When you decide to alter your vehicle’s stance, nine out of ten times the geometry changes in a negative way, which then goes on to affect the performance and daily driving abilities of your car. Luckily, the fix is an easy one. Adjustable suspension control arms will allow you to align and setup your car to your desired specs. However, there are many pieces floating around on the market that are poorly made but come at a bargain price, making them hard to resist. Fight the urge and remember that control arms are a critical component on your car and having one fail can spell disaster before you know it.
Fortunately, there are companies out there that are producing very high-grade and quality components at very reasonable prices. SPL Parts is one of those few businesses. Almost all of their parts are built in the USA, not because it’s the American way, but they have total control over the product materials and quality.
SPL Parts offers a slew of suspension components, but we’ll just be focusing on its 350Z pieces. The SPL-fabricated chromoly front upper control arm allows front camber to be adjusted as much as -3.5 degrees, and also allows for +/- 1 degree of caster adjustment. The rear lower/camber link controls rear camber on the Z and allows a whopping +/- 10 degree range of adjustment. The new hybrid adjuster features precise adjustment and motorsports-quality spherical bearings providing less deflection under load for better performance. On the 350Z, the rear mid-link serves two functions: it controls rear toe and it also holds the rear spring. The SPL replacement arm is a CNC-machined aluminum piece that offers full adjustability of both the spring height and rear toe angle. The arm is designed to allow the use of 2.5-inch ID race springs in place of the stock spring, which makes a wide range of spring rates and spring length available for full custom tuning of ride height and stiffness. Another threaded adjuster provides +/- 6 degrees of toe adjustment.
Dialing out front bumpsteer can reap major benefits in lap time, and the SPL outer tie rod end allows front bumpsteer to be adjusted. The rod end pivot point can be moved in 0.25-inch increments from -0.5 to +0.5 inch. Lastly, specially selected materials—heat-treated chromoly pins and super duralumin spacers—are tough enough to withstand the high steering forces from drifting.
»Rear mid-link is constructed from billet 6061 aluminum and has an adjust-able height lower spring perch designed to accept 2.5-inch ID race springs.
»Pro outer tie rods feature adjustable bumpsteer geometry, and the position of the tie rod end pivot point is 5-way adjustable in ¼-inch increments, from -½ to +½ inch.
»Pro rear lower links/camber arms feature 1.125-inch 4130 chromoly tubing that’s kinked to allow the arm to clear the sway bar end links under suspension travel.
»Pro front upper arms feature chromoly tubing with a triangulated frame design for ultimate strength and light weight.
While all of this info sounds great on paper, it means nothing if we install the arms and they are impossible to adjust. We’ll end up with shiny new arms and modified suspension geometry perhaps worse than factory! Thankfully, the bright minds at SPL understand this all too well and have designed each and every component to be adjustable, on the car, without removing a bunch of parts to make changes. Installation of the components is literally as simple as removing the old parts, properly adjusting the spherical rod ends so that they have adequate thread engagement and then bolting the arms back on. In the case of the rear mid-link, SPL has an online, easy-to-use spring calculator that allows you to figure out exactly what length spring you need for a desired ride height range and spring rate, which means it’s just a matter of bolting the arm on with the spring perch at its middle ride height setting and fine-tuning from there.
Perhaps the satisfaction comes when it’s time to align the car. The smooth adjustments and now solid spherical rod ends make even tiny changes in toe and camber show up on the alignment machine instantly and consistently. When you’ve got the car setup just as you’d like it, it’s as easy as tightening the cap screw in the hybrid adjuster; no more worries about toe changes that will occur from tightening a jam nut!
So while it is important to have quality components (as the SPL arms no doubt are—the quality of the fabrication and machining is top notch and they use the best rod ends available), it’s critical that the suspension arms are easily adjustable, and it doesn’t hurt if they look good too. In the grand scheme of things, this ease of adjustment offered by SPL will save you money at the alignment shop, each and every time you align your car. Let’s not forget the peace of mind that comes from knowing you have the best materials available holding the wheels to your car.
In the case of the rear mid-link, SPL has an online, easy-to-use spring calculator that allows you to figure out exactly what length spring you need for a desired ride height range and spring rate, which means it’s just a matter of bolting the arm on with the spring perch at its middle ride height setting and fine-tuning from there.