Increase the Rear Brake Bias. And as for you Modified and Stocker class teams, don't even think about it. At the end of the day, the springs where rated. Leaf springs possess many desirable suspension features, such as dampening, forward bite, roll over steer, high anti-squat percentage, and high lateral stiffness. Manufactured from only the best high-tensile chrome silicon material. The tire temperatures still supported his feel. They report running about 0.75 inch and complain that the car is tight off the corners. ASPHALT MODIFIED (Standard 3 Point and 4-Link Cars) 2006 Set-Up and Technical Guide. Our extensive testing has proven this component to produce very erratic handling characteristics. Proper U-bolt selection is critical, use only Grade 5 U-Bolts. The setup is balanced when the LF and LR tire temps are similar. Furthermore, there will tend to be less stress on the spring and spring related because the pressure will be equally distributed throughout the spring and chassis. In that time, a lot has changed with how racers on asphalt set up their cars. Good handling has often been thought of as a car that is neutral as it runs through the entry, middle, and exit phases of the corner. The very first step in the process of preparing for the new season is to consider all performance-related items and how they worked last season. Considering 4-link systems dominate the late-model market and even some classics, let's start there. Low-banked tracks require a location more to the left and higher banked tracks are best set up with a MC more to the right of centerline. When towing the race car, avoid strapping the vehicle by the chassis. Doing this will probably make the car loose off the turns while under power. Whether you're looking to drop your car for better handling and an enhanced look, or lift your truck so you can climb over rocks and trees and add that aggressive look, we've got you covered! Therefore, decreasing its long term effectiveness and life. Remember that drag is an important aspect of aero design. Although they are the oldest, they seem to be the least understood. Changing spring rates is a primary setup tool to get both ends of the car to match up their attitudes. Try to understand how aero downforce is created and then configure your car so that you take advantage of every area where you could produce more downforce. Published: Mar. An unbalanced car can be very fast, although the thrill lasts but for a short time. Same weight, same board, but now let's use a 25 pound spring and a 50 pound spring. For example, while testing at Charlotte, a car had a 375# tagged spring in the rear, the driver felt that the car was loose on corner entry and the Hoosier tire temperatures supported his feel. This develops more crossweight as the car squats on acceleration. by RCJ Mon Jun 20, 2011 9:28 pm, Post with r/r toe out the r/r wants to go to the wall you have to back steer and this makes it harder to get under a car coming off the corner.You always want to check the rear axle alignment because if you crash and have to put a new axle under it and the new one is toed different you could waste 2 or 3 weeks getting the car back right.I've checked a lot of housing,the winters quickchanges are good out of the box ,but the junkyard and 5 on 5 floaters are all over the place .I have found over years of racing that if my r/r has 1/16 to 1/8 toe in and the car is still loose I need to look at the springs,weight shocks etc.. LIT-721 80293NDP 2009-2015 Cadillac CTS-V HE. If one corner of the car is shocked stiff, then as that corner desires to move in compression, more load will be retained by that corner as well as the opposite diagonal corner of the car during the compression cycle only. I'm not saying this is not important to some degree, but on short tracks I would stress that aero downforce is over-rated in most cases. FYI, the springs shown here are stock ride height for a 1970 Nova. right rear leaf spring with matching arches. Good luck. A very good set of adjustable shocks came with the car also and that helped us when it came time to do the setup. (See Figure below.). Free of . Squared end leaves produce high stress points in each leaf leading to premature failure of the leaf. This malady is more common than most racers know. The rear tire sizes must be different in order to compensate for the turn radius so that the rpm in both rear wheels will be equal. The cure must address where the car is not handling and ideally not affect those areas where the car is good. Decrease the Split on the Rear Panhard Bar Heights. If the wheel is turned farther at speed, the car is tight. With the exception of U-Bolts LANDRUM recommends Permatex Anti-Seize on all leaf spring bolts, pivoting points, and slider components to promote free movement in the suspension. 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. The stiff LF spring setup does not work well on tracks banked over 10 degrees. However, tie down shocks are becoming less and less desirable. The following information applicable for most oval track Chrysler styles mono and multi-leaf leaf spring applications with the sliders mounted on the rear. by racerx1622 Mon Aug 29, 2011 11:27 pm, Post If those desired angles are different, then we term the setup unbalanced. Try to install shock rates to complement the car's setup. The message I get from those who have worked this trend for a sufficient number of years is one of the following two types: 1) a continuing and constant search for balance in the car and a loss of success on the track, or 2) a returning to the more conventional setups because they have experienced number 1 above. Installing the leaf spring directly to a fixed axle seat (no upper or lower rubber mounted pads which are common on GMs) will increase the overall spring rate, wrap-up rate and lateral rate, as well as the braking rate. If the geometry is such that the rear end is made to steer on turn entry so that the RR wheel is farther to the rear than the LR wheel, we have rear steer to the right. We should start with the mid-turn handling because problems that affect the car in the middle can also affect the entry and exit. Knowing this,Landrum Springas elected to rate, dyno, print (numerical as well as graphical data), engrave each springs serial# and rate. The advantage of this style is that the spring is lighter than the multi-leaf. Designing a spring also requires considering the wire size, O.D., I.D., free height, compressed height and static loads that are to be expected on each spring. If we can get the car to handle well in the middle, then we might have already solved some of the entry and exit problems, too. With this system you can run a softer rate on the top and a stronger rate on the bottom. Steering Geometry When it happens on the left front, the chassis will lose bite. Anything over 3 tends to be excessive and decreases forward bite due to the fact that the torque wrap up or forward thrust resistance of the rear end increases, therefore not allowing any wrap up or torque dampening to occur. Also, excessive torque of the shackle bolts will increase the installed rate. It should help your 60' times by letting the rear squat more at the line before the suspension loads up. Furthermore, with the incorporation of the coil-over spring/shock type suspension, the coil spring and shock ratio is close together and operates as one unit. This eliminates the inaccuracies and confusion of trying to figure out how each spring is rated. The springs are tall and constructed from small-diameter, high-tensile chrome silicon wire, providing the correct rate for the listed application. When it happens on the right front, the chassis will gain bite. On some tracks, with cars using Detroit Locker rear differentials, the accelerating portion radius will be larger than the mid-turn radius. The difference is you also use a stop mechanism lock out nut that stops the travel of one of the springs at some point during shock travel to where the car is then riding on only one spring. In the QA1 part numbers, which is first - compression or rebound? Smaller gains can come later on after the more important aspects of setup are resolved. 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. Next, tune the entry balance and then tune the exit balance. So in some cases, using chrome vanadium for higher rated springs is a better choose than chrome silicon. If the car is diving excessively under heavy braking, the RF wheel will lose camber quickly and its tire will loose traction. 2022 Landrum Performance Springs.All Rights Reserved. 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. On a metric four-link car, the four control arms determine the rear moment center height too. on the right rear, you should not install a taller spring on the left rear with the same spring rate as the right rear. These desires are directly influenced by the spring stiffness, location, and spring split, the sprung weight the system has to support, along with the moment center locations and other settings. Leaf Spring Conversion Chart. 9. There are ways to do that without changing the handling at other points around the racetrack. Because of restraints in design and the need for geometry controls for moment center placement, we have to live with those properties. All the driver knows is that the car is loose. Impact from tire hopping or grazing the wall can bend or unroll the main leaf eyes. At some point, we take in enough information to allow us to avoid the mistakes of the past and get ahead of the curve in setting up our asphalt cars. And, some aspects of chassis setup build on other aspects. Clench clips (see Figure 2) have been proven to maintain a more consistent spring rate because of its ability to retain its clamping force. Verify the leaf spring for consistency in the arch. If we arrange our control arm angles, from a side view, for antidive, then as the car dives the upper BJ would move to the rear and the bottom BJ would move to the front. Rear Geometry One negative scenario is the fact that the right front compresses at a faster and compresses more than the left front, the chassis may tend to gain cross. endstream endobj 209 0 obj <. Most companies incorporate a metal tag denoting the theoretical rate of each spring. The track at Santan Junior High School is missing some info Please fill out the form below if you have the local knowledge to help your fellow runners. Once you have evaluated all of the above and feel fairly confident that the car is set up correctly, you should then work to tune the transitions into and off of the corners with the shocks. by RCJ Wed Jun 22, 2011 8:36 pm, Post (2.) Complete kit includes a pedal with a built-in return spring and throttle stop, universal firewall bell crank. Still, teams want the most they can get out of their cars and if all of the above nine items are in order, by all means, go ahead with aero tweaking. When not racing, keep the springs unloaded by simply placing a jack stand under the chassis frame rail. If the same stiffly shocked corner is in rebound, less of the overall load will be retained by that corner, and its diagonal corner as well, during the rebound cycle only. The spring rates and spring split across each axle help determine the desired attitude, or roll angle of that end of the car. Decrease both Front Spring Rates. The number one reason a car will be tight and not want to turn is because the front end is not designed properly. by racerx1622 Thu Aug 25, 2011 5:51 pm, Post e; Most top shock technicians will be able to help you select the proper shock rates to go along with your particular setup related to your type of racetrack. Sliding the MC left and to the inside of the turn makes the suspension softer. Driving style plays a major role in the life of a leaf spring. Excess stagger should never be used as a crutch to help make the car turn if it is tight. Leary sets the wedge in the springs and then adds additional wedge with 3-6 turns of preload and sometimes has winning success using 9 turns. Free rateis the rate of the spring when it is out of the chassis. Stock cars using the metric-style four-link rear suspension usually need to do this just to achieve a balanced setup with the high rear moment centers in those cars. Leaf springs are the oldest form of suspension in racing. Leaf Spring Suspension Performance Tips. Although the camber change is quick and the wheel returns to normal camber settings a short time later, once the push starts, it is hard to stop it without slowing down. Furthermore, the leaves should include Teflon inserts on each end to reduce inner leaf friction. The track radius used to determine stagger matters the most where the car will be accelerating. I talk to lots of racers representing every form of circle track racing in every region of the country and beyond. Coil springs are the most common used spring in most all motor-sports today. It helps to install brake bias gauges and then adjust the amount of pressure front to rear. If we are loose going into the corner, the LR shock may be too stiff in rebound or the RF shock may be too soft in compression, which transfers load off the LR tire on initial entry under hard braking. As a result, not every spring will come out exact. The opposite occurs when the springs are mounted outward (closer to the wheels). For instance, a J200 (5o.d. In the common asphalt setups of today, where we use a larger sway bar and softer springs (BBSS), the presence of Ackermann effect could be more detrimental. Leaves that are tapered on the ends are generally used for mass production applications which do not require the close tolerances and consistency in the spring rate that racers demand. Recommended torque is 20 lbs. If all else were correct, such as alignment, Ackermann, setup balance, and so on, and the car was still tight or loose, then the crossweight percentage is probably wrong for the weight distribution in the car. One is called Stacked springs because all you are doing is stacking two springs in series, with the same or different rates, to achieve a longer spring that is softer rate than either of the springs used. We will look at each phase of the corner and offer handling remedies based on the phase they affect. Forged ends are only desirable when mass production of a loose tolerance spring is acceptable, for example, the agriculture or industrial industry. Multi-leaf springs used for racing should incorporate leaves that are diamond trimmed on each end, not leaves that are tapered on the ends. by 72firechicken Wed Jun 22, 2011 3:46 pm, Post But the most useful rear steer will only occur on acceleration and not at mid-turn. 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. A tight condition is the number one complaint from drivers. Hopefully the data contained in these pages was informative. dQ#A$70 Q,6D|B@1" hKF? A too-tall spring may be lowered by cutting off a portion of a coil (usually around 1/4 to 1/2 of the coil). Make sure your brake bias is tuned correctly. Decrease the Pre-Load on the Front Stabilizer Bar. Measure from the main leaf to the datum line. You can decrease the spring rate by increasing the angle, or increase the rate by decreasing the angle. It is the purchasers responsibility to order the correct products through their personal racing experience. It is this sliding scale situation that determines the stiffness of your front end. Tapered end leaves have a gradual decrease in thickness on each end. Another way to stack springs is to use the dual system. Through interviewing various teams, we found that current spring suppliers were using many various methods of rating coil springs. We hope you enjoy shopping at Circle Track Supply, Inc. Here is an explanation of balance related to the dynamics of the race car. If all of these issues are evaluated and corrected, then you can move on. Although these changes will alter the height of the car, the spring rates will be unaffected as long as you stay within the guidelines. There are four basic types of leaf spring systems in the racing industry today. endstream endobj startxref In addition, banding clips are frail and tend to break under impact or stress. "There are two or three basic setups which are really simple, compared to bar car setups. 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. These set-ups are to provide a reference only. To check if the spring and jack plate is making true contact, simply inspect the contact points. This leads to bent shackles, warped sliders and misaligned axis points. Chrome silicon generally comes only in no larger than a .625 size from wire suppliers in the USA. Moreover, accurate spring changes will allow teams to be more progressive in their test sessions and eventually reflect in their qualifying efforts and then onto the race. Use a Smaller Front Stabilizer Bar. One way is to have a rear spring split, where the right rear (RR) spring has less spring rate than the LR spring. This simple task will increase the life of the leaf spring dramatically. Different bushing diameters and unleveled floors will lead to inaccurate measurements. Balance the Front and Rear stiffness. We will need to go through a checklist to eliminate some familiar problems. However, the negative effects of these bushings greatly outweigh their intended purpose. 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. In addition, the leaf spring suspension is more forgiving on chassis set-up errors. No one including us can guarantee every spring to rate out exactly. As each season comes along, our knowledge of what we need and desire grows. I plot them like its a ladder bar (if its right, wrong, backwards, I dont care it works for me) and had it setup with an IC of around 30 (20 inch front segment, 8 inchs off ground) With this setup the car went 9.98 with a pump gas small block and some spray but it was killing the tire. Carrying an inventory of A-Arm lengths gives you more Instant Center Adjustment choices right at the track. Softer grades tend to stretch under stress created while tightening instead of maintaining compression between the spring and axle perch. In turn, the life of the spring and the number of cycles is reduced. By Bob Bolles, Circle Track Magazine . HOPEFULLY THE INFORMATION CONTAINED IN THE TECHNICAL AREA HAS BEEN HELPFUL. 6. Fiberglass Leaf Spring The fiberglass leaf spring is made of a mixture of plastic fibers and resin; it is lighter than all other springs. In some instances the manufacture may have to choose chrome vanadium wire, instead of chrome silicon. What I hear I feel is representative, although those who dive head first into the BBSS mix not because of a perceived and measured expectation of success but because of the "see monkey, do monkey" attitude, will never share what they are doing. It is not advantageous to have the rearend steer to the right at any time on asphalt. These theoretical rates are just that, Theoretical. This is why the driver and the tire temps showed no change. Since the braking forces are in the opposite direction, there is a serious resistant force created which helps prevent the front suspension from moving in compression too quickly while braking. With the advent of the BBSS setups, both front wheels experience a great deal of camber change as the chassis dives 3 inches or more in the turns with an accompanying reduction in chassis roll. Put the tires on it you are going to race then rotate the tire and scribe a line all the way around the tire.Be as accurate as possible.After you have scribed both tires measure 4'' off the ground the distance between the scribed lines on the front side of the rear end then measure the distance between the lines on the back side off the rear These methods, good or bad, can be confusing at times. Let's stay with the circle track lingo. 10. I don't really encourage that method. The more third link angle you have, the more antisquat there is. LANDRUM SPRING is not responsible for any incorrect information listed. Slinging the car into the corner or spinning out puts an extreme amount of lateral force on the springs which in turn, causes premature failure. Decrease the RF Spring Rate. Some manufactures even feel and state that racers should monitor a springs free height instead of its rate. The influence of the location of the front MC can be compared to a sliding scale. We also want to make sure that adjustments to other segments later on do not affect the mid-turn handling. The overall rate and the layout of different shock rates on the car can greatly affect the weight distribution, and therefore the handling, in the transitional phases on the racetrack. Cars that don't turn well are very likely to have poor MC designs. 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. Shock rebound rates need to be adjusted to allow the LR tire to stay in contact with the racing surface. DESIGN: Most coil spring failure is directly related to the design of the spring. This will produce a lock-up or binding effect and the car will perform erratically and unpredictably. Do not seek aero downforce at the expense of aero drag increase. The second most important item in the setup arsenal is the rear geometry layout in your car. Adding or removing as little as 50 pounds can also make a difference. This system involves riveting the clips onto the leaves; the advantage is in preventing the clips from sliding up the leaf and becoming loose. The amount of resistance is directly related to the degree of side view angle we put in our control arms and the amount of brake force used. The settings, including the moment center location, really do dictate how all of the other parts and pieces of setup will work. If the transition is abrupt and the top of the track drops to match the inside edge elevation, then the RF will follow the drop-off and unload the LR wheel. The rear end should be at right angles to the chassis centerline, and the right side tire contact patches should be inline. If the front is diving under braking then add anti-dive to front suspension. If there are any marks or distortions on the spring they should be discarded. LIT-718 80291 1997 - 2004 Mustang Radiator. In situations where the exit portion of the track provides less traction and/or the corner is more flat, we might need to develop more rear traction upon acceleration. CTS SUPER DUTY LEAF SPRING ROLLER STYLE SLIDER-CHEVY OR CHRYSLER STYLE. 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. Maximum U-bolt torque for 1/2 diameter, plated U-bolts are 45 lbs. Urethane and aluminum bushings tend to transfer more energy and loads directly to the spring. One should use the same free height, but change rates. That simple test has helped many teams quickly determine the status of their setups so they will quickly know which direction to go when tuning the mid-turn handling. I don't get too many reports of continual, repeated wins and successes. 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. The wine-and-cheese crowd refers to these as oversteer and understeer. The once tight condition now switches to loose as the front gains grip from excess steering angle. When the LR tire is the coolest on the car, the rear spring split may be too much. 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. Also, common mishaps of spilling brake fluid or brake fluid contact from simply bleeding the brakes will deteriorate the rubber and break the composite down; therefore, the rubber will fall out and the clips will be loose and slide down the main leaf. asphalt metric street stock setup asphalt metric street stock setup on March 30, 2023 on March 30, 2023 Engineered to hold a great amount of stored energy for instant weight transfer. Another negative effect of forged end springs is the fact that the chassis settings may change. This is how the spring segments are clamped together. So, with some of the information we have learned over those years applied, here is a modernized version of that article. This prevents undesirable chassis and rear end movement, thus creating favorable synergy between the chassis, springs and rear end. To determine the effective angle of a shackle, pull a string from the center of the front eye to the center of the rear eye of the spring, and then a line from the rear eye through the shackle pivot point. 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. Either of these two can be caused by an unbalanced setup or by running with the wrong amount of crossweight. Listed below are the effects of spring arch. Many times hair-line fractures and cracks cannot be seen without the aid of a florescent penetrant inspection. Causing the right front tire to have a higher tire temp, as a result, a shorter life of the tire. on the left rear and 225 lbs. This puts undue stress on the leaf springs. To fix this, reduce the rebound rate in the LR shock and/or stiffen the compression rate on the right-front shock. This is very "old school" but when applied with a balanced setup, very effective. Put the tires on it you are going to race then rotate the tire and scribe a line all the way around the tire.Be as accurate as possible.After you have scribed both tires measure 4'' off the ground the distance between the scribed lines on the front side of the rear end then measure the distance between the lines on the back side off the rear end.You might get a number from the front like 72 .5'' , the number from the back might be 72.375 this would be 1/8 total toe out.This does not tell you if one side has 1/8 toe out and the other has 0 toe.Putting the axle in the car measureing from the center line ,string it etc..will tell the toe of each wheel.You might think this crazy but I've looked down the side of enough race cars I can see an 1/8 toe with my eyes. Slenderness ratio needs to be considered when addressing the design of the spring. That troubles me. Shocks affect the motion of the corners of the car and therefore the placement of loads during transitional periods. It may take a few test sessions to help you determine your balance, but if you observe the indicators correctly, then tuning the car for dynamic balance can be done. Pitch is the distance between the wires on any given coil-spring. LIT-A950700006 80249N Ford F-150 LightningHarley HE. lowers roll steer (tightens car on corner entry), increase pan hard rate (may tighten car in center of corner), lowers roll center (decreases chassis roll), raises roll steer (loosens car on corner entry), decrease pan hard rate (may loosen car in center of corner), raises roll center (increases chassis roll). This can be caused by several different conditions, or a combination of those. We hope you enjoy shopping at Circle Track Supply, Inc. If the leaf springs hook-up points are installed on the chassis incorrectly the misalignment will produce high stress loads on the spring. We have redesigned our website to give our customers a better online shopping experience. When they are working together, the car is well on the way to a balanced state. The disadvantage is that they produce inconsistent spring rates. Springs with banding type clips (see Figure 1) with rubber insulation produce inconsistent spring rates due to the fact of various durometer hardnesses and the deterioration of rubber compounds. These types are desirable where stock lower control arms are used. The more carbon removed from the material, the more hardness is removed from the wire. 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. In addition, fiberglass springs are sensitive to heat. In addition, the choice of this material will allow a manufacture to wind the spring out of smaller wire to incorporate a larger pitch, which will inadvertently allow more travel and produce a lighter weight spring. We must develop ways to create more rear traction on acceleration only. The bottom line is that at mid-turn, each end will want to roll to its own degree of angle. The setup that will stay consistent throughout the race is the one that wins, and balance provides that consistency.

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