from the top).  These photos illustrate the...  These photos illustrate the 4-inch height difference between the new Hypercoil spring (left) and the 10-inch Hypercoil 350-in/lb spring it’s replacing.  Installing softer (200-in/lb)...  Installing softer (200-in/lb) front springs reduces the front suspension’s roll stiffness, which improves traction and forward motion when launching.  Here is a closer look at the...  Here is a closer look at the coilover rear suspension that was used for the Mojave Mile event. Mounting the springs directly to the back of the axle (as coilovers) gives the springs maximum leverage against the ’Stang’s movements (eliminates compression from body roll, reaction to bumps, and so on), which results in a stiff suspension and hard ride.  By contrast, with Maximum’s...  By contrast, with Maximum’s adjustable rear lower control arms (MMLCA-33) and H&R Super Race springs installed, the springs’ new mounting location (on the LCA and forward of the axle tubes), gives the rear end more leverage against the spring. This change in rear-suspension geometry results in a softer setup for a given spring stiffness.  Notice the marked difference...  Notice the marked difference between the drag-race control arm (top) and the non-adjustable LCA (PN MMRLCA-31.3). The adjustable arms facilitate making ride-height and corner-weight changes, which are critical for achieving good launches.  Maximum Motorsports’ rear...  Maximum Motorsports’ rear sway bar (PN MMRSB-7) features a 1x0.120-inch-wall tube, and adjustment settings that allow us to dial-in the Mustang’s roll stiffness and overall balance based on horsepower and available traction/track conditions.  A minor rearend repair was...  A minor rearend repair was necessary before installing the sway bar. Props go out to JC Cascio of Strange Engineering, Jeremy Martorella at UPR Products, and UPS’ Next-Day-Air service for getting us a replacement 31-spline axle and a billet diff cover in record time.  While the adjustable sway...  While the adjustable sway bar is a 100-percent bolt-on part, Grant sparked the Tech Center’s Lincoln Electric 140c power MIG welder and attached the bar’s brackets to our project ’Stang’s frame.  Here’s the ’02 GT’s revamped...  Here’s the ’02 GT’s revamped rear suspension. The Maximum Motorsports race torque arm (PN MMTA-5) is a holdover from the original chassis upgrades. The arm controls the rear axle assembly, preventing it from rotating under hard acceleration or braking.  After a long day of installation,...  After a long day of installation, we calibrated the ’Stang new suspension at 27 inches in the rear and 26 inches up front. The second round of testing will begin with street wheels and tires in place, with a switch to lighter, drag-race running gear once launch data is recorded. In most cases, e.t. and speed are the primary focus when we perform tests taking Mustangs from Points A to B on the dragstrip. However, for this project, we decided to put those two criteria on the back burner and center our research on collecting quantitative data (using a Motec ADL3 datalogger) to see the differences in our Mustang’s launch characteristics when the car is outfitted with street/road-race suspension gear and street/strip hardware. Maximum Motorsport’s owner, Chuck Schwynoch, and his team (Engineering Manager Luka Dugandzic and Tech Specialist Jack Hidley) have been most helpful when it comes to recording data and tuning a ’Stang’s suspension based on that info. Team Maximum provided outstanding trackside assistance for our entry in the 2010 Castrol Syntec Top Car Challenge. Their collective knowledge and suspension calls helped us secure a Fourth Place finish in the competition. After outfitting our ’Stang with the datalogger and making runs over the course of two test sessions, the data (results) showed us areas of inefficiency when stiff, road-race-specific components were on the car, and how the same launch variables improved when changes were made. The important thing we learned from this project is that setup is critical to various Mustang-performance applications. Simply bolting suspension parts on your Pony is one thing. However, when parts are designed for a specific use, their optimum performance will only come through testing and collection/analysis of data (using timeslips or a datalogger).  Maximum Motorsports’ owner,...  Maximum Motorsports’ owner, Chuck Schwynoch plugs the Motec ADL3 data-logger harness into the ’Stang’s factory wheel-speed sensor connector on the driver side. The logger measures acceleration in the fore/aft, left/right and up/down directions.  Our baseline tests at Fontana...  Our baseline tests at Fontana were made with the Pony’s suspension still in its Mojave Mile configuration (set up with corner weights being equal all around, for optimum handling and stability). In Las Vegas, Chuck decided to raise ride height approximately 2.5 inches. Increasing height raises the center of gravity, which increases weight transfer for a given acceleration. Increasing weight transfer to the rear tires promotes good traction and thus generates harder, quicker acceleration. Secondarily, raising the rear of the car also limits the amount of rebound from the tires, and ultimately keeps them from spinning. A ½-inch-drive ratchet is all that’s needed to make jack-screw adjustments on Maximum’s drag-race lower control arms.  End-links for the adjustable...  End-links for the adjustable rear sway bar and Panhard bar were equipped with strain gauges affixed to their rod ends. The strain gauges allow the ADL3 to record the tension and compression loads on each bar, giving us valuable information about the Mustang’s body roll at launch. We ultimately want the body roll to be fairly low, less than 1 degree. This type of data will give us a guideline on how to adjust the ride height to optimize roll angle. End-links for the adjustable... End-links for the adjustable rear sway bar and Panhard bar were equipped with strain gauges affixed to their rod ends.  The strain gauges allow the...  The strain gauges allow the ADL3 to record the tension and compression loads on each bar, giving us valuable information about the Mustang’s body roll at launch. We ultimately want the body roll to be fairly low, less than 1 degree. This type of data will give us a guideline on how to adjust the ride height to optimize roll angle.  Wheels and tires became one...  Wheels and tires became one of our big concerns with this project. We knew that the rears would be downsized to 15s, but there isn’t a 15-inch front-runner on the planet that will clear the big six-piston Wilwood binders on our Pony’s front end. Race Star Industries’ 92 Drag Star front wheels (17x4.5-inch, available through Latemodel Restoration Supply) make brake-caliper clearance a non-issue. When paired with M&H Tires’ Racemaster 26x4.5x17-inch front-runner/skinny front tires (DOT certified, available through Summit Racing Equipment), all the bases are neatly covered.  We completed the Mustang’s...  We completed the Mustang’s wheels package with 15x10-inch 92 Drag Stars for the back. The rear wheels’ 6.5-inch backspace allows perfect fitment of Mickey Thompson’s ever-popular 28x10.5-inch drag slicks on ’99-’04 Mustangs with stock-length rearends.  For hard-core competition,...  For hard-core competition, installing Maximum’s new drag-race rear sway bar (1.25x.025-inch) provides more than 2.5 times the stiffness of the street piece.  For hard-core competition,...  For hard-core competition, installing Maximum’s new drag-race rear sway bar (1.25x.025-inch) provides more than 2.5 times the stiffness of the street piece.  In street/road-race trim,...  In street/road-race trim, our project ’Stang leaves the starting line without any weight transfer to speak of, which results in spinning and/or hopping rear tires. Notice how wide the separation between tire and body is at the back of the car.  This is the data log from...  This is the data log from our first pass with the race-suspension pieces installed, and the 17-inch wheels and tires. The key data points are engine speed (rpm: red trace), acceleration rate (Gs: orange trace), wheel speed (mph: pink and light blue traces) and throttle position (green trace). What’s interesting to note is that while we still experienced some tire spin and then severe engine bog with this setup, the ’Stang still pulls 1.4 Gs on this launch—our best during this initial test session. (See datalog enlargement at 50mustangandfastfords.com.)  When using slicks and Maximum...  When using slicks and Maximum Motorsports’ drag-race suspension pieces, the Pony’s initial torque severely wrinkles the sidewalls, and actually lifts the right rear tire and pushes down harder on the left slick. To compensate for this, we adjusted the corner weights to put about 250-in/lb more weight on the right rear, ensuring that when KJ dumps the clutch, there is equal weight on both rear tires, which gives the most forward traction possible. As the car accelerates and weight transfers from front-to-rear, the front end extends (bringing the tires about two feet off the ground) as our ’Stang gallops forward and the slicks start to return to their original shape due to centrifugal forces and reduced engine torque.  When using slicks and Maximum...  When using slicks and Maximum Motorsports’ drag-race suspension pieces, the Pony’s initial torque severely wrinkles the sidewalls, and actually lifts the right rear tire and pushes down harder on the left slick. To compensate for this, we adjusted the corner weights to put about 250-in/lb more weight on the right rear, ensuring that when KJ dumps the clutch, there is equal weight on both rear tires, which gives the most forward traction possible. As the car accelerates and weight transfers from front-to-rear, the front end extends (bringing the tires about two feet off the ground) as our ’Stang gallops forward and the slicks start to return to their original shape due to centrifugal forces and reduced engine torque.  When using slicks and Maximum...  When using slicks and Maximum Motorsports’ drag-race suspension pieces, the Pony’s initial torque severely wrinkles the sidewalls, and actually lifts the right rear tire and pushes down harder on the left slick. To compensate for this, we adjusted the corner weights to put about 250-in/lb more weight on the right rear, ensuring that when KJ dumps the clutch, there is equal weight on both rear tires, which gives the most forward traction possible. As the car accelerates and weight transfers from front-to-rear, the front end extends (bringing the tires about two feet off the ground) as our ’Stang gallops forward and the slicks start to return to their original shape due to centrifugal forces and reduced engine torque. Here’s the data log from the ‘Stang’s hook-and-book launch with Maximum’s drag-race suspension, and lightweight wheels and tires on board. Notice how despite this also being a (peak) 1.4-Gs launch, all of the traces start much quicker and are more aggressive than those in our street-trim graph? Th  When it comes to making a...  When it comes to making a complete and totally clean pass down the dragstrip, the dark cloud of parts breakage continues to hang over our heads. After discovering axle damage and thrashing to get our test ’Stang ready for testing in Las Vegas, we proceeded to destroy this 4.30 ring-and-pinion set during our first pass in Sin City with Maximum’s drag-race pieces installed. Thanks to great assistance from fellow racers and a local driveline shop, our Pony returned to action with a set of 3.73s. Of course, the gear change brought about a huge change in the car’s launch/60-foot potential and overall quarter-mile performance, so our focus in this effort is to examine what’s happening (data wise) at the release of the clutch. 5.0
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