This is the Xtreme Grip sway...
This is the Xtreme Grip sway bar kit from CorteX Racing. The bar is a standard piece from Speedway Engineering, which is spec’d per application. These arms are built by Speedway Engineering specifically for the CorteX Racing Xtreme Grip suspension, but they are also available in many configurations to fit other suspension designs and can even be custom bent by Speedway per your spec if need be. Variations on this kit are available from CorteX as well.
One thing that we should probably clear up right off the bat is that an antiroll bar—more popularly known as a sway bar—is not the final word in handling, nor is it the most important component; they’re simply a tuning tool that must be tailored to work with the rest of a suspension system to get the desired handling effect. Sway bars do that by adjusting the understeer/oversteer balance of a car as it negotiates a curve by essentially coupling the front wheels together and using torsion to overcome body roll. That coupling also allows fine-tuning of the amount of load that transfers to the outside tires during cornering.
The key word in all of that is tuning. Technically, you can run a car without sway bars and get similar roll resistance by cranking up the spring rate, but you’ll end up with a car that’s extremely stiff and doesn’t handle bumps or irregularities well. Sway bars (either in tandem or singly in the frontend of the car) allow for softer springs, since it’s essentially an auxiliary torsion spring that only comes into play when you need it the most: while cornering.
Sway bars come in two styles: standard one-piece bars, and three-piece splined bars, often referred to colloquially as NASCAR bars. Nearly all factory cars use one-piece bars and soft rubber bushings since they are cheap to manufacture and will create enough roll resistance without sacrificing comfort. Many enthusiasts turn to larger-diameter one-piece bars with polyurethane bushings to increase effectiveness, but there are still some inherent drawbacks like deflection and binding.
While standard one-piece bars...
While standard one-piece bars use rubber or polyurethane mounts, these billet spherical bearing mounts available from CorteX Racing are a big key to the effectiveness of the this kit since they allow the bar to roll easily, but prevent deflection and binding from occurring at the mounting points.
That’s not to say that traditional-style one-piece bars and bushings don’t work well; they absolutely do on many cars, but they introduce variables that are difficult to tune out on serious Pro Touring or track cars. By design, single-piece bars can and do flex along the arms as well as on the torsion spring section of the car, which causes an incalculable reduction in the bar rate of the whole assembly. Larger, stronger bars negate some of this, but the torsion is still not isolated to the torsion spring. The binding and deflection part comes from the use of pliable mounts that squish since they absorb energy rather than forcing the bar to handle all of it. That can result in unpredictable winding and unwinding of the sway bar when under extreme loads.
The three-piece splined sway bar effectively eliminates both problems since it typically uses spherical bushings or bearings at the end of the torsion bar that eliminates deflection and binding. The splined arms are also much more rigid than the one-piece bar’s arms, so the torsional force from the suspension is focused upon the torsion spring itself.
Here’s how the arms and the...
Here’s how the arms and the bar interact on a splined sway bar. Once the arms are tightened onto the bar there will be no movement at this joint, so all torsional forces will be exerted on the bar itself.
As for the tuning aspect, because of their extensive use in motorsports, splined bars are available in a large selection of bar sizes and rates, plus they’re easy to swap in and out, giving you the ability to tune your car quickly for a specific activity. One-piece bars are usually only available in one or two diameters and are platform-specific rather than universal, so you’re limited to what’s available on the market. For quite a few offbeat classics, there may not be anything available.
The good news is that with a little planning and the correct parts choice, you can upgrade to a splined sway bar on any car; all you really need is a flat surface to locate the mounts, the tabs on the lower control arms for the endlinks, and arms with the proper bends to clear steering and other components.
With all that said, do you actually need one? Maybe. It depends on how hard you like to drive your car and how much control you want over making adjustments. For the Max Effort ’67 Cougar project car, the tunability of the suspension is vital, so we’ll be installing a splined sway bar from CorteX Racing.
When it comes to locating...
When it comes to locating the mounting points for the sway bar mounts, the ideal spot is a flat area on the frame forward of the control arms, which may require a small amount of fabrication on some cars. Exactly where the mounts are located will dictate not only the length of the arms needed, but also the diameter and rate of the bar required. Make sure to account for clearance on the arms as well.
To create the mounting points...
To create the mounting points on our ’67 Cougar, Ryan Kertz of Kertz Fabrication cuts two stripes of sheetmetal at 9x2 inches.
Back under the Max Effort...
Back under the Max Effort Cougar, Kertz uses a small template to outline the area where the nuts will need to pass through the frame.
Kertz used a Miller Extreme...
Kertz used a Miller Extreme 375 plasma cutter to make quick and clean work of the holes, but a drill and a carbide burr can also get the job done. Just remember to account for the size of the weld since the plate needs to sit flush to the frame.
Once the plate fits flush,...
Once the plate fits flush, it needs to be welded in completely around the perimeter.
The spherical bearing in the...
The spherical bearing in the mounts are intended to be quite snug, so sliding them onto the bar will likely require a little persuasion from a dead blow hammer. The mounts should be equally spaced from the end of the bar. Double-check against the plates on the car as you go.
Once the mounts are installed...
Once the mounts are installed on the bar in their final position it can be bolted into place, and these collars are installed to lock the bar in the inboard side of the mounts. The collars prevent any unwanted side-to-side sliding of the bar in the mounts.
With the bar locked into place,...
With the bar locked into place, the sway bar arms can be bolted on and double-checked for clearance through the suspension’s range of travel.
For mounting the sway bar...
For mounting the sway bar arms to the lower control arms, all that is needed are simple tabs like these. The endlink itself is a pair of rod ends that will allow movement through the range of travel without binding or deflection. Note the multiple mounting holes for the endlink on the sway bar arm; these effectively shorten or lengthen the arm to aid in suspension tuning.
Here’s the full kit installed...
Here’s the full kit installed on the Max Effort Cougar. Between the tunability of the sway bar and the coilovers, we should have all the options we need to dial in Max’s performance once it’s out on track.
This install was actually...
This install was actually the end of an extended stay for our Cougar at Infineon Raceway in the capable hands of Filip Trojanek of CorteX Racing and Ryan Kertz of Kertz Fabrication. With their help we’ve mostly wrapped up the chassis and suspension work, so it’s time to move on. We owe these two a great deal of gratitude for their hard work and knowledge. There is still a lot of work to do, but it’s definitely got the stance and attitude!