Drift Car Suspension
Perhaps the most important modification to any drift car is suspension. Competitive drift cars use an integrated coil-over strut combination. A suspension system has many variables - adjustable caster and camber angle, toe-in and toe-out angle, adjustable compression and rebound damper, adjustable ride height, and variable anti-roll bar (sway bar) stiffness. A suspension set-up that allows for these variables is ideal for drifting; since a driver can fully customize the way their suspension feels and reacts to their specific drift car and track conditions.
The purpose of caster angle is basically to allow the front wheels to self-center while under the stress of cornering. Too much caster and you can get what is known as wheel shimmy. This is when the front wheels flick side-to-side rapidly reducing tire to surface grip. Too little caster and the car will oversteer. Caster angle is adjusted by sliding the front wishbones on the hinge pins. To increase caster, slide the top wishbone back or the bottom one forward or a bit of both, do the opposite to reduce caster angle. It is very difficult to measure caster angle so it is more a case of trial and error to get the correct setting. The best starting point would be both wishbones in the center of the hinge pins as there is positive caster built into the steering hubs naturally.
Camber angle is the angle of the wheel when viewed from the front or rear of the car. There are three possible angles, positive camber, neutral camber and negative camber. If the top of the wheel leans into the center of the car you have negative camber. If the wheel is vertical you have neutral or no camber and if the wheel leans out you have positive camber.
One suspension tuning method for drifting still popular in Japan is known as Demon Camber or “Oni-kamu,” in Japanese. It involves setting the suspension with extreme negative camber in the front to reduce front tire slide and improve grip. Negative camber on the rear will create understeer, making the car more difficult to control during a drift.
When viewing a car from above, Toe is the angle at which the tires tilt into or away from the center of the chassis. Generally, on a rear wheel drive car the front wheels will have neutral toe or toe-out. A few degrees of toe-out on the rear wheels, in some vehicles, can make setting up a drift a little easier. With the correct toe angle on the front and rear you will have a stable car that has good traction through the corners.
Shortening or lengthening the steering links or tie rods adjusts toe angle. Shorten the links – more toe-out, lengthen the links – less toe-out. There are different methods to adjust the rear toe angle depending on which make and model of car you drive, almost all adjust the rear lower wishbone to give desired angle.
Higher end drift suspension systems will let you separately adjust the compression and rebound damper rates of the strut to further customize your suspension setup and feel.
Almost all modern cars use the MacPherson strut suspension system. This type of suspension allows the ride height to be adjusted independently of the suspension travel. There is no perfect height setting or spring/strut combo for any car but many suspension manufacturers offer suspension tuned packages specific to certain car models for drifting.
Ride height is adjusted on the collars of the shocks, screwing them down increases the ride height while the opposite is true when lowering the car. Set the rear end a couple of millimeters higher than the front. In general, you want to run the car as low to the ground as possible without scraping the chassis on the ground. A lower center of gravity will increase stability and help reduce body roll while drifting.
Anti-roll bars, or anti-sway bars, provide a link between the left and right side suspension and keep the suspension at nearly the same level vertically when under extreme weight transfer conditions as when drifting; thus, decreasing body roll and increasing stability.
Sway bars should be chosen to match your springs. If you are planning on installing stiff springs for drifting, there is no need for a large diameter sway bar. The combination of stiff springs and small sway bars is enough to control body roll. However, large diameter sway bars are necessary if you will be using relatively soft springs. This is a popular configuration for daily drivers since the ride is not as harsh but this is not necessarily the best setup for drifting.
Soft springs with large sway bars and stiff springs with small sway bars accomplish virtually the same goal of providing a stable suspension while reducing excessive weight transfer. However, a stiff spring/small sway bar setup is generally better than a soft spring/large sway bar setup because stiff springs reduce front-to-back weight transfer. With soft springs, side-to-side weight transfer is controlled by the sway bars, but there is a fair amount of uncontrolled front-to-back weight transfer due to the soft springs. In other words, using soft springs can result in brake dive and acceleration squat which are detrimental to overall drift handling.
Here are some general rules when using adjustable sway bars:
• Wet track = disconnect or soften as much as possible.
• Damp or slippery track = soft as possible
• Grippy dry track = stiff as possible.
Bushings can also be upgraded with urethane parts to help further stiffen the chassis and reduce body roll. Most Nissan vehicles have a floating rear subframe which is usually fixed in position with billet aluminum or urethane “drift pineapples” to prevent the frame from moving during drift.
Overall, suspension in a drift car is stiff with high damper rates, sway bars are upgraded to reduce body roll and caster is often increased to improve the car’s stability during a drift. All of these suspension modifications are done to keep the tires where they belong during a drift - on the road.