Regulation, Multiplication and Application of Torque
[pullquote]THE 1.5 LSD PROVIDES THE POSITIVE LOCK ON ACCELERATION AND THE GRIP-INDUCING TRACTION ON DECELERATION WHICH SUITS TANNER’S DRIVING STYLE. [/pullquote] With the engine making the power and torque needed at the flywheel, a strategy to regulate, multiply and apply this energy was in order. A custom clutch by ACT modulates and transfers the engine’s torque to the G-Force GSR transmission. This G-Force box was chosen for its proven design and ease of repair and maintenance. The G-Force GSR 4-speed sequential transmission features dog engagement and straight-cut gears. The dog engagement enables the driver to make clutchless shifts and eliminates the weak link inherent in synchros. While noticeably louder, the straight-cut gears prove tougher than their helical-cut relatives. While the exact gear ratios are secret, the 4.27:1 final drive is a good indication of the magnitude of the multiplied torque being applied to the OS Giken Super Lock 1.5-way limited-slip differential (LSD).
Although many drift drivers prefer 2.0-way LSD’s to ensure the power is split evenly while accelerating and engine braking (decelerating), a 1.5-way LSD was chosen because of its off-throttle characteristics. According to Steph, “the 1.5-way LSD provides the positive lock on acceleration and the grip-inducing traction on deceleration which suits Tanner’s driving style.”
This LSD splits the power between the custom-offset Motegi Tracklite wheels mounted with Hankook R-S3 rubber. The R-S3 285/35R18 tires provide the contact patch while Tokico HTS shocks with Eibach springs keep the tires planted. The working relationship with Tokico as a development partner provided the team customized valving for the HTS shock absorbers. With the tC’s ability to charge to triple-digit speeds in an instant, improved braking capabilities were a must. The team decided a total of 36 pistons would be necessary to reel in this tC’s speed. A set of Wilwood six-piston calipers squeeze the pads on the front rotors, while two pairs of Wilwood six-piston calipers work the rear. The redundant pair of six-piston calipers are activated by the hand brake to initiate a drift when a clutch-kick is not in order.
An additional pair of six-piston Wilwood calipers help to initiate the drift. The Supra rear subframe assembly made the rear-wheel drive conversion less daunting.
High-Steppin’ Scion
Moving on to the functional aesthetics, Scion Racing bestowed its custom wide-body kit on the tC. The wide fenders allow for wider, more aggressively offset wheels which increase the track of the car for greater stability. At high speeds, the APR Performance carbon-fiber GT wing supplies the downforce over the drive wheels for added traction.
The Reality
Expectations soared as the Hankook/Rockstar camp introduced its drivers and cars at the 2009 Formula D season opener in Long Beach. While back-to-back champion Tanner Foust was a proven commodity, there was a significant buzz as to whether this RWD-coversion, V8-powered Scion tC would stand a chance against the proven performers in Formula D. Pundits were quickly silenced when Foust and the tC captured third place in round one. Just three events later, the Scion tC earned its first event victory at the Las Vegas event (round 4). While Forsberg’s stellar performance this season will prevent a three-peat, Tanner and the Scion tC are likely to have a Top-5 finish this season and enough track time for a solid run at the champsionship in 2010.
