The formula for making a luxury hybrid vehicle generally entails taking a model’s most powerful gas engine and adding even more power via an electric motor or two. Voila, there’s your brand’s flagship. Volvo knows what we’re talking about. So does Lincoln. You want the top-spec Porsche Panamera? That’ll be the 677-hp Turbo S E-Hybrid.
The Lexus LS takes a different approach. Instead of hybridizing the LS500’s standard 416-hp twin-turbo V-6, Lexus swapped in a 295-hp Atkinson-cycle 3.5-liter V-6. Even with the help of two motor-generators, the total system output is a pedestrian 354 horsepower. Which means that tacking an “h” to the badge of a LS500 results in a car that’s heavier, nearly a half-second slower to 60 mph, and $4560 more expensive than the conventional model. Last year, only 187 customers opted for the hybrid, proving that Lexus LS buyers are nothing if not rational actors.
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The 2019 Lexus LS500h Prompts Many Questions
From the Archive: Luxury Sedan Comparison Test
It would be one thing if the hybrid LS delivered Toyota Prius-like fuel efficiency, but even the Atkinson-cycle diet isn’t going to squeeze great fuel economy out of a two-and-a-half-ton sedan. In fact, the base rear-drive LS500 comes within 1 mpg of the all-wheel-drive LS500h’s 31-mpg EPA highway estimate. A similar 2019 LS500h with optional all-wheel drive that we previously tested averaged 19 mpg. During our 75-mph highway fuel-economy test we averaged 30 mpg, or 1 mpg shy of the EPA’s estimate. Sure, that’s better than the 17- and 26-mpg returns we saw from an all-wheel-drive LS500 F Sport, but that’s not the kind of difference that’ll change many minds.
It may be on-brand for Lexus to offer a hybrid version of its flagship sedan, but the LS500h’s driving experience doesn’t comport with the silken power delivery that’s defined the model ever since the first 1989 LS400. Toyota’s hybrid systems employ a continuously variable automatic transmission (CVT), but Lexus decided that a CVT isn’t refined enough for the latest LS. So, it bolted a four-speed transmission to the back of the CVT, then programmed the two gearboxes to work in concert to emulate a 10-speed automatic. Under full throttle, the complex multi-stage hybrid drivetrain does provide the impression of a conventional automatic, but under less frenetic driving conditions it gets wacky.
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For instance, heading downhill under braking—where you’d expect a hybrid to stay in EV mode and simply harvest energy—the V-6 sometimes burps to life, and the transmission gears down like a Freightliner cresting the Kancamagus Pass. The driver has no say in this matter, since mashing the EV-mode button often returns the message that EV mode is unavailable, for inscrutable computer reasons. With only 1.1 kWh of capacity from the lithium-ion battery, the LS500h’s EV mode might get you from the golf course’s front gate to the clubhouse, but only if you maintain a Club Car pace. On the plus side, the LS remains all-wheel drive even in EV mode.
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Just as a thought experiment, let’s imagine that we added the LS500h’s electric motors and their 59 net horsepower to the LS500’s standard twin-turbo V-6. Then you’d have a 475-hp hybrid that would likely return sub-five-second zero-to-60-mph times. Maybe it would get better fuel economy than the standard car. Maybe not. But anyone who really cares about that is buying a Tesla anyway.
But that car doesn’t exist. Which means that our ideal Lexus LS is also the simplest: rear-wheel drive, non-hybrid, steel springs instead of air springs—and a $76,475 base price instead of our all-wheel-drive LS500h’s near-$100K as-tested sticker. Rational actors, cast your votes.
Source: Reviews - aranddriver.com
