Muscle Mustangs & Fast FordsProject Vehicles
Rear Anti-Roll Bar Installation - Rock, But Don't Roll
Installing Wild Rides' rear antiroll bar in Project Stocker.
One of the tricks used by drag racers is to remove the front antiroll bar. While the front bar improves handling around the corners by keeping the nose of the car flat, removing it for strip use drops valuable weight (as much as 25 pounds in an '87-'93). But there's another important benefit. Yanking the front bar frees up the front suspension, allowing the nose to rise quickly for better off-the-line traction.
When connected, the front antiroll bar, which is nothing more than a torsion bar, mounts to the chassis with two brackets and to each front lower A-arm through end links. Once disconnected, a vehicle has quicker weight transfer and greater extension of the front struts and A-arms.
In contrast, many drag racers leave the rear antiroll bar in place. As with the front bar, the rear bar resists roll at the back of the car. This is desirable in drag racing as it helps to keep both rear tires planted evenly. But, as we know, it doesn't always work out this way.
One way to make your car work better is to watch other cars and relate what they do, to your car. The next time you're at the track, pay close attention and watch all the cars. Look at the rear tires and the nose; listen to the engine. Note whether the car hooks and bogs the engine, or whether you see tire spin and hear the engine rev up or "run away." On a good working car, you'll observe the tires dig in, the car accelerates, and the front of the car rises. The engine may be pulled back a bit, but not to the point of bogging. If the car is set up correctly, the nose will rise evenly and in a controlled fashion. The rear wheels should remain in position under the wheelwells, meaning there's little noticeable squat or separation.
On the other hand, we've all seen some drag cars launch in ugly fashion. The classic example is when a Mustang leaves with a twist--you know, it lifts the left front wheel up high while the right front tire stays on the track. When this occurs, you can bet there's a huge amount of separation between the driver-side rear tire and the wheelwell, and that the passenger-side tire is tucked up in the wheelwell. The car appears to be twisting, or rotating, to the right as it accelerates. This is referred to as "roll rotation." And excessive roll rotation can lead to all sorts of problems. Instead, what we're after is controlled pitch rotation, which in lay terms is called "weight transfer," or more simply, a wheelstand.
In the case where a car roll rotates excessively, as the body rotates to the right, the rear housing rotates under the back of the car in the opposite direction. This is why you'll see separation between the left rear tire and the wheelwell. You may even see the driver-side tire being planted harder into the track than the other tire.
This may look wild--almost cartoonish in some extreme cases--but it wreaks havoc on the rear suspension and the chassis. Because the rear housing twists excessively under the body, it tends to tear up torque boxes and bushings, and it can bind suspension links. It can also cause the shocks to reach full extension and top out--all of which is bad for traction and handling. On the other hand, vehicles that leave straight, go straight down the track. In addition, they are easy, safe, and consistent to drive.
To counter roll rotation, racers may stiffen the right rear spring or install an airbag. These methods work to a degree, but there's a better, more modern way to set up a drag car--and that's by installing a drag race-style rear antiroll bar, such as the one shown here from Wild Rides Race Cars in Farmingdale, New Jersey. The system retails for $299.95, and we decided to ditch the airbag in our NHRA-legal Stang and give it