Acura RLX

	Acura RLX / Legend
	Debut: 2013 Maker: Honda Predecessor: Legend Mk4 / Acura RL (2005)

Published on 29 Jun 2013

Some background information first. Introduced in 1985, Honda Legend was the first Japanese luxury car to find sales success in the United States, where it was initially branded as Acura Legend and later on Acura RL. However, its hey days faded out since the mid-1990s when German premium brands and Lexus switched on afterburners. Without a luxury car synergy, Honda could not afford to develop a dedicated luxury car platform for the car, therefore the Legend/RL remained front-wheel-drive and V6-powered throughout the years and gave people the impression of a "Big Accord". In the last generation, Honda tried to change that impression by introducing a torque-vectoring 4-wheel-drive system called SH-AWD, which did improved its handling considerably, but the rest of the car remained relatively cheap and failed to lure buyers from the luxury camp. For this generation, it has an uphill battle to fight. Not only its rivals are getting stronger but the call for reducing fuel consumption also puts pressure on the cost side. Can it change its falling fate?

Frankly, I don't think so. The new car, although renamed to RLX, is built largely on the same formula as its predecessors. Honda has no ambition to lift the Acura brand to the same status as Lexus, which would be probably too costly and risky in the eyes of its senior executives. Therefore the car remains to be a front-wheel-drive, V6-powered machine derived from the architecture of Accord and TL. There will be a version offering a high-tech electric rear axle called Sport Hybrid SH-AWD, but even the marketing guys admit the majority of buyers (over 90 percent) will choose the entry-level model without this feature. As a result, the RLX will be difficult to compete with top tier rivals like BMW 5-Series, Mercedes E-class, Audi A6 (most sold with Quattro), Jaguar XF and Lexus GS. On the other hand, it is too expensive to play in the Division 2, which consists of Chrysler 300, Hyundai Azera, Kia K7/Cadenza, Lexus ES and Hyundai Genesis. Its prospect is really worrying.

Worse still, it also lacks a head-turning design to attract new buyers. Apart from the jewel-effect full-LED headlamps, its exterior design is ordinary to the extent of sleepy. It could easily get lost in a car park. The interior, too, lacks character as well as the sense of luxury you may find on some rivals.

Well, at least it offers more space than the outgoing car. Measuring 5 meters long, 1.9 meters wide and running a 2850 mm wheelbase, it is larger in all dimensions. This reflects in the cabin, too. The rear legroom is now class-leading, something also helped by its FF layout. It also gives the most front and rear shoulder room. There are now not one but two LCD screens. The upper one is used for navigation and the lower one is for radio and climate controls, though it takes some getting used to. The interior is comfortable and well equipped, but the same could be said to most of its rivals.

At 1.8 tons, the RLX is about 50 kg lighter than the old RL, although the latter did sport 4WD as standard. Meanwhile, torsional rigidity is increased by 46 percent. This is achieved by using more high-strength steel (55 percent of the chassis by weight) and a lot of aluminum, such as the bonnet, boot lid, front fenders, door skins and even structural parts like front subframe and bumper beams. That said, it is still heavier than its German rivals by a few dozens to 100 kilograms.

Compared with its rivals' forced induction six-cylinders, Honda's naturally aspirated 3.5-liter i-VTEC V6 is more about linearity than flexibility. Now equipped with direct injection and VCM variable cylinder management, which shuts down one bank of cylinders under light load to save fuel, it should be frugal enough, but the old-fashioned two-stage VTEC and the lack of light pressure turbo explains why its peak torque is only 272 lbft, and it is delivered at a rather high 4500 rpm. For comparison, BMW 535i provides 295 lbft from merely 1200 rpm. Its maximum horsepower of 310 is competitive, but on the road it doesn't feel as potent, blame to the relatively peaky delivery and the extra burden it has to propel.

Honda's 6-speed automatic transmission also takes some blame. Although the shifts are smooth and generally accurate, it is not as responsive as the' 8-speeder on its rivals. Therefore it is hard to engage keen drivers.

To deal with the unpleasant noise and vibration when running at 3-cylinder mode, the car employs active engine mounts, active noise cancellation system (which plays out-of-phase noise through speakers) and noise-insulating acoustic glass. They work very well in reality so that you won't feel a dramatic change of refinement during the transition.

The RLX rides on double-wishbone suspensions up front and multi-link setup at the rear. Disappointingly, it declines to offer electronic adaptive damping, which is considered a must to rival the top tier players. Instead, it employs a set of 2-stage mechanical amplitude reactive dampers by ZF-Sachs, just like the cheaper Hyundai Azera and Kia Cadenza. The front-wheel-drive chassis also put it on the negative side. To save the game, it compensates with P-AWS (Precision All-Wheel Steer) system, or what we would simply call 4-wheel steering. At low speed maneuvering, it steers the rear wheels in opposition direction to shorten turning radius. At higher speed, it steer the rear in the same direction to enhance stability. Besides, left and right rear wheels can be steered independently. For example, during braking it steers the rear wheels inward (toe-in) to keep the car stable.

Even so, the RLX is still far from good to drive. Its handling might be pretty good for a FWD, but it is less agile than the German rivals and Jaguar. Push it beyond 8/10 and you will find its body control less precise and the response to steering and throttle less sharp. It simply feels bigger and heavier. The electrical power steering feels numb on the straight ahead and always uninspiring. You might expect ride quality to be better, but again it disappoints with a bouncy ride on rough surfaces (although it works much better on smooth highways). The aggressive 245/40WR19 tires also generate too much road noise. As a result, it fails to please both the driver and the back seat passengers.

Honda has once again failed to deliver its promise in the luxury car segment. Now it can only hope the forthcoming Sport Hybrid SH-AWD version to be much much better.

Verdict:

Published on 15 Dec 2013

RLX Sport Hybrid SH-AWD

The biggest advantage of front-wheel drive is space saving. However, to a large luxury car which is not short of space, front-wheel drive could cause image problems, because it implies the car is built on a smaller platform and shares key components with cheaper siblings. This has long been the case of Honda Legend / Acura RL. The last generation Legend / RL partly avoided the problem by opting for a clever SH-AWD (Super Handling All-Wheel Drive) system, which not only provided four-wheel drive but also torque vectoring between the rear wheels. As a result, its handling was surprisingly good and the car was quite fun to drive. It is easy to imagine the new Acura RLX to adopt the same system, but to our surprise, it doesn't. While the regular RLX relies on cheap FWD, flagship model employs a radically different AWD and torque-vectoring system that combines a hybrid powertrain. The result is an even longer name, Sport Hybrid SH-AWD.

The 3.5-liter V6 is carried over from the regular car. It gets a slightly different cam profile to suit the power characteristic of hybrid, but the outcome is virtually identical, i.e. 310 horsepower and 273 pound-foot of torque. There is an electric motor mounted beside the engine. It may use its 47 hp and 109 lbft output to aid acceleration, but for most of the time it acts as a generator to recharge the 1.3 kWh lithium-ion battery. There is no mechanical linkage between the engine and the rear axle because the rear wheels are powered by a pair of electric motors. As one motor is responsible for one rear wheel, torque vectoring can be easily implemented by altering the output of individual motors. In extreme cases it may even apply regenerative braking on the inside rear wheel and positive power on the outside rear wheel, although I don't see the need of such condition in the real world. The electric torque vectoring allows it to ditch the 4-wheel steering of the FWD model.

The problem is, the rear motors are not very powerful. With a combined output of only 72 hp and 108 lbft, they can never make the RLX feeling rear-drive, unlike the old car, whose rear differential and multi-plate clutches was able to send up to 70 percent power to the rear axle or even to one rear wheel! This explains why the new car doesn't handle with the swift manner of the old car on the road. Its handling is more about smoothness and neutrality. Like the regular RLX, drive it to the 8/10 and it feels precise, confident. Push it harder and its chassis dynamic starts falling off – too much roll, too slow and numb the steering and the brakes too touchy. The suspension's softness is obvious, as is the hefty weight of 1975 kg (the hybrid system alone adds 162 kg). It simply doesn't feel as sporty as most rivals you can mention, such as Cadillac CTS, Jaguar XF, BMW 5-Series, Mercedes E-class, Audi A6 and Lexus GS. Moreover, above 78 mph the rear motors are disengaged to avoid overspinning, thus the car is reverted to FWD.

Comparatively, performance is stronger. With a combined output of 377 hp and 377 lbft, it is able to accelerate from rest to 60 mph in just over 5 seconds as if it was powered by a V8. The new 7-speed twin-clutch gearbox that it uses instead of the usual 6-speed automatic is also admirably responsive. Meanwhile, the hybrid benefit is reflected on fuel economy. EPA combined figure is lifted from the regular car's 24 to 30 mpg. If you drive a lot in urban area, the 10 percent or so price premium is worthwhile. If you drive more on highway, you may see little gain in fuel economy, just like all hybrid cars.

However, hybrid, especially a non-plug-in hybrid, is no longer special these days. I think not many people will be touched by its green pretention. Meanwhile, its average dynamics, slightly bland styling and the general perception that it is based on the Accord componentry will continue to drag its popularity. Sport Hybrid SH-AWD is a brave attempt, but it needs to do more and better.

Verdict: