The 3.5 RL has a stamped-sheet-steel unit-body structure that contributes greatly to an overall feeling of solidity and poise. Created with the same NASTRAN stress-analysis software used to design the space shuttle, this lightweight yet extremely rigid structure offers a high level of overall rigidity in both bending and torsion. The chassis is made even more rigid by a rear support gusset, a large bulkhead bracket and a rear crossbeam stabilizer.
The high rigidity of the 3.5 RL unit-body structure offers superb resistance to vibration while providing a firm platform on which to maximize the performance of the suspension system. Insulation has been added at critical points to reduce vibration and noise. Lightweight honeycomb panels in the floor provide additional structural stiffness and help absorb road noise. A high proportion of galvanized panels are used in the 3.5 RL structure and body panels for enhanced corrosion protection and overall longevity.
OVAL-SECTION FRONT TOWER BAR
Instead of a conventional tubular steel front brace between the firewall and the upper front-suspension locating points, the RL uses an oversized, oval-section tower bar brace, as well as a reinforced plate that ties the firewall to the front cowl section. This design increases rigidity as much as 12 times compared to a conventional round tube design, reducing cowl shake on rough roads and in spirited driving, while increasing steering precision.
FOAM-FILLED A-, B- AND C-PILLARS
For reduced cabin-noise transmission, the A, B- and C-pillars are filled with a special heat-expanding, rubberized foam material that expands to fill the hollow pillar during the baking cycles of the painting process.
HONEYCOMB FLOOR PANELS
Special lightweight honeycomb panels are used in the floor structure to increase rigidity and reduce noise and vibration. These panels are composed of a resin-impregnated fiber matrix bonded on top and on bottom to thin-gauge galvanized steel sheets.