Suspension tuning the smart way
We often see people go into a new project thinking they'd just lower it, before Scope Creep means they're adding all-new coilovers, mad wheels and tyres, big brakes, and all sorts of other mods. But is this the smart way to modify a car? In the latest video on Marty's STi (check it out HERE) and MOOG's BRZ (check it out and get your nose disrespected HERE) the lads answer this question by looking at some oft-forgotten parts of a car's suspension system: swaybars!
Since bolt-in coilover suspension struts have become cheap and easily purchased, and they allow ride height to be easily adjusted, they have become the go-to modification when enthusiasts look to upgrade the handling of their car. While stiffer springs and shocks make most cars feel faster (due to the inaccurate calibration of most bum-dynos), the reality is you can upgrade other parts of the car first before risking the comfortable ride quality of a stock car.
You may think that stiff springs and shocks help hold your car flat in turns, but it is actually sway bars. As a car goes through a corner energy in the suspension increases in the form of twisting forces, which the sway bars help resist (holding the car flat) and dissipate.
Sway bars, also known as anti-roll bars, are steel torsion springs which attach to the chassis of a car as well as the suspension arms on each side via bushed end links. Different diameter bars can be used to increase or decrease chassis stiffness, with thicker bars adding stiffness and smaller bars decreasing it. Upgrading the strength of end-links and the bushes (which fix the bar to the chassis) also help resist twisting through the chassis under cornering.
Changing the stiffness (by diameter) of sway bars at each end of the car can also help tune the handling of a car by changing the roll stiffness setting in the front and back. Throwing a fat front sway bar on your car with a small rear bar can increase understeer tendancies, while doing the opposite modification can increase a car's tendancy to oversteer. Understanding how these changes affect a chassis can help drivers tune certain characteristics out of their car's handling, by reducing understeer or taming an oversteer-prone set-up.
We all love to tune and modify our cars but it is important to look at different parts of our cars as systems - making one change to one part isn't often the smartest way to spend your money, when cheaper mods could have much bigger benefits.
If you're looking for a way to get your car carving corners nice and flat, enjoying more controllable and predictable handling, have a look at sway bar tuning before you hit up the eBay coilovers as the first step.