2018 Acura RLX Sport Hybrid Review

Pop quiz: What’s the most powerful Acura offered today?

If you said NSX, the Japanese luxury brand’s hybrid supercar, you’re spot on. But do you know which of its other five other models comes second in this under-hood arms race? That’s a tougher question to answer.

Not to leave you twisting in the wind, it’s actually the RLX Sport Hybrid, a partially electrified version of Acura’s somewhat forgotten large car. With a 377-horse stable, it’s also the company’s most powerful sedan ever, though the 196-pony chasm between it and the NSX is broad enough to make the Great Plains blush.

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Spacious yet unexpectedly economical, this four-door’s design has been spruced up for 2018 and its hybrid drivetrain further refined. Helping potential buyers, its trim structure has been greatly simplified as well, which should help demystify the shopping process. Properly sized and equipped, the company fancies it a foil to models like the Audi A6, Lexus GS, and BMW 5 Series, to name a handful of potential competitors.

Setting the 2018 Acura RLX apart from today’s model is a freshened exterior. The biggest change is undoubtedly the first thing you’ll notice about this sedan. Up front, it’s now graced with the brand’s signature Diamond Pentagon Grille, which helps it visually fit in with the rest of Acura’s modern lineup, though it’s not necessarily an improvement over the outgoing “beak” front end that so many pundits griped about.

Aside from the obvious – that grille is impossible to ignore, ditto for the imposing Acura emblem, which has got to stand at least eight inches tall – its front fenders, hood, headlights, wheels, sills and much of the rear end has been redesigned, giving the car an appropriately cohesive look. Seven exterior colors are offered, six of which are new to the RLX. This palette also features four different interior hues including a chocolatey Espresso option.

The car’s two-screen infotainment/climate-control system certainly provides some benefits, but many of the graphics look like they were designed to run on Windows 3.1. The user interface is likewise confusing, while the discrete digital clock seems like a stowaway from the 1980s.

One other minor complaint is that the car features “woodgrain” finishes throughout, industry-speak for phony plastic trim. While not overly offensive, real timber accents certainly would have been appreciated.

Upping the ante, Sport Hybrid versions of the RLX get all-wheel drive provided by an advanced three-motor powertrain that shares components with the NSX. Instead of running a separate driveshaft and differential to the rear axle, a twin-motor assembly spins the back tires and even provides torque vectoring, which allows the vehicle’s rear end to rotate while cornering.

Hybrid models also feature a 3.5-liter V6 as well as a quick-shifting seven-speed dual-clutch automatic transmission. Serving as an electron reservoir is a small 1.1-kWh lithium-ion battery pack, which is nestled in the trunk where it doesn’t eat up too much space, allowing the car to swallow up to 12 cubic feet of junk (340 liters), a minor loss compared to the P-AWS model’s boot, which is rated at 14.9 cubes (422 L).

Add it all up and the Sport Hybrid delivers 377 horsepower and 341 pound-feet of torque, a healthy upgrade over the P-AWS car. It’s also unexpectedly efficient, returning 28 miles per gallon city and 29 highway. Combined, this large sedan should average 28 mpg, five more than the gasoline-only RLX.

In addition to the hybrid system, Variable Cylinder Management helps deliver those impressive efficiency scores. Half the engine’s pots can be deactivated under light loads, further reducing fuel burn, but the car will not run on battery power alone. One point worth mentioning is that Acura’s 3.5-liter V6 still uses a timing belt (instead of a chain like many other manufacturers) to drive the camshafts, which can be costly to replace, though to be fair, that’s only every 100,000 miles.

True to form, the RLX’s gasoline engine is silken and responsive, revving with verve while emitting a pleasant intake rumble. It also seamlessly shuts down when the car is stopped or coasting, starting up imperceptibly and in the blink of an eye when power is required again.

While not bone-crushingly quick, this large sedan is nonetheless plenty fleet, even while climbing hilly terrain. In the age of forced induction, it’s also nice to feel a naturally aspirated engine, especially one that pulls as smoothly and linearly as this Acura’s.

Despite being equipped with a dual-clutch transmission, shift quality is not a problem. These fuel-saving gearboxes often have refinement issues, but never during testing did the Sport Hybrid’s judder or jerk. Shifts up or down were consistently quick and seamless.

Aggressively dip into the throttle while cornering and this partially electrified RLX’s rear end will step out, though this dance move is neither aggressive nor sudden, rather gradual and controlled. It provides just enough tail-happiness to put a smile on your face, not smudges in your under-breeches.

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If there’s a dynamic disappointment, it’s Sport Hybrid’s steering. Weighting is on the heavy side and it’s certainly heftier than what’s provided by an Audi A6’s tiller, a competitive model the company had on hand for back-to-back tests, but the car never seems to settle into its lane. The RLX likes to wander, seeming to require careful attention, even when lane-keep assist is enabled.

Still, the drive is nicer overall than what’s provided by its German rival, which felt slower in a straight line and less communicative through corners, plus its front seats were much less comfortable. But in Audi’s defense, the A6 is quite old at this point and scheduled to be replaced soon.

The Sport Hybrid’s quality is pretty middle of the road – firm but allowing for large body movements over certain sections of undulating pavement. On well-kept surfaces, there’s nothing to crow about here, but residents in areas of the world where the roads are in more severe condition might find the RLX a bit stiff. Unlike many rival sedans, adaptive dampers are not offered.

Like other Honda products, the RLX comes with a bevy of standard driver assistance features. The company’s AcuraWatch suite includes technologies like adaptive cruise control, forward collision warning, and lane-keeping assist. But one of the most helpful is Traffic Jam Assist.

As its name implies, this feature takes some of the stress out of driving in slow-moving congestion by centering the car in its lane and maintaining a safe distance between the vehicle ahead. Tested on one of Los Angeles’ clogged thoroughfares during rush hour, it worked impressively well, steering the vehicle largely on its own while eliminating the need to operate the pedals.