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The weak six-speed K series transmission was an issue with the car previously. The problem of nuking the stock transmission was solved with a call to Jeff “Kiwi” Owens at Special Projects Motor Sports who helped out with a Gear-X close ratio gear set and some meticulous rebuilding and reassembly of the transmission. The Gear-X gear set has much stronger gears and shafts that can take up to 600 hp. The gear set is a synchro gear set with helically cut gears so it can be used for street driven cars if needed.
The Gear-X gear set is a direct drop-in replacement for the stock gears and is a great heavy duty set up for high-powered K engined cars.
The limited slip differential that was in the transmission was completely worn out and it was replaced with an OS Giken one way differential. A one-way unit was chosen to reduce understeering on turn in.OS Giken did some custom set up tricks when taking the car's power level and type of tires into consideration.
When adding a stiffer cage the team was expecting the chassis tuning to be totally different. The amount of difference, however, was surprising.From Spoon Sports Japan, the car had very stiff springs and shocks with a low amount of damping. Although this seems counter-intuitive it worked surprisingly well with a very flexible chassis. With a stiff cage, the springs were now way too stiff and the shocks hopelessly under damped.
A call went out to KW Suspensions who built a set of custom 3-way Motorsports dampers for the car in record time.
The car uses front MacPherson struts and rear shock absorbers. The rear shocks are not coil overs and have the springs mounted inboard on the lower control arm independently of the dampers. This is a good method of mounting the springs as it isolates the dampers from spring kinking forces and can actually contribute to less tire shock due to the binding effect of the spring kinking force on the damper shaft.
The rear remote reservoirs are mounted inside the trunk area of the car and contain the high-speed and low-speed compression damping. adjusters. The rebound adjuster is on the top of the damper shaft.
With all of the adjusters close together and easily accessible, set up and tuning is much easier and quicker in the pits.
The front KW Motorsports struts use an inverted shaft for extra rigidity. To reduce stiction which is an issue with inverted shaft struts the KW strut tubes use linear ball bearing instead of bushings which ensure smooth friction free movement. The front strut remote reservoirs were mounted on the inner fender panels to ease access to the high and low-speed compression damping adjusters. The rebound damping adjustment is found on the end of the strut housing above the front axles.
Chris Marion from KW Suspension adjusts the compression damping on the Motorsports shocks.Since there was not enough time to test and set up the car, the Superlap Battle was treated as a test and many suspension changes were made during the event. Not ideal but the huge adjustment range of the KW dampers helped tremendously.
