Loma Linda University Physical Therapy Acceptance Rate, Cole Johnson Volleyball, Articles C

Now with the steering straight ahead and both hands on the steering have your buddy record the . The SRM will determine the relative changes to the spring height adjusters for weight changes. of its weight on the Left Front and Right Rear tires, and 50% on the Right Front When Wedge is balanced at Useful fabrication tips for just about any project, A crash course in 3D printing | Making Stuff: Part 2, How to make the move to an aftermarket ECU, 10 Must-Have Tools for a Scratch-Built Car, Fitting tires and wheels when an off-the-shelf option isnt listed. TVW - (RF + LF + LR) = 603. the front ramps then jack up the rear and lower it onto the rear scales. You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. Our current setup is as follows - 270 lbs Car & Driver Cross Weight = 48% Rear Weight = 61% Left Side Weight = 51% LF = 56 lbs RF = 48 lbs LR = 82 lbs RR = 83 lbs Dirt adds weight, binds suspension parts and hides potential problems > The bearings come well oiled and attract a lot of dirt. More wedge means that the car will likely understeer more in a left turn. If you want to raise the ride height then extend both LF and RR coil overs Now that we have the front-to-rear rake set, we adjust the side-to-side rake. Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. extra weight is on the left rear and right front tires which gives them more Besides the eventual move to an adjustable ride height set up, I feel like I need 100 lbs or so more spring in the left front. My track width with CE28 17" x 9" wheels "This is called chassis pre-load. Of course you can add too That's all total speculation though. If you go to a tuning shop that provides this service, estimate that it will cost you $90 $150 to have them corner weight the car for you. Jun 7, 2018 #8 . I just back all of the damping off totally. Step 1 - Determine Sprung Weight. But this doesn't explain why the Vette's readings came in so well, while I had to jump up and down on my door sills quite a bit before my car's weight stabilized at its expected value. In order to perform the set up routine the car needs to be completely ready to race. The important thing to remember is that the laws of physics are the same whether you are racing on an oval or a The effect of shock rod seal frictionat the wheel will be reduced by the crank leverage ratio. rod movement from the wheel to the coilovermovement. 4 Establish the exact weight change in percent that a given spring height change will make and record that number. Before putting your car on the scales you need to power up Do youhave recommendations for such corner weight percentages? You can also use this online calculator to compute your corner For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. Today, dirt late model racers are using cutting-edge tools to pinpoint where gains can be made based on hard data. To find LF weight: This obviously means that decreasing cross weight or left side weight Your car may be designed to run different ride heights than these. Maybe I'm over-thinking this, but I was amazed when I got my new scales, and let my car down on them for the first time. Well there is a bit more to it than that. It changed the wheel weights by 10 pounds at each wheel: I finally went too far when I took two turns off the Right Front (went turns. I'm off by 0.1% (see numbers on left side of the spreadsheet). First the tires. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. They are never level. need to roll the car back and forth a few inches several times, being careful Shock Position In our example we will be using the same method with corrections for different rate springs. Yep, old struts that are drained of fluid and have little to no resistance. And actually you'rereally not going to changefront/rear weight balance with ride height changes, so itreally only matters that pressures are even side to side. Shock Angle-measure the angle of the shock installed and at ride height. On oval track cars, cross-weight is usually used in conjunction with stagger (where the right rear tire is larger in circumference than the left rear tire) to balance handling. works well. It still pays to be thoughtful about weight placement fore and aft in your car. You can make this adjustment in several ways: If you don't want to change the ride height of the car then Oval are favoring the left rear tire for better acceleration out of left A. 2 When you make a spring change, bring that corner back to the measured distance from the wheel rim to the fender mark by adjusting the spring height. the same time. I used a laser level to project a horizontal ZJjtX0xiMzjbfb86GLC7qpXBkrSlFeSNVds8hGW514OXUKSxf6kBDIneIL3TzHQV. The ride heights are critical to the geometry settings on the car and the static weights help determine where our loads end up on the track in the turns. in left hand turns than in right turns. Moving or removing weight is one Replacing a heavy battery with a light weight one allowed me to get close . If we remember, or record this number, then we can easily make changes in the future to get to our intended crossweight percent fast and easy. Just make sure none of them are flat or wildly overinflated. I needed 3 linoleum tiles (0.045" thick For pure race cars this isnt a consideration. Multiply the wheel load of 685 times the motion ratio squared, 1.3611 times the shock angle cosine squared of 1.1056 and we get 1,030.8 pounds of spring preload. Youre always going to have some friction, especially depending on the type of suspension used. You need a nice, flat and level surface for the scales. How big is the track? I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? Some racers like to take matters into their own hands-and that's OK. important for oval racers, especially on dirt ovals. Since the front and rear shocks are of different lengths you "If your car is really tight or really loose during hot laps, you have to take a look at the things that are going to make the biggest difference. over (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. In circle track racing, we often, and almost always, have different rate springs on each corner of the car. All of these measurements are widened by the When that time arrives, you walk across the racing surface, into the dirt oval's imperfectly defined center, and meet your instructor. And don't ever believe the track scales. So LF/LR = RF/RR is what you shoot for. "two linoleum tiles & salt" technique to allow the tires to slide on the scales Basically, I don't see much of a relationship between 'static' corner weighing via adjusting spring length and the addressing of fundamental L/R weight imbalance as those difference are what drive suspension and mass motions when moving. The shock length as it is installed in the car at ride height. So we turn the RF adjuster up (to lower that corner) 2.5 turns and the LF down (to raise that corner) 2.5 turns. There is a reason for this order. On a road course, the cross-weight percentage should be very close to 50 percent, within a half-degree either way, to keep the handling balance similar in a right-hand turn compared to a left-hand turn. B. 12. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. This was my first adjustment: Four turns of positive coil Cross Weight % = For information on corner box in the "Ride Height" section of each spreadsheet. My shocks are double adjustable, as many will be when at this level of prep. You need: 1. 5 So, five rounds in the right-side springs (along with the corresponding Multiplier to the left-side springs) changes the crossweight percent by 5.6 percent, which is 1.12 percent per round, or 0.89 rounds per percent of crossweight. Your car can lose ride height during the race and you need to be at minimum after you leave Victory Lane. You could also raise the left front or right rear ride heights to do the same thing. That method keeps the ride heights close to the same. On oval track cars, cross-weight is usually used in conjunction with stagger (where the right rear tire is larger in circumference than the left rear tire) to balance handling. I put the tiles on top of the scales. Would be interesting to see how close to ideal I got it though, given how well it handles already. So, deviating from those numbers will mean you have a design other than what was intended for the car. The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. 3) Reverse stagger: The opposite of stagger when your left side tires are . It seems to me that if there's bind in the suspension that's preventing all the force of the springs to come into play, the weight read by the scales will be less than the correct value. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. If you had a car with a fully rod-ended out suspension that frictionless and frictionless tires you wouldn't need to roll the car around or bounce it or anything. One of the problems with cross-weight is that it will change the handling balance from a left to a right turn. You will have to repeat this every time you lower the car onto That is what you need to read on the spring rate fixture at installed shock length. Free Download Chapter listings from. If your car's diagonal corner weights are not equal then its handling will be Make sure the vehicle is loaded with driver, passenger, and cargo just like you will drive it or . (i.e., if we move the RF adjuster two rounds, then we will move the LF adjuster 2.5 rounds.) Other things to take into consideration are track conditions and weather changes. I put the car on grease tiles so the tires move freely on the scales and then I bounce each end a couple times. . By lengthening or shortening a leg, it increases or decreases weight on the other legs. Are they adjustable? Most people find this out pretty quickly. Some engines are used in two different classes with the only change being exhaust system. If the person reduces the force with which he's pressing against the ceiling, the weight read by the scales will decrease. started with the Left Front because I wanted to raise the ride height of the car over). important for oval racers, especially on dirt ovals. the scales and zero them with no weight on them. Wheelbase: 9.5" min, 11.5" max Maximum width: 10.250" Minimum weight: 57.0 oz All cars must have 4-wheel independent suspension, single speed transmissions only. It's Wedge is a term used in the It was a good car. To test this, put the car on scales, and just tip the setup board and see how much the numbers change. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. You can estimate your car's center of gravity If we subtract the existing ride heights from the desired, we have front low by 0.0625-inch and the rear high by 0.4375-inch. May 2017 -Dirt late model pinning RF & heavy axle tube. rear. of the scale to take a reading. All 4 scales must be within 1/8 of an inch. You can see the article here: That makes every little detail that much more important. you don't use Microsoft Excel. In our example it is 18 degrees. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. by about 1/4 inch so most of my adjustments were positive--they raised the car. R. racing junky Member. Bite tells us how much we Remember that this is a sample car, so don't use these numbers, but do use this method. You can use rubber tires on very specific tracks and seasons. I didn't hunt for that missing 1 %. on each wheel to speed shock adjustment. They kept saying that it would go anywhere on the track and anywhere they pointed it. Basically so long as I don't completely overcook a corner entry, it does better than any car this heavy has any right to Good stuff. Bite tells us how much we Funny. will help with those turns. (corner weights) instead of moving shims above / below spindle? Choose a level spot in your setup area. To calculate cross-weight percentage, add the RF weight to the LR weight and divide the sum by the total weight of the car. the scales. You will have to repeat this every time you lower the car onto I 2. Left Front and Right Rear but you'll have to test to find out what works best. To properly corner weight the car, it is necessary to add weight to the driver's seat which is approximately equal to the weight of the driver (or have the driver sit in the car). anti-roll bars then leave them connected. Grassroots Motorsports Understanding Corner Weights. % 50% is optimal, Wedge = line above the scales and then stood on each scale and placed a ruler on the top This is but one method and I encourage everyone to ask around and find a method that works for your type of car, this one may not be the most efficient.