Controlling Power Delivery and The Chassis

Converting power at the flywheel and putting it down to the pavement required a number of improvements as well. A J’s Racing-spec Exedy clutch transfers power to the factory transmission and propeller shaft. The propeller shaft turns a J’s Racing 4.7:1 final drive and J’s Racing 1.5-way limited-slip differential (LSD). Changing up the final drive to a 4.7:1 ratio takes advantage of the F22C engine’s power output and results in improved acceleration through additional torque multiplication. The 1.5-way LSD locks when acceler- ating, effectively dividing power evenly between the drive wheels. During decelration, the LSD unlocks to make turning easier. These characteristics are ideal for a circuit or street performance vehicle application.

Now that the power is being effectively harnessed, keeping the chassis planted to the pavement became the next area in need of attention. Generating good power means nothing if the chassis is out of control. The factory shocks and springs were replaced with a set of J’s Racing CRUX 2-way adjustable dampers and J’s Racing-spec Swift 16 kgf/mm springs. But improving the way a chassis handles entails more than just shocks and springs. When lowering the chassis, the roll center is moved, affecting wheel travel. Bump steer is another potential shortcoming that must be addressed. J’s Racing’s roll center adjusters, control arms, pillowball tie rods and L2 camber joints work together to correct the roll center of the chassis and eliminate the unnerving bump steer that results from changes in the suspension geometries.

Aero Tuning For Improved Handling

While the S2000 features terrific weight balance, power, suspension and handling, one shortcoming of the car is snap oversteer. This is a result of the relatively short wheel base of the chassis. At high speeds, a misjudged turn can have catastrophic results, usually spinning off of the track. To address this issue, J’s Racing designed its super-aggressive GT Wide-body kit for the S2000. This aero package features wider fenders at all four corners, allowing for more aggressively-offset 18-inch Volk Racing RE30 wheels wrapped with wide and sticky Bridgestone Potenza RE11 tires (255/35 up front, 265/35 in the rear). The kit also includes a front air dam and canards to maintain steady pressure over the front tires, while a J’s Racing 3D carbon-fiber GT wing and rear diffuser apply pressure over the rear wheels to balance the chassis and neutralize handling traits. In the end, the aerodynamics package evenly distributes downforce over all four tires, helping to neutralize the handling of the S2000.

Touge Showdown 300

Umemoto built the S2000 to serve not only as a test mule but as a functional demonstration vehicle. The car has made numerous appearances at car shows throughout Japan including the Tokyo Auto Salon. But this S2000 has also made appearances on video as well. Best Motoring DVD’s subsidiary Hot Version conducts an ongoing competition called Touge Showdown 300. The contenders compete on the touge with Japan’s celebrity pro drivers Keiichi Tsuchiya, Nobuteru Taniguchi and Max Orido as the test pilots. The J’s Racing has not only proved its prowess against S2000’s from Amuse and JUN, it’s also faced off against other platforms.