Suspension 201: High-Performance Coilovers

BOOKS HAVE BEEN WRITTEN ILLUSTRATING THE MATH, SCIENCE and design of suspension systems. In the case of coil-over suspension systems, buyers must consider price, application, construction and adjustment capabilities when selecting the best coil-over system for their vehicle. If the objective is to simply achieve a decent ride on a lowered stance, there are a number of options. The quality of the product will determine if it lasts for 10,000 miles or 200,000. If the objective is to tune a vehicle for maximum performance on the street or on the track, a higher investment will be required.

Staff Report

DSPORT Issue #150


Price, Application & Adjustment

Coil-over suspension prices vary as much as the available configurations. Just like anything else, the most expensive system does not guarantee the best performance for every application. There are suspension systems available for applications ranging from show to competition. That being said, the most expensive and capable system may not be the logical choice for everyone. The big-dollar systems may feature degrees of adjustability that will never be utilized. It can be sheer overkill. It’s like using a flamethrower to light a candle. Of course, it will get the job done, but it may also put an unnecessary strain on your bank account. For the people driving everyday on the street and tracking on the weekends, a high- quality, entry-level coilovers is a great starting point. With a purpose-built racecar, you’ll be forking out the money for an independently adjustable 2-, 3- or 4-way damper system. These dampers feature additional adjustability that will allow the driver to squeeze every fraction of a second out of a track.

Adjustable SuspensionBy first determining the goals of your performance suspension, you’ll be better equipped to select a set of coilovers that will meet your needs and budget.

Top Down Design

The hat or the top portion of a coilover is a good place to start looking when considering a coil-over system. Many systems include a camber plate and pillow- mount designed to replace the factory hat. The pillow-mount provides a more rigid interface between the suspension and the frame. The benefit is greater predictability and more direct feedback from the suspension to the driver. The drawback on a pillowball mount can be increased noise, vibration and harshness. Coilovers featuring adjustable camber plates allow for adjustment of the camber angle. This can be useful on vehicles that are significantly dropped or used for road racing.

Pillow-mountsAs with any spherical bearing, pillow-mounts are designed primarily for race applications and wear out over time. Replacement of pillow balls can usually be performed by the manufacturer or a performance shop with a quality aftermarket bearing.

Springs ‘N’ Things

Eibach springs being manufacturedFurther down the coilover assembly is none other than the coil spring. As mentioned before, the coil is designed to hold the weight of the car. The coil is also responsible for keeping the tire firmly planted on the ground through bumps and changes in the road. This means that it will compress over bumps and then expand over holes. The problem with a loaded spring is that once compressed or decompressed it will recoil with just a bit less energy than was put into it. Without a dampener coupled to the spring, the cycle would oscillate at the spring resonance until it eventually comes to a stop. This effect would be detrimental to the performance of any vehicle and results in a rather uncontrollable ride. This is why the matching of the damper to the spring is so critical. In theory, the coilover manufacturer should be delivering a spring and damper system that is matched to work well together when placed on the intended vehicle.

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