The trickiest part of making a car both track- and street-worthy is the suspension. This is the double-edged sword because you want something soft enough to be comfortable and offer sufficient suspension travel on the street, while being stiff enough to handle all the loads generated on the track. We want to be competitive with a dual-purpose car, so we're going all out with Project Z's new suspension. Although the Nismo S-tune suspension the car came on was quite good on the street, it won't give us the competitive edge needed at the track because the spring rates are just too soft to support loads from such a heavy car and the grip generated by the Nitto NT05 tires we've mounted.
Instead of trying to get our suspension to simultaneously fill both needs, we decided to go with a different strategy. Just like real race cars, we'll be using different spring rates to adjust for differing grip conditions. This way, we'll have a set of race springs and a set of street springs that we will swap out between track weekends and our daily commute. With that in mind, we'll be using a coilover suspension setup to make spring swaps a little easier.
Moton's Clubsport external reservoir monotube coilover kit was designed for the serious cl
There's a problem with our strategy, though. Because of the drastic difference between springs rates used on the street and on the track, we needed a damper that can provide the right amount of damping in both configurations. In most cases, off-the-shelf coilovers are designed and calibrated (in terms of damping force and stoke length) for use with the springs that it came with. Some adjustable dampers can be fine-tuned to use slightly stiffer or softer springs, but not huge increases in spring rate like what we have in mind.
To fit our dual-purpose needs, we looked at some top-end, race-quality coilovers designed for use with multiple spring rates. Race teams change springs on their race cars from track to track, so race dampers/coilovers typically don't come with springs. It's left up to the discretion of the end user to determine the spring rate and spring length needed. And because of this, race-quality dampers often have a much larger range of damping force adjustment so that the dampers can be tuned to match the spring rate used.
While most street tuners are more familiar with brands like TEIN, KW, Koni or even the more rare JDM brands, those in the world of racing will know the name Moton. Manufactured in the Netherlands, Moton is synonymous with true racing suspension. The company's products were on 30 percent of the starting grid at Le Mans in 2000 and had since become very competitive in most forms of professional sports car racing all over the world. Moton's newest product, the Clubsport, is designed for the serious club racer at an affordable price.
Eibach Springs supplied the two sets of 2.5-inch-diameter street- and race-rate springs. W
Since our Z is by no means a race car in terms of weight, grip, aerodynamics and suspension travel, the Clubsport would be the perfect fit for us. The Moton Clubsports use an external reservoir monotube damper with independently adjustable compression and rebound damping, unlike more expensive race variants that have high- and low-speed adjustability for both compression and rebound. Internally, the Clubsport construction is similar with top-end race variants using high-quality aluminum for the damper body and an extremely large 22mm piston rod. This means the Clubsports are extremely light and provide finer damping control because the larger piston rod displaces 300 percent more damping fluid for the same motion than normal. Unfortunately, we needed to find springs and upper mounts for the Clubsports because they're made for racers-a minor trade-off for superior suspension.
By Jay Chen
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