This car has the panhard bar/track...
This car has the panhard bar/track bar mounted on a serrated mounting plate making small adjustments possible. Always mark a reference height.
Poor Forward Bite-At the higher banked racetracks, we usually do not have a problem with traction off the corners because of the downforce created by the banking. On many flatter tracks, we can never get enough bite.
Bite can be enhanced by several methods: a) soft RR spring (only 10-15 pounds split on asphalt and more on dirt, say 25-100 pounds split), b) use of a pull bar or lift arm to reduce the shock to the rear tires when we get back into the throttle, c) introduce rear steer as the car squats on exit. This is done using the rear trailing arm angles. On a three-link rear suspension, a higher angle (front pivot mounted higher) on the left trailing arm will push the LR back as the car squats, providing rear steer to the left that promotes forward bite.
On a four-bar rear suspension, the arms can be positioned to provide rear steer similar to the three-link as the car squats, usually in the higher holes.
Slow Off the Corner-Fast at End of Straightaway-A car that is sluggish off the corner and tends to be a rocket at the end of the straightaway is geared all wrong. The place to accelerate quickly is not at the end, but at the beginning of the straightaway for several reasons.
Using a lower gear to get off the corners will produce more increase in mph in the first half of the straight than a higher gear will produce in the last half of the straight.
An adjustable screw type panhard...
An adjustable screw type panhard bar mount, shown here, is mounted to the frame and is infinitely adjustable. The entire mount can be moved vertically to adjust the range for a particular application. This makes tuning the balance of the car more efficient.
Even if the rpm max out a little early, the driver can throttle back just before letting off for the corner without losing time. Being easier off the throttle is a good idea anyway and tends to help the transition into the corner. A car that lunges into the turn entry is very hard to control and keep on the bottom of the racetrack.
Fast Start-Slow Finish-From my observations, most stock cars finish a race much slower than they start out. Winning cars are the ones that lose less speed than the others. Consistency wins races. A consistent setup is one where the car is more balanced with both ends of the car, and all four tires, are working together.
Tire temperatures are the primary way to tell if your setup is balanced. Usually the LF tire is the coolest on the car. That indicates an unbalanced setup. Common fixes include: a) softening the front springs-reverse split in some cases, b) raising the panhard or J-bar, c) stiffen the RR spring-only on banked tracks, and/or reduce the "soft RR" spring split, d) move the front roll center to the left.
I purposely did not mention changing the crossweight percent. Reducing the crossweight percent will make a tight car more neutral, but that change alone will not balance the car dynamically to make the LF work harder and the car more consistent. It only serves to make an unbalanced car neutral for a short time.
As changes are made to the setup, adjust the cross weight percent to keep the car neutral in handling balance. When the LF tire temperature more closely matches the LR tire temperature, the setup will be balanced.
The practice of recording tire temperatures is not that common for dirt track racing, so many of those teams look at tire wear to help judge how each corner is working. Use tire wear in a similar way to tire temperatures, the tire with little wear needs to do more work. Be sure that excess Ackermann is not artificially adding heat to the LF tire. That can give a false indication of a balanced setup.
Solve your handling problems in the order that we have presented them here-turn entry to end of straight-away-and your car will produce the consistency that wins races.