DSPORT MAGAZINE HITS THE NEWS STANDS TODAY
September 1, 2009 News, Uncategorized
Transformation
By Richard Fong
Photos by Michael Ferrara
Drifting was probably the farthest thought from the minds of engineers at Subaru. Known for its championship winning heritage in the World Rally Championship (WRC), very few would have chosen the STi as a tire-smoking, tarmac-sliding competitor. But Eddie Kim at Dynamic Autosports (DA) thought otherwise. After forming a new partnership with Irish driver Eric O’Sullivan and his sponsors at Rockstar Energy Drink, Eddie and the Dynamic Autosports/Gruppe-S crew embarked on building America’s best rear-wheel-drive Sti drift machine.
Full preview after the jump…
By random coincidence, Eddie came across the APR Performance STi that was on the cover car of the December 2007 (#60) issue of DSPORT. Originally built as a demo car and occasional track car, APR retired its 2004 STi from the show scene. Needing a starting point, Eddie acquired this STi and the rest is history.
Chassis Prep
Once the STi chassis arrived, the team went straight to work. The chassis was completely stripped down in preparation for the extensive fabrication work needed. Since Subaru designed each differential (front and rear) to handle approximately 50-percent of the load, the factory rear differential would not have the power-handling capabilities needed to deal with 100-percent of the power. A stronger rearend was needed so the factory differential carrier was cut from the rear subframe. In its place, a Nissan Silvia subframe and R200 differential carrier was welded. Once in place, the R200 differential was connected to the custom 5×114.3 hubs with Drive Shaft Shop (DSS) custom axles. To add the strength, durability and rigidity necessary for grueling drift battles, reinforcement bars joining the rear subframe to the front of the chassis were welded into place. The chassis also received an eight-point Formula D-spec cage for added safety and increased chassis rigidity.
Stop, Drop and Roll
With the chassis and driveline sorted, the build team would focus on the suspension. KW Suspension Variant 3 coilovers were chosen to suspend the chassis and plant the tires to the ground. The coilovers height adjustability allows for corner balancing which optimizes vehicle balance and control dynamics. Gruppe-S fabricators also designed a set of custom sway bar mounts to maximize the efficiency of the Hotchkis adjustable sway bars at both the front and the rear. The thicker Hotchkis bars improve steering response and add greater control of the chassis to the driver.
Up front, subframe spacers were used to adjust the roll center and combat bump steer. The steering knuckles have pickup points that have been adjusted to also minimize the effects of bump steer, giving maximum control and feedback to the driver.
Since APR had already equipped the STi with bigger brakes, a capable system was already in place for the STi’s new drifting duties. In the front, the Project Mu four-piston calipers put the squeeze on Performance Friction Corp’s (PFC) 97 brake pads and 330mm Project Mu brake rotors. PFC states that its 97 compound is a medium torque pad with a flat torque curve. The flat torque curve makes this pad versatile and predictable with excellent modulation characteristics (essential traits for drifting). The factory rear Brembo two-piston calipers were complemented with a set of Project Mu rotors and PFC 97 pads as well. A custom hydraulic hand brake helps to initiate drift with improved response and durability over the factory cable hand brake.
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