The Auto Garage- Tips and Advice: Performance 101: Suspension/Traction Continued
by Eric Bonneman
FeedTheVillage.com - Tips and Advice: Performance 101: Suspension/Traction
The 4” drop, in general, will lay you on the ground and create tire rub in the fender well. The 1” drop will generally not be enough to lower your CG to cause the effect we are looking for. This leaves he 2”-3” drop window at your optimum level. I personally have a 2 ¼” drop on my car. Performance spring rates will vary. You can have solidly stiff springs, progressive rate springs, and soft ride. Solidly stiff springs will give you the least amount of lateral weight being thrown during cornering, but will create the least comfortable ride in general. Progressive rate springs get stiffer as the weight is thrown to it. These are still very stiff, but have some give. Soft ride lower springs will lower your CG (which is good), but they will still leave you with an amount of body roll. Again, I chose right up the middle with progressive rate. Part two of your first step, is anti sway bars. If your vehicle is equipped or not equipped with them, an upgrade here is essential as well. This is necessary for all the same reasons as the spring upgrade. Remember the factory sway bar set up was designed to act for the factory suspension characteristics. When changing one characteristic, we must compensate the rest of the system. Many vehicles have performance sway bar kits available, these will all perform well. You want to use the same rule as the springs when deciding stiffness (if this is even an option on your application). If you feel that your factory sways are sufficient, then you at least want to upgrade the sway bar bushings and end links to polyurethane. This creates a slightly stiffer, progressive, sway bar action over stock. These are also good to add to your after market sways for the same reason. Another option aside from standard springs is coil over suspension components. These include the strut and the spring. These are the stiffest systems you will find. I consider these race components. The best thing about coil over suspension systems is that they are height adjustable. You can literally change ride height as often and for whatever reason you want. These may be good for the weekend auto crosser. You can lay your car to just a breathe above the ground at the track (the lowest CG possible) for the event, and then raise it back up for the rest of the week. These systems cost thousands of dollars, and are for the hardcore. Once your car is lower, the next thing to consider is your camber adjustment. Your camber will change when the car is lowered drastically. Usually to a very negative camber. Again, this is great for a track car, but on the road with a daily driver, you will eat through tires often. Most cars do not have adjustable camber. To combat this you will need to purchase eccentric camber bolts for your lower strut mounts, or adjustable pillow ball mounts for your upper strut mounts. Then you can have your car aligned to back within factory spec. I personally chose a mild negative camber for my car, -1.2 degrees, this is just outside of factory spec, but performs well for me. My tire are showing near even wear as well. Another step in the elimination of lateral movement is wider low profile tires. Wider tires can result in the need for rims to support them, but will offer another drastic increase in cornering, as well as launch traction. But the reason behind the low profile tire is to eliminate side wall flex. This is yet another area that will move the vehicles weight off to the side while cornering. As with the rest of these modifications, you will lose some ride comfort with the extra stiffness.
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