asphalt circle track leaf spring setup

Although they are the oldest, they seem to be the least understood. We always start with the front end geometry on any race car. A trend must prove itself in order to stand the test of time. If a manufacturer decides to produce a spring utilizing chrome silicon (.625) wire in lieu of a .710 where the stress levels are too high, then the spring will more than likely loose free height, take set and even in some cases break. The setup we choose needs to be arranged so that the dynamics are balanced between the front and the rear suspensions. All of theGOLD COILSare packaged with dyno sheets detailing the dynamic rate in a graphical form as well as numerical form. Leaf springs are the oldest form of suspension in racing. What is important is how each tire is toed in or out in relationship to to the center line ofthe car.You can lead or trail the rear axle to get there but,setting the toe in the rearend housing first worked better for me.If the housing has 1/8 toe out heat the front of the tubes till red then throw cold wet rags on them.This will bend the tubes slightly if you go over 1/8 it could cause bearing trouble. So, here is, in order of logic and importance, a list of setup parameters we need to address to make our cars fast and consistent. Try to install shock rates to complement the car's setup. We race a '76 Pontiac LeMans with the 4 link rear. Conclusion Good luck. The farther left the MC is located, the more efficient the front end will be and will want to roll. You may not be able to find a 16-inch 100 rate spring, so this provides more spring length to use. The shape of the racetrack can affect how the car is balanced when exiting the turns. The length decreases, the width increases, the thickness increases, the number of leaves increases, Brinell hardness increases, utilizing a harder durometer bushing. We run a monoleaf on the right and a stacked leaf on the left. In testing conventional setups over a five-year period, it was discovered that most tires want no change in camber relative to the racetrack surface as the car dives and rolls. With excess Ackermann designed into our cars, on purpose or not, we can gain a lot of toe-out, which causes our front tires to work against each other. Free of . The stiff LF spring setup does not work well on tracks banked over 10 degrees. The number one reason a car will be tight and not want to turn is because the front end is not designed properly. Both of these are necessary components that will be needed to win championships. Balance is spoken of in all types of motorsports these days, even F1. Only use springs manufactured by companies such as LANDRUM SPRING that have a complete manufacturing facility. We can also use prodive to hasten the movement of the left-front corner on turn entry. Afcos web site has leaf spring installation tips.I ran camaros and what I did was raise the front eye 3/4 and lower the rear 3/4''.A flatter spring has less rear steer and should have more anti squat.2'' lowering blocks is the most I ran,make some heavy duty ones yourself .I broke several that I bought.Check the toe out in the rear end houseing, heat and quench the tubes to get 1/8 toe in.Then string the car to get the r/r toed in. Decrease the Pre-Load on the Front Stabilizer Bar. Just giving the car more rear traction, period, does not help us if the car becomes too tight in the middle of the turns and we could end up with the reverse of what we need. For example, if the spring is beveled on the flat end instead of ground flat then the spring is not coming in true contact with the jack bolt plate. It helps to install brake bias gauges and then adjust the amount of pressure front to rear. When should one use high or low arched springs? HOW TO EXAMINE AND CHOOSE YOUR HIGH PERFORMANCE LEAF SPRING. There can be a small amount of rear steer as the. Furthermore, the life of the spring will be extended due to the fact it is not under high stress, but more importantly, handling will be consistent. One should use the same free height, but change rates. Coil springs are the most common used spring in most all motor-sports today. Then all you have to do is maintain that balance throughout the season and that means resisting making changes that take you outside that envelope. Theinboard mounting positionof the springs play an important role as well. Landrum Performance Springs offers a range of aftermarket suspension springs used primarily in Circle Track Racing, Drag Racing, Off-Road Racing & Powersports markets. No one including us can guarantee every spring to rate out exactly. A front wheel offset to the outside will increase leverage of the lower A-frame against the coil spring, and the nose of the car will be lower. Ackermann is easily checked by using a laser system or strings. The following spring/shock combinations are recommendations only. The amount of difference you need is directly influenced by the installed motion ratio of the spring and the spring rate. For example, when the leaf springs are toed in (the front eye locations closer together than the rear mounts) the lateral rate or twisting resistance is increased, therefore ones side bite rate is increased. This can cause an undesirable change in spring rate and wheel base settings. Maximum U-bolt torque for 1/2 diameter, plated U-bolts are 45 lbs. The reason I say that with confidence, is because I have gone up against more aero efficient cars with setups and body configurations that were aero-deficient and still out ran them. Furthermore, the crew made unnecessary changes, wasted valuable time, resulting in wear and tear on the engine, tires and other components. endstream endobj 209 0 obj <. The following information applicable for most oval track Chrysler styles mono and multi-leaf leaf spring applications with the sliders mounted on the rear. CTS SUPER DUTY LEAF SPRING ROLLER STYLE SLIDER-CHEVY OR CHRYSLER STYLE. Changing spring rates is a primary setup tool to get both ends of the car to match up their attitudes. Softer grades tend to stretch under stress created while tightening instead of maintaining compression between the spring and axle perch. The LF static camber must be increased quite a bit, and the RF static camber must be decreased. Decrease Upper Control Arm Angle on the Rearend. Some teams refuse to run sufficient stagger to match the radius and banking of the racetrack. The completely closed-ends are used when the requirement is that rate remains more consistent throughout the coil springs travel. Those were salvaged out of the old car and were perfectly fine. No matter which stiffness you decide to go with, the most important aspect of setup is balance, and you achieve that balance with the correct combination of springs, moment centers, sway bars, and load distribution. 241 0 obj <>stream This develops more crossweight as the car squats on acceleration. by RCJ Wed Jun 22, 2011 9:05 am, Post When this is severe, the front end will push and no adjustment to other setup parameters will seem to help the situation. To increase resistance on the left rear, one may incorporate a 225 lb. Stiffening the LF and/or softening the RF spring decreases dynamic wedge during deceleration. Also, by increasing the lowering block height, one will be raising the axle height or lowering the front eye which will increase chassis roll. Since the spring promotes rebound and resists compression as inherent properties, then the shock rate of compression control must be less than the rate of rebound control. Simply grinding the spring flat after forging it is like putting excessive ketchup on a bad hamburger. One of the very first tasks in setting up a race car is to make sure all of the alignment issues have been corrected. At the end of the day, the springs where rated. Free rateis the rate of the spring when it is out of the chassis. We can reduce the rear spring split if we are using a softer right-rear (RR) spring by stiffening the RR spring and/or reducing the LR spring rate. It's been three years since we discussed the subject of handling fixes. Every race car needs a certain amount of tire stagger. If the front geometry is not designed correctly, then as the car dives and rolls, the RF camber relative to the racing surface will change and the tire will lose grip. If I have a split rate shock such as 3-5 and I turn the shock 180 degrees, will the shock then be a 5-3? Even though the winding process using CNC automated equipment is consistent, the variances in the quality of spring wire is not as consistent. Allstar Neck . If we have a top view difference in alignment between the transmission output shaft and the pinion shaft and they are parallel, then the angle to the driveshaft created by that misalignment might be sufficient to provide the needed angular differential needed for loading the U-joint bearings and reducing negative harmonics. A very good set of adjustable shocks came with the car also and that helped us when it came time to do the setup. If too much of the bias is on the rear brakes, the car will be loose under heavier braking. "There are two or three basic setups which are really simple, compared to bar car setups. The left side suspension usually is designed with about half the angle of the right side in a conventional design. Reduce the crossweight in a tight car and increase the crossweight percentage in a loose car. When the car is jacked up during a pit stop for a tire change, the suspension may become completely unloaded leaving the coil spring to rotate in the spring bucket. Whenever a manufacture sets up to run several hundred springs of one particular rate, the end result is less than perfect. Meaning that as the spring is compressing it is gaining rate. Either of these two can be caused by an unbalanced setup or by running with the wrong amount of crossweight. In addition, banding clips are frail and tend to break under impact or stress. Clipshave a profound effect on spring rates. This is the true arch of the spring. With the LF A-arm being shorter than the LF lower control arm your car will lose camber under the left front suspension compression created by the big bar soft spring set up. Most companies incorporate a metal tag denoting the theoretical rate of each spring. The disadvantage is that they produce inconsistent spring rates. can develop a winning setup. In addition, as the spring is put under load the shackle angle increases; therefore, the spring rate decreases under travel. by RCJ Mon Jun 20, 2011 9:28 pm, Post Leaf springs perform the following tasks: Due to all the loads leaf springs are under, it is one of the most stressed components on the race car. We have been softening those setups over the years, but never intended to go to coil bind or bump rubbers. And as for you Modified and Stocker class teams, don't even think about it. LIT-719 80292 C7 Corvette Radiator. When the front bushing is allowing the front leaf spring to pivot, it transfers all the side loads and lateral forces to rear portion of the leaf spring and shackles or sliders, which were not designed to handle the additional stress. It is possible to have Ackermann in our steering system when we steer left and reverse Ackermann when we steer to the right. With this system you can run a softer rate on the top and a stronger rate on the bottom. The track radius used to determine stagger matters the most where the car will be accelerating. Furthermore, if in the event that there is a spring failure, we can trace the springs history and make up all the way back to the wire source. In the front-end geometry, there is a condition called Ackermann. After the supposed spring change, the team then began to change shocks, sway-bars, and pan-hard bar heights. We were 0.13 faster than we qualified. Designed for drag racing where maximum weight transfer is needed. On a metric four-link car, the four control arms determine the rear moment center height too. These data sheets clearly shows the details of the load in pounds of force, in increments of 1/10th of an inch for each and everyGOLD COIL. On asphalt, don't make large changes to components that .