Lexus IS250C

I came across this baby just the other day. It was at night, parked with all those lights on. I couldn’t help but notice it. You can’t honestly tell me that it’s inconspicuous. And then I came across another one, a red one during broad daylight and I thought to myself, I have got to let you guys know a little bit more about it.

Making its world debut at the 2008 Paris Motor Show and on sale throughout Europe in the summer of 2009, the new IS 250C combines the award winning design of the IS sports sedan range with outstanding open-top engineering ingenuity.

Reflecting Lexus’ legendary quality and attention to detail in every aspect of its construction, the new IS 250C convertible has been designed to exceed customer ownership expectations in every respect. Representing a unique fusion of top-down driving pleasure and uncompromised dynamic performance, its lightweight folding aluminium roof structure boasts the world’s fastest three-part roof opening time of just 20 seconds.

Sharing the IS 250’s 153kW, 2.5-litre ultra-smooth V6 powerplant and 6-speed automatic transmission, the new Lexus convertible has been styled to offer minimal wind turbulence when driving with the hard top stowed. Extensive revisions to body structure and suspension equip the IS 250C with the torsional stiffness necessary to promote ride comfort appropriate to the brand and, in coupe guise, the reduced noise, vibration and harshness (NVH) characteristics on a par with those of the IS sedan.

Thanks to the remarkably compact packaging of its three-part folding roof mechanism, the IS 250C offers a large boot space, generous rear seat access and spacious rear passenger accommodation.

Exterior design
Building on the elegant proportions, sweeping sculptural lines and powerful contrasts in convex and concave surfacing that identify the Lexus IS sedan range, the new IS 250C’s design combines the muscular appeal of a dynamic, sporting coupe with the open-topped elegance of a stylish, comfortable and superbly refined convertible.

Offering a unique style that differentiates the IS 250C from conventional convertibles, only the IS 250C’s bonnet, headlamps, door handles and mirrors are common to the IS sedan. All other body panels have been redesigned to harmonise perfectly with the integration of the new convertible’s three-part, aluminium folding roof.

A new fog lamp design is integrated within the deep front air dam. In profile, the coupe/convertible’s powerful, sporting stance is characterised by elegant, muscular coachwork below a pronounced, rising beltline that kicks up towards the rear. The steeply raked windscreen flows seamlessly into the smooth, clean, aerodynamic arc of a roofline which penetrates the boot surface via a crisp, elegant C pillar design incorporated within the folding roof structure. In coupe guise, the cabin tapers elegantly to the rear, allowing for a fluid roofline transition from C-pillar to luggage compartment. To the rear, the IS 250C features new combination tail lamp clustres with instantly recognisable, linear LED illumination, and a high-mounted LED stop light integrated within a sleek spoiler on the upper boot lip.

With the hard top stowed, the IS 250C presents a seamless, elegant profile punctuated only by the integral roll-over hoops behind the rear seat headrests, reinforcing the full-length sweep of the rising beltline and the convertible’s broad, purposeful rear stance. No residual roof mechanism elements remain in view or project above the vehicle’s tapered waistline; the whole being entirely concealed beneath the broad, sweeping boot surface and adjacent, flush-fitting parcel shelf.

Constructed entirely in lightweight aluminium, the new IS 250C’s folding roof structure offers an unparalleled level of smooth, seamless and silent operation. Activated via a dashboard-mounted button, the ultra-quiet operating mechanism features a unique “roof brake” mechanism that slows the closing of the hard top as it approaches the windscreen head. This ensures that, unlike many mechanisms in which the weight of the roof structure causes an increase in operating speed just before the point of closure, the IS 250C’s hard top descends smoothly into place.

Interior design and comfort
The IS 250C shares the sedan’s high levels of interior luxury and practical innovation, with several bespoke technical revisions designed to ensure the effective operation of the vehicle’s on-board comfort and entertainment systems when in convertible configuration. On board, the instrument panel and surrounding components, as well as the steering wheel, are shared with the IS sedan range, but the driver’s instrument binnacle has been extensively revised to increase open-topped motoring visibility.

The climate control system has been specially configured for top-down motoring with the addition of a speed sensitive control which automatically increases air flow in roof-open mode, and further increases airflow according to vehicle speed.

The 12 speaker, Mark Levinson® Premium Surround Sound system features equaliser tuning to provide consistent audio quality whether the hard top is up or down, automatically adapting to the natural loss of bass when the roof is stowed.

Set 30mm further inboard than those of the IS sedan to optimise headroom and divided by a centre console with built-in cup holders, the two, full-sized rear seats benefit from a revised, more slender front seat profile to offer ample legroom.

Improved by a wide-aperture door 300mm longer than that of the IS sedan, rear seat access has been simplified through a one-touch walk-in button offering high-speed, automatic front seat fold-and-slide activation for the ultimate in rear passenger convenience.

The IS 250C’s rear overhang has been increased by 50mm over the sedan, which combines with the exceptionally compact packaging of the folding roof to generate a significant increase in luggage space. The new Lexus can accommodate a 9” golf bag with the hard top stowed and the luggage cover in place.

Aerodynamics and Wind Stream Management
Benefiting from a steeply raked windscreen, ultra-smooth cabin profile, aerodynamically efficient, “duck-tail” rear styling featuring “airkick” effect, rear tail lamp clustres, and a comprehensive array of aerodynamic under-body covers, the IS 250C has been designed to combine the lowest possible drag coefficient with minimal wind turbulence affecting the open cabin. Hard top in place, the IS 250C’s drag coefficient of just 0.29 compares extremely favourably with the sedan’s exceptional 0.27Cd rating.

Lexus design engineers have focused particular attention on reducing wind turbulence and generating the most comfortable airflow characteristics for occupants with the hard top lowered. The angle of the front windscreen allied to the windscreen head design are major contributors to the achievement.

Ride comfort
The new IS 250C employs the proven double wishbone front and multi-link rear suspension format of the IS sedan range to offer a sporting, agile driving experience. Significant chassis revisions have been incorporated to promote the greater ride comfort appropriate to a convertible, and ensure a consistent dynamic performance in both coupe and convertible guise.

In conjunction with extensive temperature, vibration and shaking tests, all bodyshell and chassis revisions have also been implemented with the express aim of ensuring that, in coupe configuration, the IS 250C demonstrates almost identical Noise, Vibration and Harshness characteristics to those of the IS sedan. The use of acoustic windscreen glass allied to painstakingly optimised roof, door and window panel seals awards the IS 250C class-leading low wind noise levels.

Safety
The IS 250C has been designed to achieve a 5-star frontal impact rating in Euro NCAP crash testing, offering world-class safety in either coupe or convertible configuration. Numerous body structure changes have been incorporated in the IS 250C to enhance collision strength, roll-over protection and torsional rigidity, minimising scuttle shake and optimising chassis controllability.

In keeping with the IS sedan range, the new Lexus convertible benefits from the highest content of sophisticated active and passive safety technology in the segment, including Lexus’ Vehicle Dynamics Integrated Management (VDIM) incorporating open body-specific Vehicle Stability Control (VSC) tuning for shorter stopping distances on split-friction road surfaces, a revised Pre-Crash Safety (PCS) system which supports the pre-crash seatbelt and pre-crash brake assist functions with pre-crash brake technology, and the Safety Restrain System (SRS) twin-chamber passenger airbag.

Further improving the new Lexus safety credentials in open-topped mode, the IS 250C is equipped with a new design of enlarged side airbags which provides head protection in the event of side impact. The convertible bodyshell has also been equipped with additional, energy absorbing side impact pads for both front and rear seat occupants.

Source: Lexus