The IS250C represent Lexus’ second convertible and its first since the debut of the SC430 in 2001. Featuring a convenient single-switch operation, the new three-piece hard top provides open-air freedom with the top down without sacrificing the quiet and comfort of a coupe. Constructed primarily of lightweight aluminum, the hard top also provides surprising storage space but with low noise and increased security not typically found in soft-top convertibles. In addition, the top completely retracts with no elements remaining in view.
The four-link roof assembly, also made of aluminum for a lightweight design, provides smooth even movement. Engineered to operate in an easy, efficient manner, each component is motor driven with detection switches, allowing the control unit to know their exact position at all times. In addition to the two main roof panels being constructed of light-weight aluminum, the back window’s reinforced glass construction also lends itself to reduced weight. Weather-strip changes in areas around the doors and windows ensure tight seals.
A roof-speed brake-control system decreases the roof speed especially as it approaches the end of the closing operation in either direction, ensuring an elegant and quiet movement. On models equipped with available Intuitive Park Assist (IPA), sonar sensors in the rear bumper will stop the movement of the luggage door at the start of operation if it detects an obstacle will interfere. Also, a visual warning will appear on the instrument panel if a detected obstacle may soon interfere with top operation. When the IS convertible’s top is opened or closed, the power windows will automatically lower if in the closed position, and raise back up when the operating switch is held. Also, when the top is up, the door windows automatically lower 15 mm when the door opens, and then raise back into a fully closed position when the door closes. This ensures the doors’ clean open/close function while also maintaining a tight seal around the glass. The aluminum hard top features an automatic front lock assembly that provides the interior security not found in soft-top convertibles. When the top is stowed in the down position in the rear of the IS convertible, the lock assembly is engaged to kept the panel in a fixed, stable position.
Convertible Aerodynamics
The IS convertible has a best-in-class 0.29 drag coefficient (Cd). This is accomplished with the help of underbody covers below the engine (with aerodynamic steps), the full floor, and fuel-tank covers, as well as a rear-floor diffuser with vertical fin and airfoil. Other areas that contribute to the low Cd include the design shape of the outer mirrors, high-mount stop lamps, and the rear tailamps. Fender fairings before the front and rear tires reduce airflow into the wheel house, improving aero characteristics and reducing air turbulence.
The IS convertible models feature the same powertrain as the IS sedan. The IS 250C’s 2.5-liter V6 engine has a great combination of fuel efficiency and performance. The IS 250C’s V6 produces 204 horsepower at 6,400 RPM and 185 lb.-ft. of peak torque at 4,800 rpm. The engine utilizes aluminum cylinder blocks and heads, while employing dual Variable Valve Timing with intelligence (VVT-i), which controls timing on both the intake and exhaust camshafts. The IS 250 C comes with a paddle-shift, six-speed automatic transmission
