Four Door Flyer

So how would anyone attempt to prepare a four-door sedan for GT300 competition? By abandoning its original driveline and suspension configuration and starting from scratch. A TRD-designed cage reinforces the cabin of the IS350 race chassis and establishes a layout for component positioning. For optimal balance and weight distribution, the Toyota RV8J engine (sourced from Toyota’s formula Nippon racecar) takes its place midship where the back seats would ordinarily be located. A custom firewall now separates the driver from the engine. Although capable of over 500 horsepower, a pair of 25.3mm restrictors limits the 3.0-liter V8 mill per Super GT rules. A Pi Research engine management system controls fuel delivery and spark events, keeping all eight of the RV8J’s cylinders firing. A remote switch allows several engine tunes to be saved and selected to suit each driver’s particular style. Retuned for more midrange power, the resulting 300 horsepower keeps the IS350 within the GT300 class requirements.

Diffusers: Help or Hype?

Unlike some of the visual atrocities seen on streetcars, aerodynamic plays a real and important role in the world of racing. One component of aerodynamic tuning, the diffuser, improves the downforce on the chassis and reduces drag. Although not as noticeable as a lip spoiler or a wing, diffusers take the low-pressure, high-velocity air traveling under the car and facilitate a smooth transition as it expands back to ambient pressure.

Super Suspension

The GT300 class rules allow for significant suspension changes. To optimize weight distribution and reduced unsprung mass, the team opted for a cantilever- style suspension. This style of suspension, which is most common in open-wheel racecar designs, allows for large wheel/tire selection as well as easier adjustment and tuning of the suspension (ride height, spring rate, damper settings and motion ratio).

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Sophisticated Cockpit

The interior of this IS350 represents the state-of-the-art in racing hardware. The cabin features a plethora of strong but lightweight dry carbon-fiber panels and trim. The center console features a breaker panel instead of a bank of fuses. The breakers make re-reconnecting a circuit as simple as pressing a button. Next to the shifter, a pair of levers allow sway bar adjustments on the fly. Brake-bias adjustment is also within easy reach for fine- tuning of the braking system. Engine management, datalogging and communications equipment mount to the carbon-fiber interior, allowing easy access for tuning, maintenance and diagnosis. Catering to the individual driving styles of Orido and Kataoka, each driver can select their own customized engine tune by turning a knob on the dash.