Absolute rigidity is necessary for consistency and predictability in a racecar. The front of the cage is anchored to the firewall because it can't extend forward of that point, so the team used the same bolt-on braces for the front shock towers available from Toyota Racing Development (TRD).
The seat resides slightly rearward and inboard of the stock position, but is mounted very low in the car for a lower center of gravity. As a result, the view over the hood is somewhat limited.
Reservoirs for all four ProTrac adjustable shocks are mounted in the area where the back seat would be in a stock IS 300. This is the usual spot for the rear shock reservoirs, but the fronts usually live under the hood. Putting the reservoirs in the same place yields multiple benefits. The back seat is far cooler than under the hood, so the shocks are less prone to fade.
Putting all four reservoirs in close proximity means the mechanics can quickly make adjustments to compression and rebound settings for all four shocks at the same time. Finally, having access through the back doors means the crew can work on the settings while standing beside the car.
In the event the car pitted behind the IS 300 overshoots its pits during a stop, it'd hit the car and push it into crew members standing in front of it. Standing beside the car, injuries are likely to be minor in the event of a pit lane collision.
Counter-intuitively, the racecar's 3.0-liter engine is stripped of the street car's VVTi variable valve timing equipment. VVTi is useful for good low-end power and meeting strict emissions requirements. It's not necessary for the high-rpm demands of racing and adds weight to the top of the engine, which is bad for the car's center of gravity. The team runs OEM cams from an early Supra.
Fitting the six-speed Supra gearbox discombobulated the ECU, which only works with the factory slushbox. To remedy this, Team Lexus installed an aftermarket computer to run the engine, sacrificing the stock ABS circuitry. In the absence of ABS, a proportioning valve balances the brakes, front to rear.
The powerful front brake rotors and calipers are out of the Lexus parts bin and are equipped with TRD pads manufactured by Performance Friction Corp. At the rear, the IS 300 relies on its stock brake set-up, also outfitted with the TRD/PFC pads.
The six-speed transmission was approved for Grand Am racing, even though the U.S.-spec IS 300 is fitted with a five-speed. When it was submitted for approval in 2000, Lexus hadn't decided whether the United States would get the Japanese five-speed or the European six.
Behind the Wheel
During our drive of the car around the twisting infield road course of Pikes Peak International Raceway, we were asked to shift at 6000 rpm, just shy of the engine's true 6500 rpm redline. That was fine with us. Without our usual test equipment on hand, lap time wasn't a priority. We just wanted to get a feel for the thing.
Untouched internally, the inline six-cylinder engine pulls strongly, but lacks low-end punch. The TRD low-restriction intake and exhaust boost the engine's output at higher revs, which is where the engine spends most of its time.
Insulation wrapped around the exhaust ushers heat out of the engine bay and wrapping on the intake pipe keeps under-hood heat from reaching the intake charge. The growl through the system, however, is satisfying but too loud for street use. Aside from the exhaust, a dedicated tuner can duplicate most other modifications.