AntiSway Bars

Both front and rear antisway bars are currently available for the A-, B-, and E-Body cars. In some cases, such as the early B-Body cars, a newer design needs to be used since the original design is not reproduced, but that should not be a problem for most project cars. From the factory, Mopar only installed antisway bars as part of an option package, so not all cars were equipped with the proper mounting brackets. This can make upgrading an older car a little more challenging, but the aftermarket has developed brackets and mounts which can be retrofitted.

The original antisway bars installed by the factory were fairly small and had a limited effect on handling. As tire technology improved, so has the need for larger and stiffer antisway bars. The aftermarket has responded with a wide variety of types and sizes of bars, so virtually all of the bases are covered these days. Antisway bars work in the same manner as torsion bars, so once again, the stiffness of the bar is determined by the fourth power of the bar’s diameter. A small increase in diameter will change the stiffness of the bar significantly.

One fairly recent option is the use of hollow tubing for the construction of antisway bars. An antisway bar constructed from tubing can be both lighter and stiffer than a solid bar. Since the material in the center of the bar has only a limited effect on the stiffness of the antisway bar, removing the center of the bar reduces the weight significantly without reducing the stiffness very much.

Rear antisway bars were rarely used by the factory engineers, except for police cars and special vehicles such as the 340-powered E-Bodies. If the rear bar is too stiff, the car will have an oversteering condition, which is generally regarded as unsafe. The relationship between the roll stiffness at the front of the car and at the rear is called the Roll Couple Distribution. Roll Couple Distribution is a controlling factor of understeer and oversteer. To control a car that is oversteering, you would increase the roll stiffness at the front end of the vehicle--install a stiffer antisway bar. The reverse is also true for an under-steering car. Roll couple is adjusted with spring and antisway bar rates. The stiffer end of a vehicle will lose traction first. So if a car’s front suspension is stiffer than the rear, the roll couple distribution will produce understeer because the front end is handling more weight transfer.

For a typical nose-heavy Mopar muscle car, the roll couple should be biased heavily towards the front. Usually something in the range of an 80/20 split works with the front suspension providing 80-percent of the roll resistance. If you have the ability to calculate your roll couple, then that is the best way to select the correct rear bar size. If you’re going to do it by feel, then start with a small-diameter bar, and work your way up.

Shock Absorbers

The shock absorber is an often un-appreciated part of the suspension. Some people buy the cheapest shocks available with their primary concern being the color, while others do understand their importance. If you spend any time talking with chassis guys at a racetrack you’ll quickly find out that they spend enormous amounts of time and money on their shock absorbers. Many race teams these days are equipped with shock dynos, which allows them to test and tune their shock absorbers. While it is possible to buy cheap replacement shocks at any discount auto store, it is also possible to purchase state-of-the-art, double adjustable mono-tube shocks that cost upwards of $700 each. In between those two extremes should be an option for every application and budget. PST carries the Bilstein line of shocks, and has a large range of shock absorbers for Mopar vehicles. Keep in mind, shock absorbers are actually vibration dampers; they don’t support the vehicle's weight. What they do, however, is convert kinetic energy into thermal energy through fluid friction. This involves the flow of oil being slowed down by the valve passages and shim plates inside the damper. The valve passages that the oil passes through are specifically designed to ensure that the vibrations transmitted by the spring are reduced right from the start. With adjustable shocks, there are either one or two one-way valves. The compression (Bump) meters how fast the oil or gas can be pushed out of one chamber to the other. Adjusting for more compression makes it harder for the fluid to be moved when the shock needs to compress. This condition can make you feel every bump in the road.

Rebound meters how fast the fluid is returned to the original reservoir, or how fast the tire can go to full or partial droop. If you have too much rebound pressure, the wheel doesn't go back down after the compression cycle. If it can't go back down quick enough, and you're hitting continuous bumps, the car actually lowers itself and can eventually bottom out the shocks.