Tomei Powered/CUSCO/Voltex Subaru Impreza WRX STi: Technical Analysis Report

Being heavily involved in Super GT, Cusco took the initiative in engineering a chassis that is best suited for the conditions of the U.S. racetracks. Extensive data logged from the GT300 race car technology was adopted and applied to the unfamiliar U.S. time attack conditions. In essence, their creation is true to the saying "GT inspired." For each of their race chassis, Cusco's entire suspension and drivetrain components are calculated to extract the maximum performance from the tires. The current chassis and suspension setting for Team Tarzan's Impreza is accustomed exclusively for the Hankook Ventus Z214, which are highly sticky compounds to begin with. Cusco has spent an enormous amount of time developing a drivetrain system for their GT cars, which has substantially reduced friction characteristics. Of course, this technology has been applied to the time attack Impreza as well. Rubber engine and transmission mounts were replaced for completely solid units and to compensate for the added vibration, the entire frontend was stitch-welded and topped off with a Cusco power brace.

For the interior, rear crossbars were added to the rally bred, 22-point Safety 21 rollcage to comply with the strict NASA requirements. These 'cages are designed to handle up to two lateral g's while at the same time providing safety when the vehicle becomes upside down. The driver seat has also been offset slightly to the rear after considering weight distribution, combined with an extended steering wheel hub and organ pedals.

Engine performance and a stiff chassis are two essential aspects of a race car, however in the world where one-tenth of a lap time can make or break a record, aerodynamics must be taken into account. Voltex's genius aerodynamicist is also the president of the company, Akihiro Nakajima. He is responsible for creating some of the hottest-looking aero kits for Japanese vehicles today. These body kits are the most sought-after in the industry because every product is thoroughly tested for maximum functionality in a simulation wind tunnel.

The rear GT wing was set to provide a relatively mild level of downforce since this is the very first chassis Voltex tested. Voltex emphasized that it will be difficult to understand the reaction of the vehicle if a large amount of downforce is suddenly applied from the initial testing stage. Nonetheless, on an all-wheel-drive machine, the front tires absorb the majority of the stress, but it can be beneficial if rear downforce can be applied to alleviate some of this strain. The frontend, however, is a different story from the rear. A notable theory Voltex abides by is balancing the perfect ratio of incoming and outgoing air by the usage of specialized ducts, air directing sheet metal, and under diffusers. Unnecessary chassis lift may be experienced if improper calculations and misguided tuning is done. Since the front under diffuser produces massive downforce, it is securely fastened to the chassis to eliminate any movement. The aero kit seen on the Impreza can't be taken on and off easily, since it is a custom creation produced just for this project. Unfortunately for those Impreza enthusiasts, it is not available for sale nor are any production plans underway, but President Nakajima indicated that if there were enough demand, Voltex would fulfill the industry need.

Since each company involved with the build specializes in a single area of a vehicle, their combined efforts solved the funding obstacle of the project. It can be thought of as an all-star team where each member was assigned to an area of their expertise to make up the ultimate creation targeted toward one single objective. For Tarzan and the team, their goal to embark overseas to the U.S. time attack scene and shatter the existing record is drastically becoming a reality.