Project SEMA Scion Tuner Challenge FR-S


The rear shock also has an easy to reach compression damping adjuster.  Like the front, the rear has a stainless steel body and a stiction free stainless and plastic spring seat.  The shock eye has a low compliance bushing.
The KW Clubsports feature dust boots and micro cellular urethane bump stops.  The MCU bump stops provide a progressive increase in rate to reduce harsh bottoming that can upset the chassis balance if it happens while cornering and also serves to reduce shock when large bumps are hit.  As we have said many times before, we feel that KW’s have one of the best combinations of price, performance and long term durability.
Howard Watananbe hangs the KW Clubsport and removes the lower control arm so we can install some bits from Whiteline.  We will be replacing the lower control arm bushings and lower ball joints with some performance enhancing pieces.
For the rear lower control arm bushing, the squishy rubber will be replaced by these Whiteline polyurethane pieces. The bushings use a thick aluminum sleeve with thin low compliance urethane bushings to reduce flex while still absorbing shock and vibration.
The Whiteline front lower control arm bushing is a pretty trick part that serves several functions.  First, is has a lot less flex than stock but is designed to articulate in the directions needed to reduce binding.  Next, it offsets the front of the lower control arm inwards to cant the control arm forward, increasing caster by about 1/2 of a degree.  This increased caster improves straight line stability and steering self return.  The Whiteline bushing also levels out the control arm pivot points to reduce anti dive.  It also increases negative camber when the wheel is turned reducing understeer.  Getting rid of anti dive reduces understeer while trail braking.  The Whiteline bushings are very high quality with steel shells in unsupported areas for a positive press fit.
The ball joints were replaced with these Whiteline long shank units that effectively lower the outboard pivot point.  This helps correct the roll center and camber curve that gets messed up when a car is lowered.  This will help reduce understeer by allowing for more negative camber under roll and will also reduce body roll by moving the roll center closer to the car’s roll axis.  Since moving the ball joints lower alone would increase bumpsteer, the outer tie rods are replaced as well with these parts that move the tie rod pivot lower to keep the relationship to the ball joint pivot the same.  Cool stuff!  It’s all in the details.

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