MILLVILLE, NJ – For more than a decade, only two cars have really mattered to performance-minded buyers in Ward’s midsize luxury car segment: the BMW 5-Series and Mercedes E-Class.

With good reason. These German premium sedans have balanced executive-suite tranquility with world-class engines and chassis control for occasional dynamic driving.

Throughout the 1990s, the luxury-oriented Lincoln Town Car and Cadillac DeVille ruled the segment, often selling more than 100,000 units annually.

The days of those volume levels are long gone for luxury brands struggling to convince cash-strapped consumers that vehicles costing more than $50,000 are worth it.

The best-selling 5-Series and E-Class each have mustered about 50,000 deliveries annually the past several years. Lagging far behind were marginal entries such as the Lexus GS, Cadillac STS, Volvo S80, Audi A6 and Infiniti M.

Today, the E-Class is pummeling the 5-Series, causing a bad case of Bavarian heartburn.

The new E-Class sedan arrived last year about the same time BMW was building out the previous-generation 5-Series in preparation for this year’s launch of the all-new 5. A sleek redesigned E-Class convertible coming this spring should help Mercedes extend its lead in the short term.

But BMW AG knows this market well, and its executives are reasonably confident the all-new’11 5-Series, going on sale this month in the U.S., will turn the tide on Mercedes, perfectly timed to capitalize on an improving economy.

The new sport sedan provides the proof necessary to support the argument.

Two new direct-injection gasoline engines (in the 535i and 550i) deliver more power as well as better fuel efficiency. Chassis dynamics are solid, considering a weight gain of about 400 lbs. (181 kg).

And the addition of new technologies such as automated parking, collision warning, adaptive cruise control, night vision and regenerative braking enhance the value equation.

On the downside, the sixth-generation 5-Series doesn’t look all that new. The car is bigger (and the wheelbase 3.2 ins. [8.1 cm] longer), but the overall shape basically is unchanged. Creases in the stamped aluminum hood, doors and front fenders add subtle flair, and shorter overhangs contribute to an athletic stance.

Inside, the interior could be mistaken for that of the 7-Series flagship, with which the new 5-Series shares architectural underpinnings and extensive componentry. The plant in Dingolfing, Germany, produces both 7-Series and 5-Series.

Clearly, BMW was happy with the previous car and saw little need for a clean-sheet redesign. The sheet already was pretty clean to begin with.

Perhaps the iterative styling is intended to pre-empt the type of hue and cry that greeted the radical redesign of the previous-generation 7-Series and 5-Series penned by controversial former design chief Chris Bangle. In the end, strong sales proved BMW better understood the market than critics.

BMW doesn’t care much for beauty pageants anyway. Instead, the auto maker prefers to dazzle buyers with keen engineering and smart technology as building blocks for supreme drivability.

As with many BMWs, the most compelling story line is underhood.

The 550i adds the excellent 4.4L DOHC twin-turbo V-8 that also powers the 7-Series, the 5-Series Gran Turismo and X6 and X5 cross/utility vehicles. The “reverse-flow” engine (codename N63) delivers an extra 40 hp and 90 lb.-ft. (122 Nm) of torque when compared with the naturally aspirated 4.8L V-8 it replaces.

The new 4.4L sprints to 60 mph (97 km/h) in 5 seconds, a half-second faster than the previous V-8, and its combined EPA fuel-efficiency rating of 20 mpg (11.7 L/100 km) is 11% better than the old engine.

’11 BMW 535i
Vehicle type Front-engine, rear-drive, 5-passenger, 4-door sedan
Engine 3.0L turbocharged DOHC all-aluminum I-6
Power (SAE net) 300 hp @ 5,800-6,250 rpm
Torque 300 lb.-ft. (407 Nm) @ 1,200-5,000rpm
Transmission 6-speed manual
Wheelbase 116.9 ins. (297 cm)
Overall length 193.1 ins. (490 cm)
Overall width 73.2 ins. (186 cm)
Overall height 57.6 ins. (146 cm)
Curb weight 4,056 lbs./1,840 kg
Base price $50,475
Competition Audi A6; Mercedes E-Class; Lexus GS; Infiniti M; Volvo S80; Cadillac CTS; Jaguar XF
Pros Cons
Fabulous engines Must wait for diesel
Proven chassis dynamics Could lose 400 lbs.
7-Series interior clone 7-Series interior clone

But the volume engine likely will be the 535i’s turbocharged inline 6-cyl., which has been modified for maximum mileage.

This engine (codenamed N55) will seem very familiar to BMW aficionados, producing 300 hp and 300 lb.-ft. (407 Nm) of torque. That output is identical to the previous-generation N54 I-6, which deployed a more complex induction strategy requiring two separate turbochargers. It earned three straight Ward’s 10 Best Engines awards from 2007 to 2009.

The N55 engine, instead, uses a twin-scroll unit in one housing, which allows the torque peak to arrive earlier, at 1,200 rpm, compared with 1,400 rpm for the N54.

With the new induction strategy and a fully variable third-generation Valvetronic throttleless intake, the new N55 earns the 535i a combined EPA rating of 23 mpg (10.2 L/100 km), 15% better than the N54 in the much lighter previous-generation 5-Series.

A drive of the 535i here confirms the EPA’s mileage rating, despite spirited runs to the red line. Plentiful low-end grunt dismisses the concern that eliminating one of the turbochargers would result in turbo lag in a sedan this size. Like the N54, the modified engine still sounds glorious.

The 535i and 550i go on sale in June, followed a month later by the 528i, which is powered by a naturally aspirated 240-hp I-6 and available only with an automatic transmission. All-wheel-drive versions also are on tap, and a diesel offering is expected as well.

Six-speed manual gearboxes are available in both the 535i and 550i, but the all-new 8-speed automatic from ZF Friedrichshafen AG gets better fuel economy with its taller cruising gears and delivers crisp shifting. BMW expects a 10% manual take-rate for the 550i and about 6% for the 3-pedal 535i.

The new automatic transmission’s two additional ratios for gears 7 and 8 bring no additional weight. Five clutch packs are controlled so no more than two of them are freewheeling at any given time.

Combined with reduced friction and the ability to keep the torque converter “locked up” more of the total driving time, the new transmission contributes much to overall fuel economy, while enabling an attention-grabbing 8-2 gear shift.

A new multi-link front suspension incorporates upper lateral A-arms (in place of the conventional struts) and double-pivot lower arms.

Similar to that employed in the 7-Series and X5, the mostly aluminum setup reduces friction, frees up space for larger brakes and delivers straight-line stability and excellent steering return coming out of curves.

BMW says its “Integral” rear suspension, also a multi-link arrangement, precisely controls rear-wheel geometry for a comfortable, supple ride.

Another fuel-saver, electric power steering, appears for the first time in a BMW sedan in the U.S. and consumes no energy when driving straight.

Steering feel is natural, responsive and firm, without being over-assisted – a criticism of some previous EPS systems. BMW consistently represents the benchmark for steering feel, so consider the 5-Series application a coup for this emerging technology.

The heavier 5-Series Gran Turismo still uses hydraulic steering.

Also available as an option is Integral Active Steering, which turns rear wheels slightly parallel to the front wheels during high-speed lane changes. In low-speed curves and U-turns, the rear wheels move in the opposite direction, improving maneuverability and reducing the turning circle.

Inside, the steering wheel is new to the 5-Series but identical to that of the 7-Series. The two vehicles also have similar instrument panels, the same switchgear and the same placement of vents and controls.

Not that there’s anything wrong with emulating the 7-Series. But it raises the question as to whether a younger demographic for the 5-Series wants something more sporty.

BMW design executives are proud of two unique creases in the IP above the glove box. They may consider it an important styling achievement, but to paying customers, the change will be barely noticeable.

These are minor quibbles about an interior that is beautifully appointed and comfortable. Sure, BMW interiors all are starting to look the same, but why mess with success?

The auto maker has sold 5.5 million 5-Series cars worldwide over the course of five generations, and its knowledge of the luxury market is hard to question.

Pricing starts at $45,425 for the 528i, $50,475 for the 535i and $60,575 for the 550i. A sport package with 19-in. wheels adds $2,200; a premium package with navigation, satellite radio, rear-view camera and premium audio adds $4,900; and an active ventilated seat package adds $2,950.

Although the 5-Series makes up 20% of the brand’s volume, it consistently generates 40% of the profits.

A phone is ringing at Mercedes’ headquarters in Stuttgart. BMW is on the line and wants its crown back in the midsize luxury segment.

tmurphy@wardsauto.com