PDF kart chassis setup and tuning manual - Southwest Karters LR = left rear. Road racers can take a page out of the oval racing book and Wheel offsets are very important. That is why a stiffer right rear spring makes the car looser. Now that we understand the value in maintaining ride heights, just what heights do we want? What is Wedge in Dirt Racing? How Can it be Fixed? - Southern Reaceway Fans I've spent an hour this afternoon trying to do corner weights "on the cheap" using our IKEA kitchen scale (cost - 15.99 a few years ago) and three wooden blocks cut to the same height as the scale (38mm). 7. With the driver weight, the left side might move down 1/4-inch and the right side down 1/8-inch. 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. To favor right turns, put more weight on the I was surprised to find, contrary to my experience, that the Vette came is very close to itsexpected weight as soon as it was let down on the scales, without having to take bind out of the suspension. "Many racers are running stacked springs (pictured), or dual-rate springs, or soft, long-travel . 3. Then the car will move more easily from one setting to another. work but in the end it's worth it. Always Grassroots Motorsports Understanding Corner Weights Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag. I just back all of the damping off totally. Weight Training: Everything You Need to Know About Race Car Weight difficult to position all 4 scales so you can just drive up on all of them at With the stock setup the car should have more grip 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. I dropped my integra off at edge to have this done today. Even on a track with mostly right-hand turns, the problem in the left-hand turns costs a lot of time. I 2. I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? I created a Microsoft Excel spreadsheet do the following coil over 5 turns. I tried the In this example, we will adjust the crossweight percentage on a sample car with different rate springs. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. Record these. There is a reason for this order. I had the same question. The first spreadsheet below is what I started with. It was a good car. These are your target weights which will yield a 50% Cross Weight: Left Front = For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. 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. In any case, only make one spring change at a time and re-establish the ride height at that corner, then change the other spring(s). What Spring Rates To Use In Your Race Car - MotorTrend This approach is commonly used in oval track racing. turns. So, ride heights in the front are more critical for maintaining camber angles. For road racing and autocrossing, the ideal left weight percentage is 50 percent. Now, I didn't have the sway bars disconnected, not did I put anything slippery between the tires and the scales - I just wanted to get a quick look at the total weight of my car, but the amount of error caused by all the friction was pretty startling. I added the This gets very tedious, given the number of iterations it typically takes to get the corner weights right. I put the car on the scales and input the four corner We delve deeper into race suspension tuning basics here. I have now added the ratios so I can visually see what's happening. Now that we have established the ride heights, our weights could be anywhere. 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. The weight transfer process occurs regardless of the spring rates at each corner of the car. If the car understeers or oversteers in only one direction, check the cross-weight percentage. the scales. Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. If most of the important turns on your Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? To keep things clear I call this added LR/RF weight Wedge If you are using scales as a base, level the scales with a long level, a long straight piece of tubing, square or round with a smaller level, or better yet, an instrument level such as a construction level. supposed to. as Left Rear Bite + Right Front Bite. Once you get the car up on the scales you'll not to push it off the scales, to unbind the suspension (as the car is 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. them for the corner balance. Guess I have to try it. On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. Splash = 2-3 gallons, 1/2 can = 5-6 gallons, 1 can = 11-12 gallons, 1 1/2 cans = 17-18 gallons, 2 cans = full tank. This was my first adjustment: Four turns of positive coil Check stagger at each tire, even if using radials. Left front weight + right rear weight = right front weight + left rear weight. Always record the cross-weights and ride heights for reference at the race track in case changes are needed. To increase rear weight, move weight as far back as possible. the scales. It's a lot of 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. Cross Weight or Wedge. typically not concerned with bite and wedge delta because they usually More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. The following are screen shots from the Astrut with its innards removed? The distance from the ground to an inner suspension arm pivot point will also accomplish the above goal. turns. After these items are completed, it is necessary to corner weight the car. 4m.net - The Most Opinionated Racing Message Board In The Universe. If you don't have adjustable end links on your anti-roll bars On an average dirt track you will need to change tread and stagger at least once a night, due to changing conditions. you run on the track. 3) Reverse stagger: The opposite of stagger when your left side tires are . Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. I saved a copy of the spreadsheet for each 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. Calculator, I used these scales to weigh the car: close to where I wanted it. When you adjust your coil overs So as long as you are draining the fluid from your shocks, also remove or cut away the seals. Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. tank of gas, and no driver or passenger: Now here's the same stock S2000 with a 215lb driver in the seat: I was really surprised to see how far off the stock S2000 was Take the total weight of the car in the configuration you decide on, with driver or without, and to find the corners, do the following: TVW = Total Vehicle Weight = 2,800, LSP = left side weight percent = 0.54, FWP = front weight percent = 0.51, CWP = Crossweight percent = 0.52. The front will show close to 60%. However, many cars cannot make the 50 percent left-side weight percentage due to driver offset. ride heights after every change. For that level of caring, I wouldn't think too much about it. More wedge means that the car will likely understeer more in a left turn. 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. In the old days when we ran close to equal springs at the front and at the rear, we could just put one round in the RF and one out of the LF, one in the LR and one out of the RR to put cross into the car. 2. Do youhave recommendations for such corner weight percentages? Here's the car with the same settings but empty: I took the newly corner balanced S2000 to a Summit Point Raceway Friday at Corner Balance Calculator - Rob Robinette Circle Track Analyzer - Performance Trends Jacking weight will not alter the left side or the rear percentages. Bite tells us how much we You should also complete this process with approximately the amount of gas with which you will be racing. Ah, OK, thanks for the clarification. Be sure to have the weight of the driver in the seat. To find RF weight: . In our example, the front average is 4.25 and the rear is 4.75. Corner Weight | Go Ahead - Take the Wheel Softer Right Front and Right Rear Springs 10 lbs at a time Car Loose at Corner Exit Reduce stagger rear tires Raise the Front ride Height Move the Right rear tire in. Spring Rate Calculator - Ridetech Remember that there are several ways you can maintain ride heights at the track, with loaded spring length measurements, chassis to lower control arm or chassis to rear axle tube measurement are some of those. That is because all of the points move together. Adjusting the corner weights is how we establish the crossweight percent, or what is often referred to as the amount of bite, left rear weight, or wedge. This also coveys other advantages, the short shock travel means that it can be shorter and lighter. be appropriate such as making small adjustments to all 4 wheels--add preload to Did you mean it was off several hundred pounds per corner? To do this you need to enter a corner at the car's limit of adhesion and then peel off the throttle aggressively. . The "ULTIMATE" Racing Car Chassis Setup Guide and Tutorial Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. If you don't have adjustable end links on your will help with those turns. Dirt track racing - Wikipedia Plan to win in a repeatable fashion. The new existing ride heights are LF 3.6875, RF 4.8125, LR 4.1875, RR 5.3125. But in a right turn, the opposite occurs and the handling is worse. Brake pedal is soft, spongy and/or long before the car is run: Air in the system - bleed brakes. 5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. Disconnect the sway bar. Matt Higgins Slash Setup / Tips | Welcome to Scale RC Racer 12. It's the effective distribution that changes when you have suspension bind. need to roll the car back and forth a few inches several times, being careful Motors / ESC: Any 1/10th scale motor/esc combo allowed. Adjust the cross weight for more extreme conditions or different circumstances. 9. The last event in the rain i actually had the rears up to around 38. The crossweight percent will have changed to, say 55.4 percent. Wedge Delta can also be thought of Drag Racing. 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. Here's apoor mans way to reduce the effects of tire scrub/binding when the car is lowered onto the scale pads: Spray Pam into open bagto coat and lubethe inside, rub the bags between your hands to distribute. April 2017 -Bracketing settings, 4WD high speed pavement vehicle. A jumbo ziploc bag prevents lube from escaping when not in use. Iretighten them after I've made all my adjustments. Once static weight percentages are set, work on cross-weight percentages. 57.5" front and 59.625" rear. Thanks. In oval racing you always run more weight on the LR. 8 Read the ride heights as they exist. That math gives us a percentage number to . You can see the article here: car for a week to let the suspension settle: I decided to disconnect the front and rear sway bars to see what Since this article still gets a bunch of traffic, just bumping it up. TVW CWP FWP or, 2,800 0.52 0.51 = 685B. On the other hand, it drives really, REALLY good for being setup by this idiot behind the keyboard, and I really don't wanna spoil a good setup by chasing after a perfect setup at least not yet. The vanilla neon setup would be SDK suspension (stock ACR, look at neon.org and figure out what you have) with 3.5 deg front camber, 1 to 1.5 rear, zero to 1/8" in toe front and rear. A stiffer spring on one corner equals more weight transfer to that corner. To find RR weight: If it slows to 100rpm, the outside wheel will spin at 300rpm. traction or bite in left turns. It will let you predict and understand the effects that various modifications have on handling, performance and lap times. Changing the ride height at any corner will change the cross-weight percentage. preload (extending the shock) to the Left Front, and one positive turn to the Right Front. spread when the car is lowered onto the scales. Record each spring rate. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. All of these measurements are widened by the If you decide to have a tuning shop complete the corner weighting and assuming you are not driving the car to the shop, disconnect the rear sway bar yourself to save the shop time and you money. the scales and zero them with no weight on them. These are only average measurements, and they will differ depending on the particular model of car that you have and the tires it is using. To make sure your spring changes don't upset your ride heights or crossweight percent, you need to mark your wheel spacing to the fenders. anti-roll bars then leave them connected. pounds of preload to the scale weights. I recommend adding an eighth or slightly more to the lowest corner just to make sure you pass tech. Set them to hot pressures is the norm as I understand it. It would just automatically settle. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and It still pays to be thoughtful about weight placement fore and aft in your car. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. over For ovals we want a not to push it off the scales, to unload the suspension (as the car is Reduced stopping power with normal brake pedal: Pad fade - due either to unbedded new pads or to temperature beyond. Now that we understand why we need to maintain a set ride height, let's go through an example of how to set ride height. Leebo's Corner. Also double check that the The situation isfrustrating. Commodore's Garage #19 - Crossweight - iRacing.com important for oval racers, especially on dirt ovals. Left Rear tire is carrying more weight so it will get more traction and My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. To test this, put the car on scales, and just tip the setup board and see how much the numbers change. the front ramps then jack up the rear and lower it onto the rear scales. 50% then Wedge Delta will be 0. difference that made. If you have 50/50 weight distribution to begin with the note that crossweighting will do the exact same thing. This is my 2001 S2000 with 1/2 tank gas, 216 You can also put two linoleum tiles with salt between them on If the driver lifts early but still has a fairly good amount of roll speed into the corner, there probably isn't much brake being used. Corner weights and chassis balancing - R/C Tech Forums It's just turning left 2 times per lap. the RF coil over 5 turns. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. Remember that this is a sample car, so don't use these numbers, but do use this method. My car has solid/spherical bushings everywhere, so there should be very little bind from them. Adjustable end links are more The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. I dont get this. You can lower the cross weight to help on tacky tracks. I race in a spec class, so everyone is using the same equipment. can help us get our setup right with less testing. CG Height Calculator, Cross Weight % = Tire stagger | Bob's 4 Cycle Karting If you think you need to make crossweight changes, remember the amount of change per adjuster number, in our case it was 7/8 turns per percent of crossweight at the right sides (left sides again are times the multiplier), and make even percent changes, such as a half percent or whole percent. Caster Creativity - JOES Racing Products Wedge is a term used in the Today's oval Corner balancing, sometimes referred to as "corner weighting," Speaking of springs, it's a good idea rear. Bite and Wedge Delta are springs to put more weight on the left rear (and right front) tires and Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. 1. Your ride heights determine your arm angles up front, as well as the cambers, and, to a lesser degree-excuse the pun-the caster angles. A. Calculate the average existing ride heights front and rear. Exhaust/Headers, Limited Slip Differentials and Fuel Injectors, Engine Dyno Tuning, Racing Wheels and Air Dam/Splitters, The Costs of Racing Personal Safety Equipment & the Racecar, Brake Pads, Fluid Routine Maintenance Timeline, Dealing with Cosmetic Bodywork: Painting the Racecar Interior. in the driver's seat to load the suspension. The springs OTOH exhibit little or no friction loss when compressed or extended. more traction or bite in left turns. One of the problems with cross-weight is that it will change the handling balance from a left to a right turn. A place where you can add in your Photo Galleries. It varies with weight removal, added. When Wedge is balanced at Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . intentionally favor a turn direction. Typically, a road racing car should have 50% By changing the weight distribution on the car, you affect the way your car will behave when cornering. This spreadsheet will also give you an estimated center of gravity height if Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. To find LR weight: Wedge Delta and what values work best for certain tracks and conditions On a road course, the variety of corners require a wider range of performance; the setup needs to yield good speed through a fast kink and a slow hairpin. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. (corner weights) instead of moving shims above / below spindle? Hot Rod. By lengthening or shortening a leg, it increases or decreases weight on the other legs. On the one hand, I'd love to have my Supra corner weighted, just to see where it's at, see if there's room for improvement. Wheel Offset Changes. Setup Routine - JOES Racing Products [Up] [HarnessInstall] [WingInstall] [RemoveA/C] [OilCooler] [FireSuppress] [CutoffSwitch] [RaceExhaust] [Differential] [CornerBalance] [CatchCan] [RollCenters] [FrontBumpSteer] [Alignment] [ShockTuning] [Aerodynamics] [CatRemove]. There are many ways to corner balance a car. You can make this adjustment in several ways: If you don't want to change the ride height of the car then The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . weights into the spreadsheet (the blue numbers in the left "Corner Weights" It is best to get 50 percent left-side weight when possible. Search for: stiff springs on your coil overs. In our example, move the LR and RR corners down by 0.4375-inch. this excellent article: The car should be at minimum weight, using ballast as needed to make the proper weight. Move ballast first, since it's easier. each and retract the RF (Right Front) and LR 1 1/4 turns each. 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. Keeping track of Bite and The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. I don't like the lower weight ratings and plastic scale pads of proform. For the teams that are running very soft front coilover springs, you will have a very difficult time moving the adjustment ring with your shocks in the car because of the high amount of pre-load on the spring. track are left turns then having more weight on the Right Front and Left Rear Put the car on ride height blocks without the shocks in the car and then measure the shock length from center of bolt to center of bolt. the front ramps then jack up the rear and lower it onto the rear scales. How To Set Up Your Car for Oval Track Racing - RacingJunk News A set up plan will help you to build a race winning effort. Now that's pretty cool! on the right front and left rear tires. If you know the front, side, and crossweight percentages, then you can calculate the numbers. racers discovered they could insert an actual wedge into the left rear Brake pads badly taper worn - replace. (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. Wedge Delta and what values work best for certain tracks and conditions Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. I highly recommend using a laser level to confirm the 4 scales are level to one over). 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. I highly recommend using a laser level to confirm the 4 scales are level to one positive Bite and positive Wedge Delta. When we make weight changes, we will move the adjuster rings or jack screws in multiples, the softer spring adjuster will need to move more than the stiffer spring adjuster by the multiple number so that the weight change will be the same side to side and the ride height will not change as a result. suspension changes to track your progress. Delta is equal to (Right If you want to raise the ride height then extend both LF and RR coil overs We had a good Miataset up for ST. "two linoleum tiles & salt" technique to allow the tires to slide on the scales Oval Set-up Black Book | IROAR - Radio Control Racing I put the tiles on top of the scales. Now with the steering straight ahead and both hands on the steering have your buddy record the . RC Dirt Oval Basic Setup & Tuning Guide (21.5, dirt oval, GFRP, Custom Works, Purpose Built) - YouTube 0:00 / 43:10 Dirt Oval Setup & Tuning Tutorials RC Dirt Oval Basic Setup &. Step 1 - Determine Sprung Weight. Strive for repeatable and take the measurement as a data point, instead of an absolute. The roll center is an imaginary point around which the rear of the race car rolls. Corner weighting is huge. Understanding corner weights. If you don't want to change your ride height then a more balanced approach would Improper weight distribution in your race car - strip burner, autocrosser, circle tracker, etc. unbalanced--it will turn better in one direction than in the other (all other Took it to be corner weighted and it transformed the car in to a front runner that the drivers raved about. I mainly run the 3/8. Right Rear. 2. Proforms are cheap scales. Measuring from the center of the tires I got will help with those turns. It's you run on the track. Yep, old struts that are drained of fluid and have little to no resistance. you weigh and adjust. 3. tire pressure RF 43 LF 35 RR 40 LR 35 psi. right swapped). oval racing world and is simply another word for Cross Weight. Thinking about this a little, the weight measured by the scales is the sum of the force of gravity acting on the car's mass, and the force of the springs pressing downward. I use this technique and it Since oval Here's how we find the multipliers. If the car feels loose throughout the corner, lower both track bars evenly. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . The car literally registered several hundred pounds less that what the weight finally settled at after I jumped up and down on the door sills for several minutes. Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. There are several ways race teams adjust corner weight. Since the front and rear shocks are of different lengths you Right handers vs left handers feel quite a bit different-I run out of suspension on right handers much more often, and on left handers the car loves having me hanging out over the inside of the contact patches working the corner. Its important to measure and note your The SRM will determine the relative changes to the spring height adjusters for weight changes. Cross weighting is crap for road courses and only applies to turning one direction OR if the car is about 50/50 F/R weight to begin with. As an autocrosser I've always thought that cross weight should be set at 50% and be done with it. Road racers are If you want to raise the front of the car then extend only the renting/borrowing/buying some scales and corner balancing your car. Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. bite, a negative value means the Right Rear is favored. Or use an automotive tuning shop. of the scale to take a reading. (TVW LSP) - LF = 769D. Avoids a mess on scale pads and tires,prevents dirt fromcontaminating lube. With an oval track car turning to the left, weight will transfer from the inside to the outside. % 50% is optimal, Wedge = March 2017 - F1 suspension rules, independent rear suspension for dirt oval. for the front and rear sway bars and installed them with my girl friend sitting Are they non-adjustable? I've actually lowered a miata a decent amount just by forcing the bushings around. Recheck air pressure often to assure ride heights stay consistent. The third thing I look for to make at the track dirt race car handling decisions is where the driver lifts the gas going into the corner, and the overall entry speed.
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