5. The circle track stock car wants zero camber change-relative to the racing surface-in the right front wheel after the car dives and rolls through the turns. The right upper control arm angle mostly affects the right front (RF) camber change characteristics. When designing the MC location, you need to find the correct right upper control arm angle that will result in zero camber change after the car dives and rolls in the turns, and then keep that angle. The left front wheel will always lose +1/4- two degrees of camber regardless of the upper control arm angle, so changes to the left upper control arm angle can be used to locate the MC range laterally.
6. The entire dynamic MC range for dirt and asphalt stock cars lies between 10 inches to the left of the centerline of the car and 20 inches to the right of the centerline of the car. Moment centers that lie outside that range will be detrimental to the performance of the car. Shallow upper and excessive lower control arm angles (inside points lower than the ball joints) contribute to MC locations that are outside of the optimum range.
The Rear Moment Center
The rear moment center design is fairly simple. Mount a Panhard or J-bar lateral locating device to the rear axle housing and to the chassis, and adjust the height of the ends to raise or lower the rear MC. That's all there is to how the rear MC relates to the roll dynamics of the rear suspension system. As previously stated, the lateral locating device should almost always be mounted to the right side of the chassis. There are exceptions to this rule.
Left Side Bar Mounting
One example where it might be an advantage to mount the bar to the left side of the chassis involves dirt track stock cars, where it is desirable to angle the bar to point it at the RR tire contact patch. This exerts a lot of force and most of the rear weight on the RR tire during cornering. This is sometimes needed for dry slick conditions in order to cut through the dry material so the tire can grip the track surface.
The RR tire will be the dominant tire driving the car off the corners. Mounting the bar on the left side of the chassis can cause both a dirt car and an asphalt car to be inconsistent if there is a lot of traction in the racing surface. This is always true with asphalt stock cars and asphalt race tracks and sometimes true with dirt cars running on a racing surface that has a lot of grip. It would be ideal for dirt cars to be able to quickly switch the mount from side to side in order to be able to adjust to changing track conditions. Most tracks start out the day moist with lots of traction and then either go black slick or dry slick. The left side mount would usually only be necessary for the dry slick condition.
Bar Angle Influence
Angle in the Panhard/J-bar will cause a certain amount of weight jacking as the car rounds the turns, and this can be mistaken for changes in MC location. The rear MC height is always the average height of the two ends of the locating device. During cornering, the bar will always want to straighten out and be parallel to the track surface if it is mounted to the chassis on the right side. If you angle the bar where one side is at a different height than the other, weight will be redistributed to some degree by this effect.
By mounting the bar at an excessive angle for left side chassis mounting, extreme differences in weight distribution can be achieved, if that is your desire. As the car corners, the left end (higher end) of the bar will try to ride up and over the right (and lower) end, and this creates a serious jacking effect. Weight is transferred off the springs and redistributed onto the right rear tire. The left rear tire retains little weight. Most of the weight of the rear of the car is now on the RR tire.