Toyota rethinks the flagship

  • 22-Oct-2017 07:48 EDT
2018 LS500 FSport Oct17 sessions.jpg

2018 Lexus LS500 F Sport in profile shows new GA-L platform stance on 123-in wheebase. Overall length is 206.1-in. (Ron Sessions)

Toyota has engineered a complete road-to-roof redo of its flagship Lexus LS sedan, dropping the V8 engine in favor of a twin-turbo V6, adding Aisin's new 10-speed planetary automatic and retaining a hybrid-electric powertrain option, among many changes. The 2018 model marks the fifth generation of the car that rocked the luxury-sedan establishment almost 30 years ago. While the LS has represented less than 2% of the brand’s U.S. sales in recent years, its significance to Toyota exceeds its sheer numbers.

Chief Engineer Toshio Asahi and his team began work on the new LS500 and hybrid LS500h in late 2011. One key goal was to attract a younger buyer with what Asahi calls “Brave Design,” picking up the Lexus family ‘spindle’ grille theme and developing a longer, more muscular exterior form. Lowering the hood by 1.2 in (30.5 mm),the decklid by 1.6 in (40.6 mm) and dropping the roof 0.6 in (15 mm) versus the 2017 LS help the new version look more ground-hugging as well.

The 2018 LS500 shares Toyota’s new GA-L global luxury platform with the LC coupe. There’s just one wheelbase (123.0-in/3124mm) offered and the car’s 206.1-in (5232-mm) overall length exceeds that of last year’s long-wheelbase LS460L by an inch (25.4 mm). Among competitors, the new LS is sized between the slightly more abbreviated Cadillac CT6 and fractionally longer Mercedes-Benz S-Class. The LS’s front wheels are pushed forward for the desired longer dash-to-front-axle aesthetic and the rears moved back for a gain of 2.2 in (56 mm) more rear seat legroom.

New HMI, lower H-point

Sumptuous interiors have been a pillar of the Lexus luxury reputation and the new LS offers a lot to catch the eye. But there’s also plenty of technology. A standard 8-in driver information display and a 12.3-in-wide (312-mm) infotainment monitor are arrayed across the center of the dash, with a 24-in-wide head-up display optional. Images shown in the HUD include vehicle speed, gear selected, road signs, safety system notifications for such things as front cross traffic warnings and pedestrian alerts as well as navigation information about upcoming turns.

Between driver and shifter is the new remote touch interface. It now works less like a computer mouse and more like a smartphone with swipe and pinch control. Standard Lexus Enform Wi-Fi ushers in-car internet connectivity to up to five devices courtesy of Verizon 4G LTE service and an optional 23-speaker Mark Levinson surround-sound system brings 16 channels and 2400 watts of auditory immersion.

But the most striking aspect of the new LS is its craftsmanship and attention to detail or Takumi, something Asahi-san feels is central to Lexus “moving from a luxury car brand to a luxury lifestyle brand.” Interior occupants are cocooned with soft-touch surfaces and generously padded contact points. The sides of the console and armchair-caliber door armrests are backlit with small LEDs and appear to be free standing from the doors. Available interior upgrades in the Executive Package include door trim with handmade origami-like cloth pleats, and interior trim-panel pieces fashioned from hand-cut flame- or herringbone-pattern wood. Intricate laser-cut and polished Kiriko glass is also available.

Nestle into one of the highly supportive and all-day comfortable multi-adjustable front buckets and you may notice that a lower H-point than in the previous model. The seats impart a lower center-of-gravity feel that’s central to the new LS’s sportier feel. A new access mode (available with the optional air suspension) raises the car 30mm (1.2 in) for ingress and 10mm (.39 in) for egress—part of the Omotenashi tradition of Japanese hospitality, Lexus says.

Vehicle dynamics and the LS

According to Asahi, Lexus studies discovered a change in the priorities of LS buyers. Previous owners were focused on status whereas new customers were seeking something more experiential. In short, make the LS more of a driver’s car, beginning with a stiffer body structure. Engineers greatly increased use of high-strength steel in combination with aluminum fenders and door, hood and decklid outer panels, and cast-aluminum strut towers. There’s also extensive application of structural adhesives—something Toyota was late to adopt—laser screw welding for increased panel joint rigidity. The new car is about 500 lb/227 kg heavier than the 4651-lb/2110-kg model it replaces.

Steering accuracy is improved courtesy of double ball-jointed upper and lower control arms in the front suspension. Toe-control links in the rear add lateral stiffness for greater linearity in response to steering input, Asahi noted. Standard on the new LS is an adaptive variable suspension (multilink front, 5-link rear with optional air springs) featuring active damping. The system’s linear-solenoid actuators have 650 different settings to respond to inputs from G-force, yaw-rate and vehicle-speed sensors. As a result, body control proved exemplary over swells, sharp dips and bumpy sections of road during Automotive Engineering’s test drive.

And despite exclusive use of run-flat tires on 19- or 20-in alloy wheels, impact harshness over rough stretches of pavement meets expectations of this segment. All but one wheel design has a hollow-chamber rim section to absorb road noise.

Also new for 2018 is an F Sport package which adds larger front and rear brake rotors, more powerful calipers (6 pistons front, four rear) plus optional summer tires. The active rear steering, an LS feature since 2012, provides greater high-speed stability and improved low- and mid-speed steering response, engineers said.

Powertrain and hybrid

The 2018 model is the first Lexus LS without a V8 under the hood. In its place is Toyota’s all-new long-stroke (100mm) V35A-FTS twin-turbocharged 3.5-L DOHC V6 that shares nothing with the 3.5-L V6 Lexus used for years in other models. Along with the pair of turbos integrated into the exhaust manifolds there is much new technology here: electronic wastegates, dual VVTi intelligent variable valve timing, Denso 4ST direct fuel injection combined with port injection, and high-flow laser-clad intake valve seats first detailed by Toyota in a 1992 SAE Technical paper (http://papers.sae.org/920571/).

The 416 hp (310 kW) of the new V6—rated on 95 RON premium unleaded fuel—tops that of last year’s 4.6-L V8 by 30 hp (22 kW), and there’s an extra 75 lb·ft (102 N·m) available from 1600 to 4800 rpm. On rear-drive versions, 0-to-60 mph acceleration improves to a claimed 4.6 s, about 1.5 s quicker than the 2017 car. Turbo lag is practically nil and midrange part-throttle tip-in delivers satisfying thrust that minimizes downshifting. A high-flow exhaust adds some voice. Active noise control working through the car’s audio speakers takes care of unwanted low-frequency booming when cruising along at low rpm.

Augmenting the V6 is a new wide-ratio version of Aisin's AWR10L65 10-speed 'Direct Shift' planetary automatic shared with the LC500 coupe. It’s fitted with a lower first gear for quicker acceleration and taller top gears for relaxed cruising and improved highway fuel economy. Standard steering-wheel paddle shifters enable manual shift control, but except for aggressive back-road blasts or steep mountain downgrades the 10-speed automatic’s programming predicts what gear is needed for a given situation so well that the driver can concentrate on steering, accelerating and braking.

Available all-wheel drive makes the LS usable year-round in cold climates. Its Torsen limited-slip differential can send as much as 48% of drive torque to the front wheels. On dry roads, it can send up to 69% of torque to the rear wheels. Lexus expects as much as 35% of LS sales will be AWD models.

Being a Toyota product, of course there’s a hybrid version. The LS500h offers a combined output of 354 hp (264 kW) produced by the 3.5-L Atkinson cycle V6 (8GR-FXS) and two electric motors. The system is now a multi-stage design with powerflow working through a CVT and 4-speed planetary gearset. The result is a more natural step-shift feel and no real “rubber band” sensation during brisk acceleration. And because the 2018 LS500h uses a more compact lithium-ion battery, it offers considerably more trunk space than last year’s LS600h with NiMH battery.

A plug-in hybrid is not available yet; Toyota feels the U.S. charging infrastructure remains insufficient. Rear-drive models get a 25 mpg city/33 mpg highway EPA label with a 600-mile (966 km) range; AWD hybrids drop 2-3 mpg from that.

The new LS goes on sale in February 2018. Base price in the U.S. had not been announced as this article went to press, due to exchange-rate variables. But Lexus expects to bring the Tahara-built flagship in at around $75,000 USD. Fully optioned examples are anticipated to top $100,000.

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