The suspension is one of the first aspects of a car that enthusiasts dive into when improving a car’s performance. More often than not, we don’t modify our cars on our own; we choose parts and create a plan based on many outside influences. Vehicles similar to ours and internet ads claiming huge performance gains from certain parts all compete for our attention and promise to turn our cars into unstoppable track monsters.
But does this overwhelming amount of information help us create suspension setups that meet our specific goals? Some issues are easy to spot, and some hide themselves well. Here are some of the common suspension mistakes that may be holding you back.
Sway Bar Bind
One of the least expensive and most impactful suspension modifications involves replacing the anemic factory sway bars with thicker alternatives. It makes the car feel tighter and reduces body roll significantly. Dynamic camber is also reduced, allowing for a fuller contact patch through the corners.
Seems like a great bang for the buck, but there’s an issue. Aftermarket sway bars typically come with polyurethane bushings to make things as slop-free as possible, but they eventually wear out. To fight this, manufacturers often fit bushings that are too tight initially, causing the bar to bind.
The solution? Grease the bushings periodically, or shave off a small amount of the flat portion of the bushing to improve clearances.
Real race cars have a low, aggressive stance, so that must mean that lowering your car substantially is good for your car’s performance as well, right? While a lower center of gravity is great for reducing weight transfer and body roll, it is possible to have too much of a good thing.
Lowering your car too far can result in bottoming out the suspension, and it often goes unknown to the driver. Cornering or driving aggressively while riding the bumpstops of your suspension can lead to all sorts of unpredictable handling characteristics.
To check if your car is bottoming out, remove the springs from your suspension with the car jacked up, and compress the shock through its full range of motion. Your bumpstops should make contact just before metal-on-metal contact happens within your suspension components. Put everything back together and place a zip-tie around the shock shafts so you can easily track how far your suspension moves while driving.
Another, lesser-known side-effect of lowering a car, bumpsteer happens when a car is lowered outside of the manufacturer’s intended suspension travel area which often results in adverse handling characteristics due to the suspension’s geometry at a given ride-height.
Toe can change dramatically with just minor up and down movement of the suspension, and even body roll can affect the car’s toe, making the vehicle unpredictable through corners.
If you’re using adjustable coil-over suspension, you can find the limits where the car begins to bumpsteer with an alignment rack and a little bit of time. Take measurements of the car’s toe as you raise and lower the suspension in half-inch increments. With these measurements, you can find out what the suspension is doing at the extremes of your ride-height.
A well-tuned suspension setup is one of the best ways to maximize grip and minimize lap times. Come see if your driving skills and car have what it takes with one of our HPDE classes or our track day events. Contact PBOC today at (407) 804-0892 with any questions!