Liberating the Beast Within: Lexus Unleashes V8-Powered IS 430 ProjectDecember 29, 2003 — Los Angeles, CA –Lexus unveiled a one-off example of its IS 300 luxury sport sedan powered by a 4.3-liter V8 engine from a Lexus GS 430 in November 2003. Seeking to demonstrate the potential of the IS 300, Lexus commissioned Rod Millen Special Vehicles (RMSV) to build the car. The resulting “IS 430″ has since completed its development program with RSMV and is now road-ready.
“We wanted to explore the performance possibilities of the IS 300,” said Lexus Group Vice President and General Manager Denny Clements. “The marriage of our 4.3-liter V8 with the sporty IS 300 creates a classic muscle car.”
The potent V8 engine was paired with a Getrag 6-speed manual transmission and lightweight flywheel, which drive the rear wheels through a stronger limited slip differential and GS 430 driveline components.
Total Performance Approach
The concept direction from Lexus required that handling be matched to the high-powered V8 while maintaining reasonable ride comfort and noise levels. TEIN springs and 16-way electronically adjustable shock absorbers work with the original IS 300 front suspension in addition to selected GS 430 rear suspension components, which help ensure durability against the higher torque of the 4.3-liter V8. Large, sticky Michelin Sport Cup tires on 18-inch Speed Star SSR alloy wheels put the power to the ground.
A similar approach was taken with the cooling system and brakes. A GS 430 radiator was fitted to provide ample cooling for the high-output engine. Large Brembo brakes with vented, cross-drilled rotors and four-piston aluminum calipers are there to arrest the newfound acceleration and speed of the IS 430.
“The standard IS 300 is a robust and well balanced sport sedan, so we thought it would respond well to the additional power of the Lexus V8 engine,” said Rod Millen, president of RSMV. “With a package of complementary modifications, it has exceeded our expectations.”
Although not a simple conversion, the V8 and 6-speed fit well within the compact IS 300 body structure. Curb weight is slightly higher than the standard IS, some of which is due to larger/stronger components needed to deal with the increased performance and some from the new audio/video system.
“Fitting the 4.3-liter V8 and six-speed manual transmission to the IS 300 was fairly straightforward,” said Millen. “The larger challenge was to develop an electronic interface that would allow the V8 engine to work with the manual transmission and IS 300 body – something it was never designed to do.”
RMSV’s engineering team met the challenge with expertise developed through years of successful racing and building special vehicles for military and automotive clients. They focused on designing the electronics interface while simultaneously working through the mechanical conversion and enhancements. Numerous parts were specifically fabricated for the IS 430 including stainless steel exhaust headers and dual exhaust system, transmission adaptor, engine and transmission mounts, air intake system, wire harnesses and fluid connectors.
“Next Generation” Entertainment System
Pushing the IS 300 performance envelope was not limited to vehicle dynamics. Lexus also wanted to discover the potential of what might be termed a “next generation” in-vehicle entertainment system. Lexus naturally turned to its premium audio systems partner, Mark Levinson®, whose system engineers were eager to gain experience with their advanced system development work and receive feedback from users in the field.
The goals for the experimental system were the introduction of a discrete multi-channel 7.1 surround sound experience suitable for automotive use, complete system integration of audio and video, and advancement of sonic performance beyond previous OEM premium systems.
The result of their vision is a 20-speaker/24-channel, 720-watt* audio/video system using a proprietary DVD video player and removable 6.5-inch wide-screen video display. This prototype Mark Levinson® system is well suited to the expanded performance of the IS 430.
To complete the package, Chip Foose from Foose Design was employed to give the IS 430 a more aggressive yet functional appearance. Foose used subtle upgrades including a Rhys Millen Racing front lip spoiler and side skirts with a black over red exterior color scheme that emphasizes the wedge profile of the tightly drawn IS body. A mesh grille and gray headlamp treatment is used up front, and the taillights and rear badging are modified for a simpler look at the rear. The dual exhaust system’s twin tailpipes not only improve performance, but also help advertise the potent 4.3-liter V8 engine.
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Source: Lexus Press Release (lexus.com)