Here we see the difference...
Here we see the difference between the more conventional setup for an asphalt Late Model car running on a medium-banked track. A team might try the BBSS setup utilizing softer front springs and a stiffer RR spring. The large bar reduces the front roll angle, and the large rear spring split also reduces the rear roll angle.
The problem that has surfaced when using the bigger sway bars in conjunction with softer front springs is the search for balance. Even if a balanced BBSS setup is a bit faster than a balanced conventional setup, the balanced conventional setup will always beat an unbalanced BBSS setup and vice versa. The unbalanced situation is reversed in most cases with the BBSS setups. In the "old" days, our setups were unbalanced such that the front tended to roll less than the rear, putting excess load on the right-front tire. With BBSS utilizing a stiff right-rear spring, if the Panhard bar is not set correctly, the front may tend to roll more than the rear, putting excess load on the right-rear tire. In reality, it can easily go either way, so balance does matter and may be harder to recognize with the BBSS setups.
The RaceTrack Matters
The type of racetrack will largely determine the success of the BBSS setups. Usually, the higher-banked half-mile or shorter tracks do not require the BBSS setups. If the track has quick transition of its banking angle from turn to straightaway, a large bar might not allow the car to adjust to the change.
Flatter half-mile tracks and larger-distance flat tracks offer an opportunity to benefit from the more aero-efficient attitude of the car for better downforce and less drag. In any event, remember that the car must be balanced so that each end is working in unison and all four tires are providing maximum grip, and then your car will be as fast as it can be.
Several years ago, the Busch Series championship was won by a team that ran a very stiff right-rear spring at nearly every track. At that point in time, the sway bar rates had not reached the size that they are now. But, nonetheless, that car was more balanced than most of the other cars it was competing against. The setup used might have looked something like this without the large sway bar. Teams who race cars similar to the Busch cars might be running setups similar to this one with the larger sway bar.