The Fabulous Flog: A Look Inside Dai Yoshihara’s Falken Tire Subaru BRZ


A view of the radical shock mounts from below shows the large offset in them.  Instead of being used to adjust camber, the camber plates are instead used to adjust kingpin inclination and scrub radius.  Having these adjustable is useful in a drift car because they affect turn in and self steer. 
The camber is grossly adjusted using these pills on the lower strut mount.  Camber is then fine tuned on the lower control arm. 
One of the pains to modify the FR-S/BR-Z for drifting is that it has awful steering geometry for high steering angles from the factory.  The challenge has been to get good steering geometry while staying within the Formula D rules which do not allow for modification of the front crossmember.  The ideal steering rack location is within the crossmember itself and the rules will not allow the radical modification of the crossmemeber needed to put the rack in the right place.  Because of this, getting the best compromise of geometry for the steering has been the center of the car's development. The team knew this was going to be an issue going in and designed a lot of adjustability into the system. The Falken BRZ does away with the stock hardware entirely using this custom CNC billet upright and separate knuckle assembly.  Custom fabricated control arms are used as well.  The front suspension is adjustable and corrected for roll center, camber curve, anti dive and bump steer.  Ackerman is also adjustable via interchangeable knuckle pieces. 
The result is an impressive 68 degrees of steering angle.   There is so much angle that the front track had to be greatly increased to make room for the tires considering the wide displacement of the frame rails needed by the stock boxer engine.   A side effect of the wide front track is less understeer. The control arms are designed to be safety valves of a sort, they will bend before the chassis does limiting damage to the rest of the car and making repairs quicker and easier. 
Fine adjustment of camber is made at the outboard spherical bearing while caster is adjusted at the control arm's rear inner bearing.  Anti dive is set at zero via the front lower control arm bearing.  This makes left foot braking more predictable. 
The front sway bar is a custom 3 way adjustable part made for the team by Progress Automotive.  It is mounted inboard to allow for tire clearance which increases the bar's leverage ratio but has short arms to regain some stiffness.  Due to the wide front track limiting weight transfer, it was found that the front sway bar didn't need to be too stiff. 

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