SAN FRANCISCO – Acura receives plenty of criticism for being a premium brand without a production V-8 engine.

But finally the marque has an offering for its detractors in the form of the new 3-motor RLX Sport Hybrid, on sale spring 2014 in the U.S.

The sedan, based on the new-for-’13 RLX, brings not a V-8 but rather V-8-like power to the brand.

The RLX hybrid’s 377 hp and 377 lb.-ft. (511 Nm) of torque bests other V-6 hybrids’ output, such as Lexus’ 338-hp GS 450h and Infiniti’s 360-hp M Hybrid, and gives the car a sporty personality the standard RLX lacks.

Buyers should not be scared by the word “hybrid.” WardsAuto’s test of the model here in early December proved it is the least-hybrid hybrid we have ever driven.

There’s no noticeable shock from the engine restarting out of stop/start mode, no grabby brake feel and scant electric-motor whine, except at very slow creeping speeds.

The RLX Sport Hybrid has the RLX’s 310-hp 3.5L direct-injected V-6 and, as with most hybrids, an electric motor up front. The 35-kW (47-hp) unit, integrated into the 7-speed dual-clutch transmission, also acts as a generator and makes 109 lb.-ft. (148 Nm) of torque from 500-2,000 rpm.

What is groundbreaking are the car’s twin rear motors, each generating 27 kW (35 hp) at 4,000 rpm and 54 lb.-ft. (73 Nm) of instantaneous torque.

The rear motors, laid out left-right between the wheels, take the place of the rear differential for Acura’s Super-Handling All-Wheel-Drive system and drive the car at launch and during low-speed cruising, as well as provide regenerative braking during deceleration. It’s a similar idea to Bosch’s motor-driven rear axle seen in the Peugeot 3008 diesel hybrid in Europe.

The rear motors can send positive torque to the outer rear wheel and negative torque to the inner rear wheel during cornering, with more torque transmitted as needed in tight maneuvers.

All the power pathways are illustrated in a nifty torque-vectoring display available on an Acura-first head-up system or the center stack’s top screen.

In back-to-back tests against the GS 450h and an Audi A6 3.0T, the RLX hybrid is the most stable cornering above 50 mph (80 km/h) and the electric AWD quells, although not necessarily eliminates, the understeer prevalent in the front-wheel-drive non-hybrid RLX. The A6 has the worst handling of the bunch in our tests, rocking and rolling through the switchbacks like Santa’s overstuffed sleigh.

RLX Sport Hybrid Chief Engineer Hitoshi Aoki says the car can travel on electric power alone (all three motors feeding the car’s 1.3-kWh lithium-ion battery pack) up to 50 mph for 2 miles (3 km), presuming a fully-charged battery.

We confirm this, but one must keep close watch on the torque-vectoring display to notice time spent in EV mode. Transitions between engine and battery power are imperceptible, and the car lacks a typical “EV” indicator light on the gauge cluster.

Most drive time here is spent in Normal mode (there’s no Econ mode, as Aoki says Normal is fuel-efficient enough). But in the afternoon, we switch to Sport mode and the car comes alive.

Tip-in is much more eager and acceleration faster, though fuel economy suffers.

A low-speed leg, along the Pacific Coast Highway to the nearby coastal town of Marshall nets a 32-mpg (7.4-L/100 km) average, besting the RLX hybrid’s 30-mpg (7.8 L/100 km) EPA-estimated combined rating. The Sport-mode route returns 25.5 mpg (9.2 L/100 km). That’s not great, but it’s still better than the EPA-estimated averages seen in non-hybrid V-6 sedans, including the gasoline-engine-only RLX’s 24 mpg (9.8 L/100 km).

Another bit of standout technology on the RLX Hybrid is the car’s 7-speed transmission.

Honda’s first DCT sets the standard for the gearbox. If it wasn’t for tachometer needle movement you’d never know shifts were occurring.

The RLX Hybrid’s interior is a mixed bag.

The space is roomy and comfortable. Front seats are nicely contoured, not wide and flat as those in the A6 and GS 450h. Rear legroom is ample, even in the middle seating position, although outboard headroom is tight.

The sedan has Acura-typical great fit-and-finish and some nice attention to detail, including sharp metal-look speaker grates on doors.

But it falls short of other V-6 hybrid competitors and some V-8 models due to cheaper materials.

Grab bars are hard plastic, not wrapped with leather or a similar soft material; wood trim is fake, not the real deal, and door padding is on the thin side.

But perhaps the biggest flaw of the RLX Hybrid is it shares a center-stack layout with Honda, the overwrought dual-screen system.

The latter dinged the Accord in this year’s Consumer Reports annual reliability survey and for good reason: You’re never quite sure which information you should be seeing on which screen, or how the info on the screens is getting there.

And the menu structure is needlessly complex. It should not take two screen touches to turn off the air conditioning.

For Acura to be considered a true luxury brand it needs to craft a unique, simplified center stack, and not employ one from its lower-priced sister brand.

The flaws are glaring, especially with Acura hinting it will price the RLX Hybrid at $60,000-$65,000.

The 48-year-old male, married, healthcare/financial services/real-estate professional target-buyer has a lot of choices at that price point, including BMW’s AWD, high-mileage 535d sedan and Mercedes’ E550 4Matic, as well as the less expensive Mercedes E250 diesel and E400 hybrid models.

The RLX Sport Hybrid technology is worth $60,000-$65,000, but the Acura badge can’t command the same premium as BMW or Mercedes. We’ve seen the brand unsuccessfully try to compete dollar-for-dollar with the Germans before, most recently with the slow-selling ILX compact sedan.

If Acura can get the RLX hybrid’s price down a bit, improve the interior and market it well, it has a shot at getting the credit it deserves for this technological marvel.

cschweinsberg@wardsauto.com

'14 Acura RLX Sport Hybrid
Vehicle type 5-passenger, AWD compact car
Engine 3.5L direct-injected V-6, all-aluminum head/block
Power (SAE net) 310 hp @ 6,500 rpm (Total system: 377 hp)
Torque 273 lb.-ft. (205 Nm) @ 4,700 rpm (Total system: 377 lb.-ft. [511 Nm])
Bore x stroke (mm) 89.0 X 93.0
Compression ratio 11.5:1
Transmission 7-speed dual clutch
Wheelbase 112.2 ins. (2,850 mm)
Overall length 196.1 ins. (4,982 mm)
Overall width 74.4 ins. (1,890 mm)
Overall height 57.7 ins. (1,466 mm)
Curb weight 4,312 lbs. (1,956 kg) with Technology package (4,354 lbs. [1,975 kg] with Advance package)
Price TBD
Fuel economy 28/32 mpg city/hwy est. (8.4-7.4 L/100 km)
Competition Infiniti M Hybrid, Lexus GS 450h, Audi A6 3.0T, Mercedes-Benz E550, BMW 535
Pros Cons
Good fuel economy for 377-hp car Pricier than some comps
Roomy, comfortable interior Honda look-alike center stack
Unique 3-motor design Lots of tech-y choices in segment