Team Associated 12L4 Setup Tips - Lufaso

There are many variables involved in setting up 12L4 radio controlled racing car that it is nearly impossible to give a setup that will work with all tracks and driving styles. Starting points for the various parameters involved in building and setting up the Team Associated12L4 are shown below. Try the car in its box stock form first, before you make any changes. At the 2005 ROAR Nationals in Tampa, FL, except for lowered rear pod, I used the car in the box stock form (damping discs, etc.) to win the A-main modified. At the IFMAR worlds (5th place), I used the stock chassis and front end, with Yokomo option parts (rear pod) to allow the use of smaller rear tires.

Set-Up sheets in Adobe PDF format

Construction

Chassis and front armsChassis preparation is very important. The chassis should have smooth edges around all of the outside edges of the chassis. Fine grit (600) sandpaper is an easy way to accomplish this. Each screw that is on the bottom of the chassis should be mounted flush with the chassis, check by sliding a straght edge across the assembled chassis. If the straight edge contacts any of the screw heads, then that hole must be counter-sunk more or the screw machined down. I prefer countersinking the carbon fiber chassis more than removing material from the screw as the screw may have to be replaced at some point. (Option: To the rear outside edges of the chassis, add telflon tape to ride smoother against the carpet in hard cornering.).
Lower and upperplate Smooth out these pieces similarly to the chassis described above, spending more time with the upper plate at the location the dampener disks ride. If you have access to a mill, these pieces can be milled slightly to reduce weight. On the upper plate use teflon tape to ride against the dampener disk for smoother rear suspension action. On the upper plate, replace the two button head screws on the back with blue anodized flat head aluminum bolts and countersink the plate bolts. This lightens the plate slightly, and allows the body to be mounted slightly lower before the body hits the pod.
Pivot Balls For weight savings, try CRC blue anodized aluminum pivot balls replacing the steel pivot balls. Replace the steel screws for the pivot sockets with light blue anodized aluminum screws (Trinity). If the pivot ball is slightly loose, then the top of the bottom socket can be sanded to tighten the tolerances between the two sockets. The pivot balls should smoothly rotate in the pivot ball sockets. I use the stock steel pivot balls, but polish the steel pivot balls to a mirror-like finish. Periodically repolish the steel pivot ball to make the T-plate twisting actions smoother.
Front Suspension The back of the front arms should be filed at an angle. This will allow smoother steering, without the steering block binding with the arm. This will also allow you to use smaller front tires for lower rotational weight. The front suspension should be free and smooth. The pivotballs should be free and not loose or binding. Use polished titanium kingpins and stub axles. One may also drill out the steel upper suspension turnbuckle to save weight. The top pins are also made out of titanium. Add a thin teflon shim or thin steel washer to tighten the tolerances between the upper suspension arm mount and the upper suspension arm. Check each side for caster, about 2-4 degrees. Generally, if the car has high speed push, add more caster. A total of 5 degrees is the maximum that should normally be used. Note that the same number of spacers will not necessarily result in the same degree of caster on each side on some older pieces, but should not be a problem with the 12L4. Use a camber/caster gauge (Team Associated or RPM) to measure and make sure each side is the same. Use about -1.5 to 1.0 degrees of camber, which allows the tire to wear evenly. Adjust the camber until the tire wears evenly and otherwise do not use this as a tuning parameter.
Rear PodUsethe Team Associated Magnesium motor plate, saving weight compared to the stock alumimum motor plate. If you are a stock race you could use IRS or Yokomo lowered pod blocks to use smaller rear tires. Depending on the t-plate thickness, adjust the 2 or 3 spacers so that the chassis is level with the rear pod, or the chassis is slightly higher that the pod - so the chassis does not rub.
Axle Use the Team Associated stock axle and it should fits moothly into the rear bearing. The bearing bracket may fit too tightly into the magnesium or aluminum motor mount. Excess material on the bearing ride height block should be removed until the fit is not too tight. This will make the rear axle spin much more freely, resulting in higher efficiency. This is very important for run time.
DifferentialA smooth and free differential is a vital component in constructing a good handling 1/12 car. The stock Associated components create a smooth differential. Use the stock Associated Differential grease on the diff balls in Kimbrough gears. Typically a 100 tooth is used for modified and in stock a smaller spur. Generally use the largest spur gear possible possible in which you can still get proper gear mesh. Setting the gear mesh is very important, there should be some play at the tightest spot on the gear, but not too much play. The outside ball bearing used as a thrust bearing will quickly wear out. I used thick oil in the bearing, usually 5-20 weight shock oil. This prevents the bearing from wearing out as rapidly. When finished racing for the day, I loosen the differential so a constant side load is not placed on the bearing. These bearings were not designed for the side loads in a differential and wear out quickly. Consider using a slightly worn bearing for practice, then change to a newer bearing for the races and observe the difference in the handling of the car.
Servo MountsThe servo mounts depends on the choice of a position of the servo, tilted or flat on the chassis. I prefer using the tilted servo positions, use stock adjustable aluminum servo mounts. A flat mounted servo results in increased bumpsteer. Ball studs require spacers underneath, or an offset ball stud to eliminate some of the bump steer.

Tires are one of the most important aspects of the car. As a general rule for 1/12 carpet, good tires to use are Jaco Purple or Double Pink for the front and Jaco Pink for the rear (for modified). One could try Jaco White or Gray in stock for more efficiency. The pink dot tires are softer and tend to wear more quickly. The outside sidewall of the tire should be glued to the wheel with CA glue to keep it from tearing away from the wheel. This also need to be checked after each run. If the tire is starting to tear away from the wheel, clean up the outside edge from with a tire trued and reglue the wheel. A tire durometer (e.g. Maxmod) helps eliminate production tolerances inherent in the synthesis of foam rubber. At important races, it may be useful to "match" tires. A durometer reading can vary over 6 unit on the same compound of tire.
Tire Size is another important aspect. The 'best' tire size is generally the smallest in which enough traction is available for the entire 8 minute run,and maintains enough ride height to meet ROAR rules 0.125" and not drag or rub on track. A smaller tire generally has less rotational mass. Typical tire size ranges are 1.78" to 1.69" on the front for a smooth track. The rears range from 1.77" to 1.89" I typically run the ride height near 0.150" The ride height should be high enough that the chassis is not black after the race.
Tire Rotation A typical road course always has more right turns than left turns if the track run clockwise. This results in the left side tires wearing more than the right side. I always put the larger tire on the left side, because it will wear quicker. This should be checked after every race. I have observed racers with as much as 0.100" difference in right to left tire size. That makes for a car that can not possibly turn the same left to right. Invest in a set of calipers and check tire size after every race, rotating the tires as necessary.
Ride Height The car is riding too low when the front of the chassis/body mount screws are blackened after a run - or the strapping tape used to hold the cells in is blackened. There are several solutions to this, including using the #4 offset ride height adaptors and no spacers underneath the front blocks. Use shim stock or cut out lexan to adjust front ride height.
Tire TractionThe standard traction compound foruse on ozite based carpet is Paragon Ground Effects. There are many important factors in it's use - which can be quite an art form. The length of time the traction stays on is important. For tracks with low traction, it should be allowed to soak in for a longer period of time. On high traction track, a few minutes may be all that is necessary. The amount applied is also considered - in most cases I see racers putting on much more than necessary for the track conditions. This can actually slow the car down as the softer tire tend to scrub more speed - slowing the car down and reducing run time and efficiency. The width of the application is important. The inside 1/4 to 3/4 of the front tires shouldbe done and most often full width on the rear tires. It is also beneficial to change tires each run to prevent traction build up. I usually run only one set of tires twice a day, once in practice and one in a qualifier or main.
Front Springs Most commonly used front springs are 0.022",0.020" and 0.018" depending on the amount of steering needed, bumps on the track, and responsiveness desired. Various combinations of oil or grease can be used as dampening on the kingpins. Note that using lube will require more frequent cleaning and reapplication of dampening. In many cases, it is more convenient to just use the polished kingpins with no lubrication.
T-PlateThe thick T-plate - which can vary from 0.070" to 0.080" thick is a good place to begin for carpet. There is nearly 0.010" production tolerance in fiberglass, so measure the T-plate to ensure what thickness you are using. The thin T-plate is generally used for asphalt Note the thin t-plate is more susceptible to failure and requires replacement more often. The T-plate has the option to use 2 washers or 3 washers between the T-plate and the rear pod. In general, the 2 washers makes the front the back softer, making it better for the bumps and increasing rear traction. Three washers stiffens front toback and decreases traction. Using two washers also increases the chances that the T-plate will become stressed. Look at the T-plate by holding it to the light. If a noticeable color difference is present at the corners, the t-plate needs replaced. I usually prefer to use 3 washers on carpet. I sometimes place a small motor shim (0.010") under the font of the T-plate, which tends to increase rear traction and is often helpful for 1/12 modified.
Damping Very little damping is used initially when I start at a track. Add damping to the rear end to add more steering. I have tried many types of grease, including various oils and diff lubes (the type of diff lube is not important, I use and try many types on the discs). The tension on the damping discs should be very light in most cases (cut the spring to reduce tension if necessary). Remove damping fluid to obtain more rear traction. If a lot of damping is used then a thin T-bar may handle better in extreme situations, but I do not typically like this setup.
Chassis Rake is the single most under-checked parameter in setting up a 12L4 or any onroad car for that matter. The chassis height off of the ground should be measured at 3 distinct locations - the front end between the body posts, the middle nearthe chassis brace, and the middle rear. The chassis should bevery nearly level - to within 0.030" and this is another way to tune the handling. By having the front end lower than the rear,more steering can be obtained and conversely having the rear end lower the the front will create less steering. Note that is valid only toa point.

Equipment

Body Good body choices for 1/12 are the Parma/PSE EXP Speed 8 and Protoform Speed 12. Overall downforce is good in front and rear, which results in better and more consistent handling.
PaintParma/PSE Faskolor is a great nearly odorless paint for Lexan bodies. A wide variety of colors is available. Airbrushing and cleanup is simple with the non-toxic aqueous based paint.
Speed Control LRP Quantum 2is very lightweight and highly efficient. I use setting #4 for throttle, #0 for brake and 0 drag brake. The throttle curve is extremely linear and easy to be smooth with. It is convenient to change wires with the tabs outside the case. The setup is simple, and there are several choices of throttle curves.
Servo & Receiver 1/12 racing needs a very fast servo, but does not need high torque. I currently use a KO Propo PDS-949 ICS, which has a good combination of lightweight and fast rotation speed.
Receiver Pack A 5 or 6 cell receiver pack made of of N-cells is useful in trying to extract the last few seconds of runtime from the main pack. The Rx pack powers the servo and receiver, instead of draining the main pack. Note this may only gain ~5 seconds of runtime, which can easily be lost in one crash. Use a Rx pack to extract more performance, but only use one if your driving/crashing is not the limiting factor (then focus on practice). Mount the receiver so the plugs are near the center of the chassis, so the body can be lowered even more.
TransmitterKO Propo EX-10 Helios with the wheel drop down extension. I use tennis wrap around the grip to make the radio more comfortable to use. A few layers of tape attached to the brake trigger helps provide more sensitivity for braking, which is very seldom used in 1/12 racing. Setting up the transmitter is arguably the most important tuning aids, and often an incorrectly setup radio is the cause of problems. When setting up the speed control, set the throttle Hipoint to 150 (maximum), then set brake to 100. Set steering travel and EPA to 100. Setup the speedo, then adjust the braking down to 80% as a stopping point. Then use the steering balance to adjust the right and left end points to the stopping point on the steering knuckles. Do a turning circle, and reduce steering on the side with a shorter turning radius until both sides are of equal radius. Then reduce the travel to 75%. Adjust the braking feel and steering travel to your needs.
CellsThere are many companies that sell NiMH, but if you are a beginner you do not need awesome cells and can get good performance by buying lower runtime/IR/voltage cells. The key is to learn to mechanically/technically setup the car. When you are driving perfect lines and not crashing for the entire 8 minute race then the better cells will be beneficial. Try the Reedy GP 3700, or better yet, the VTEC 3800 and you will not be disappointed with the performance.
Battery Charger The LRP Pulsar 2 is an excellent choice with a adjustable current and peak detection limit. Try betwen 5.0 and 6.0 A with 0.005 or 0.010 mV detection. Peak until heat reaches about 130 F.
Performance Enhancement PartsParagon floating damping post - although it is not sold anymore. The stock damper disks function just as well. I sometimes use the shortened aluminum damping post by Yokomo, so I can mount the body lower.

Created October 18,1998
Modified June 21, 2006
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