Project Evo X GSR, Completing the Suspension with Whiteline
It's been a long time between updates on Project Evo X GSR. It hasn't been for lack of trying, the car has been through a couple of different owners and it's been hard to catch up with it. Well we have caught up with it at last and it's time for some long awaited parts to go in.
It's a good thing too, Whiteline has come out with some new parts for the Evo X in the meanwhile. When the project was more active, the only parts available were swaybars but since then they have come out with a roll center and bump steer correction kit, a kit to reduce front lift and add positive caster, an adjustable camber link and a full bushing set.
Now that a full gamut of parts are available it was time to get to work, install and evaluate them.
The stock Evo X anti sway bar diameter is 25mm. The Whiteline bar is 27mm in diameter, which equates to a 36% increase in stiffness just from the increase in diameter. The shape is also stricter which results in another increase. The Whiteline bar is 3 way adjustable and at the stiffest position will result in a further 50% increase in stiffness (part number BMF55Z). The Whiteline bar has the potential to be up to 100% or more stiffer than stock. The Whitline bar sits in hard urethane bushings for a more direct coupling as well compared to the stock soft rubber parts.
The Whiteline rear bar is 27mm in diameter, up from the stock 23mm diameter. This equates to a 90% increase in stiffness due to the diameter change. If you put the bar in the stiffest of the three positions, the increase in stiffness can be about 150% greater than stock (part number BMR84Z). The bar sits in urethane bushings and has clamp on collars to prevent it from moving back and forth in the chassis. We really feel that adjustable bars are important for a car that sees track duty. It is easy for a one person pit crew to adjust the sway bars to tune the car's balance but nearly impossible for one person to change springs to tune the chassis and still see some track time!
The Whiteline camber/toe arm (part number KTA135) replaces the stock lower lateral link and gives a lot more leeway in adjusting both the camber and toe settings. It has sealed spherical bearings instead of soft rubber bushings in the ends so there's no mush that can impact the suspension geometry under load.
The Whiteline Roll Center/Bump Steer kit (part number KCA395) is an important part for a lowered car. When a car is lowered, the roll center or the geometric point in space that the front of the car rolls about drops faster than the car's ride height. This increases the roll couple or the distance between the car's center of gravity and the roll center. This gives lateral forces in cornering a longer lever arm to roll the car over. By lowering the outer pivot point of the lower control arm, the roll center location can be returned to close to the stock position and the roll couple length, kept about the same as stock. Relocating the outer pivot point position can also give a more favorable camber curve by reducing the tendency for the camber to become more positive under roll that lowered McPherson struts can exhibit. The Whiteline roll center correction kit has a ball joint with a longer shank to effectively lower the pivot point with no fabrication.
When lowering the lower control arm lower pivot point the tie rod end must also be lowered or you could develop a large amount of bump steer. The Whiteline kit also has tie rods with longer shanks to lower the tie rods by the correct amount to keep excessive bump steer at bay.
