BMW Debuts New R6 3.0L I-6 Powerplant in European-Only 630 Ci

New 6-Cylinder to Power 3, 5, X3, X5, Z4 and More Future BMWs

Of the seventy-five years that BMW has been making motor vehicles, seventy-one of them have been spent perfecting the inline-six motor. Remaking venerable powerplant is serious business, especially considering its the base formula for power of nearly every BMW car made, large or small.

With 1.4 million inline sixes built, BMWs silky-smooth six is the real driving force behind the company. The proof is also in the awards and trophies that have been won over the years. For 2005, BMW will be offering a new generation of its top-line 3.0-liter inline-six, dubbed the R6. It will carry the legendary tradition built up from past 6-cylinder engines.

Nearly every historical BMW ever produced carries the inline-six engine, but for a handful. Highlights of cars that featured the famed straight six include BMWs first six-cylinder car, the Type 303 with a 1.3- liter version. Some of the most graceful cars built incorporated the engine configuration, including the 328 of the late 30s, the elegant open-topped Type 335 and the CS-series touring coupes (which also spawned the 3.0 CSL Batmobile). Even more exotic sports cars, such as BMWs only mid-engined M1, which pioneered four-valve per cylinder engine technology and also was the basis for forming the M-division, as well as the unique Z1, a stylish roadster with unique drop-down side doors, featured the engine in various highly-tuned guises. The worlds ultimate sports sedan, the M5, started out with a straight six that seemed to get bigger and better as the years went by (the 90 version was a 3.6 liter growing to 3.8 liters in 1992). Todays hot-rod M3 incorporates a high-revving straight six at the top of its class in performance.

The current top inline-six motor in non-M cars is a 3.0-liter unit codenamed the M54. The 225 horsepower powerplant with 214 lb-ft of torque (231 and 221 respectively in Europe) features Double-Vanos (BMWs version of variable valve timing), which helps to increase overall output while reducing consumption and emissions from its 2.8 liter M52 predecessor. The awards and accolades that the M54 has picked up are enough to crown it a heavyweight, but for the fact it weighs just 377 pounds its one of the worlds lightest six-cylinder engines.

Powering the 330, 530, X3 3.0, X5 3.0 and Z4 3.0, the engines flexibility is clearly demonstrated in the variety of its applications. BMWs reputation for creating engines that are powerful, yet refined and economical puts great pressure on the engineers in charge of designing a replacement. Their research and development has paid off, or so it seems on paper at least.

Enter the R6, which will one-up the M54 at least as authoritatively as the current engine improved on the M52. Rather than calling the R6 a completely new design, BMW refers to it as a redesign. The object was to make it stronger, lighter and more powerful. Addressing the demand for more power, important being that the current M54 lacks punch when stacked up against new competitors from Acura and Infiniti, plus Mercedes-Benz new 3.5-liter V6, the most significant modification is the adaptation of Valvetronic to the M54s design. Already available in four-, eight-, and twelve-cylinder motors across the engine range, it is only logical that its application in a six-cylinder would be next. Valvetronic removes the butterfly valves which control the throttle, replacing them with an electronic motor, gears and rocker arms synchronized to alter valve lift, controlling the amount of air that enters the engine. The addition of Valvetronic has upped the engines redline by 500 rpm to 7,000, while helping to raise power outputs and flattened the torque curve. The new engine posts an increase of 27 horsepower to a total of 258 maximized at 6,650 rpm, while 221 lb-ft of torque is accessible between 2,500 and 4,000 rpm, rather than the peak of 3,500 in the M54.

While the addition of Valvetronic components would increase the engines weight, a no-no in BMWs books, leaving Valvetronic out would remove optimal improvements on engine performance and fuel consumption. BMW had to make it a mandatory component to the engine upgrade. To compensate for the additional kilos of the Valvetronic system, BMW subtracted weight by casting the crank-case, bedplate and cylinder head cover from magnesium. In comparison to other metals such as cast-iron, steel or aluminum, each commonly used for constructing engine blocks and components, magnesium is highly coveted for its superior strength and even lighter weight. The R6 is one of the first mass-production motors to make use of this metal, showing that BMW doesnt cut corners when developing its motors.

Other measures, such as a magnesium-aluminum camshaft thats 21.2 ounces lighter than parts made from conventional metals -- 2.6 pound savings in a DOHC motor -- helps to create a lighter engine. The extent of the magnesium-rich diet has resulted in 22.0 pounds, or 7 percent of the total engines weight being shed.

BMWs, like most other German cars sold in North America, are considered premium performance vehicles. Such arent usually friendly on the wallet when it comes to filling up at the pump. Valvetronic, as well as several other fuel-saving technologies, will cut down on the inline-sixs thirst for liquid gold.

An electric water pump (a worlds first), a single belt that drives all ancillary components, and a capacity controlled oil pump, all help to cut back on excessive energy use. Alone, the Valvetronic system has shown a 10 percent decrease in fuel consumption, meaning all other energy-saving components only add to the positive results. Actual fuel consumption figures are dependant on the car that this motor is fitted to. An X5, for instance, uses much more gasoline than a Z4 because of its greater curb weight and higher wind resistance, so its best to wait for actual figures. Expect a 1 to 2 mpg improvement at the very least.

Like the M54, the R6 will be used in a wide variety of vehicles. As of right now, however, the only confirmed vehicle to make use of it is the recently introduced 630 Ci grand touring coupe (not available in North America). Expect to see the 5-Series and X5 adopt the R6 in the near future, as well as the 3-Series, X3 and Z4 in the next year or so.

Many of the engines advanced technologies, particularly the use of magnesium and Valvetronic, make a person wonder if BMW plans to upgrade its lesser straight six motors. Currently, BMW has two other gasoline-powered inline sixes, an entry-level 2.2 liter unit which generates 168 horsepower (170 in Europe) and 155 lb-ft of torque, and a mid-level 2.5-liter six that makes 184 horsepower and 175 lb-ft of torque (192 and 181 respectively in Europe). As of right now, BMW holds the benchmark for the finest six-cylinder motor of its type, and with the completion of the R6 it will be in the top spot for years to come.