The subject of coilovers, especially ones offering both ride-height and damping-force adjustments, covers a lot of turf. Coilovers give users the option to improve and customize their car, but can also sour the handling if poorly adjusted. Often, after installing a set of coilovers, the impressionable types will lower their car past the height for which the geometry is designed.
Though it might get plenty of attention, dropping the car to the point roll centers are subterranean and contact patches are halved doesn’t help the road-holding at all. The misinformation out there on coilovers often leaves the beginning driver chasing their tail, banging their wrenches off the wall, and wishing they’d stuck with the stock suspension. Without the experience and time to get them properly adjusted, coilovers can introduce more complex problems for a beginner.
Response, and a lowered center of gravity, are just two things a well-sorted coilover provides. But it’s important to remember; it still needs to cushion the car over bumps and facilitate the right rate of weight transfer. Essentially, the function of a shock is to improve the contact patch and control body movement. Though there’s often a tradeoff between the two, they aren’t mutually exclusive. As we’re starting to see, there are quite a few things to bear in mind when delving deeper into shock functionality. Fortunately, we found some of the best in the business to guide us on our way.
Picking a Path
To get a better sense of some of the mistakes entry-level drivers should avoid, I spoke with KONI’s Lee Grimes. Eloquent, technically savvy, and affable, he was happy to go in-depth with this complex subject while keeping everything completely digestible. He has a way with clear explanations, so he started his lecture with a few general thoughts on suspension tuning to establish a foundation.
“First, you’ve got to ask: ‘What’s the long-term plan with this car?’ Daily driver, weekend-only toy, dedicated track car, show car, or a mix? Once you’ve considered how much you’re willing to compromise, you’ll have a better sense of what products are appropriate,” he begins.
When the driver is only interested in a handful of track days in an otherwise daily driver, a set of replacement non-adjustable shocks should be the ticket. They will work better than the OEM items; their damping is better-suited for performance driving. Plus, since car manufacturers are known to save money on things that aren’t visible to the naked eye, it’s fair to assume that a modestly priced set of performance shocks will make a significant difference — enough to introduce the avid amateur to a level of crispness they’re not familiar with seeing.
Allen Briere, another one of KONI’s bright racers, elaborated on the issue. “For most beginners, they really just need to focus on ride height, which can be done with a simple strut and spring combination. Their driving level isn’t high enough yet to appreciate and tune what the car’s doing, so a coilover would only confuse them,” he says.
These non-adjustable shocks quickly become limiting for the more experienced driver who is ready to refine the car’s handling and responses. Unable to provide adequate chassis and suspension tuning, the non-adjustable shocks limit the more demanding drivers. “Depending on how far someone wants to go, it’s important to give enough room to keep developing. For instance, the KONI Sport adjustable damper will allow them room to grow,” Briere recommends.
Seeing Through the Fog
To many, shock tuning is something elusive and vague. “Some may act like shock tuning is magic — like pixie dust,” Grimes chuckles. “In reality, it isn’t that hard. If you want to tune a shock, start by moving in small increments. If it gets better but not totally satisfactory, try a bigger change. If the change felt like too much, try less. If a big change still doesn’t really make a difference, you know you have a problem a little further upstream.” Obviously, there’s a bit more to it, but that sensible approach ought to help the initiate give it a try themselves.
In Grimes’ mind, tuning the damping should come after significant chassis changes like altering spring rates and making sure the car has suitable bushings. In other words, damping is a fine-adjustment that ought to be done once the more significant steps have been taken. “I’m a firm believer in strengthening the weakest link in the chain, so adding a set of $2,000 coilovers isn’t smart if the rest of the car isn’t tight and up to the task.” Grimes states.
This homespun advice might not convince the readers that adjusting the suspension is within their abilities. So, in the hopes of getting the skeptical and worrisome to take the next step, here are some more technical suggestions.
Rebound and Compression
There are a few reasons the semi-adjustable suspension becomes appealing for the intermediate driver. For instance, more rebound is needed to complement the spring rate. As you increase the spring rate, you need to increase rebound damping to suit. In fact, in a mildly modified car, most of the body control is done with rebound damping.
“Rebound damping controls the sprung weight, and it also controls spring and chassis oscillation,” Grimes starts. “It can help fine-tune understeer or oversteer. For example, by adding more rear rebound firmness, the car will rotate more going into the corner. This is ideal for a front-wheel-drive car, which inherently understeers.”
In the case of a car with a powerful engine driving the rear wheels, the rear rebound control is still responsible for initial turn-in. More rebound firmness means better turn-in, but beyond a point, it begins costing the car in traction. To keep the tire firmly on the surface of the road, we need a little more compliance, and so we back off in rebound stiffness to find that ideal balance.
If the car is a dedicated racing machine, or if you’re searching for the last few fractions-of-a-second in lap times, the other feature you may want to control with your new suspension setup is compression damping. “Compression’s duty is to control the unsprung weight and hold the tire to the ground. This allows the user to adapt to surface variables like concrete, asphalt, bumps, and berms. While adding more compression-force doesn’t exactly do the same as adding more spring rate, it can band-aid some handling deficiencies of under-sprung cars,” Grimes adds.
“At the end of the day, compression damping maximizes the grip potential between the surface of the road and the tire,” Grimes elaborates. “When there’s more grip available, as is the case with sticky tires and/or a sticky track, the car and lap times will benefit from more compression damping.”
Horses for Courses
Of course, these terms are all relative. Different cars have suspension designs of differing quality and intricacy; what works on one car, might not work on another. Some cars benefit from a slightly softer setup. “In general, you want the chassis and suspension to do as much work as possible with maximized grip,” Grimes begins. “But in the case of a BMW, a car with supple and communicative suspension, you really want to allow the chassis to move a bit for the best control. In this case, too much stiffness is going to worsen your handling,” Grimes advises.
“On the other hand, a Dodge Neon was not designed with much suspension movement in the front, to begin with. As a result, a lowered Neon may bounce on the bump stops. It may work to stiffen the car to ‘lockdown’ the front, minimize any unnecessary movement, and optimize grip,” he asserts. While it is a crude solution, some simple suspension setups like the Neon’s leaves the user with few options. It’s all about maximizing what’s at your disposal.
Avoiding Trackside Migraines
Theory and specific advice are all well and good, but there are practical tips to bear in mind when setting a shock to work well on the track. Below are several suggestions to help minimize headaches and make the most of the time spent in the pits.
• The silly but altogether-too-common mistake of adjusting the shocks incorrectly. Whether tuning rebound or compression damping, make sure you’re turning it in the right direction.
• Remember that all suspension parts interact with others; they don’t exist in a void. Every change to one specific part may affect another part of the system.
• Determine the cause of bottoming — is it due to shock length, ride height, bump rubbers, and/or spring rate?
• Suspension bind can make a car react in odd or unexpected ways. Determine the cause of binding — is it due to side-loading, camber-plate issues, bushings, or springs?
• While copying the setup of a similar car might work, it’s always better to try and refine the configuration to suit your driving style. All vehicles and drivers are different.
• Be careful not to cross-apply information from one discipline to another. What works on the autocross, won’t be as useful on a fast road course. Cars with aerodynamic upgrades such as wings and splitters will have different suspension needs than non-aero cars.
• Make sure to match the shocks to car usage, driver preference, and other mods; not just the spring rates alone. While achieving a single fast lap is excellent, finding the right balance to suit the driver’s style is what typically results in repeatable, fast laps.
The Most Important Adjustment
“One of the most common complaints I hear is ‘my car isn’t ready yet.’ There’s plenty of misinformation going around on the internet which suggests that someone can’t have fun with the car until there are go-fast parts on it. To get started, all you truly need are good shocks, good brakes, and good tires,” Briere adds.
But to get the most from those parts, seat time is necessary. It takes an abundance of experience behind the wheel to precisely understand what the car is doing when speeds are high and runoff space is limited. Over time, a sensitive driver flirts with the limit and gets a sense of what it takes to drive up to the edge, gets a clearer picture of what the car needs, and then makes the right adjustments. To have the wherewithal to address handling issues while driving consistently quick laps is something that no grasp of theory (no matter how strong) will provide.
For more help on properly setting up your car for whatever discipline you are running, KONI has some excellent tips and tricks on its North American website. I often refer to the road course adjustment procedures when I get stuck trying to figure out which way to adjust for a difficult corner.
“For the beginning driver, the greatest gains are made between the driver’s ears — fortunately, that’s where their smile is located,” Grimes waxes poetic. As a driver grows more comfortable at the ragged edge of adhesion, playing with the suspension settings in a reasoned and disciplined way comes into play. If done correctly, it becomes a hugely valuable tool that separates the quick from the blindingly fast.