The ultimate driving machine in a two-door GT.

Introduction

The BMW 6 Series delivers stellar performance, brilliant handling, and that arrow-like stability that marks this marque. The 6 Series is a true grand touring car, unique in the BMW line-up. And it comes in coupe and convertible styles. 

The 645Ci coupe and 645Ci convertible are essentially hard top and soft top versions of the same car. Bristling with the latest in technology, they are based on the superb new 5 Series chassis but are not simply two-door versions of the sedans. The 6 Series cars are modern GTs, or Gran Turismo cars. They offer greater luxury and comfort than the Z4 sports car, yet with higher performance, more agile handling, and sportier styling than the 5 Series sports sedans. 

The 645Ci Coupe and 645Ci Convertible each qualify as an ultimate driving machine, yet either can be driven all day in perfect comfort. 

Lineup

The BMW 645Ci Coupe ($69,900) and 645Ci Convertible ($76,900) are nearly identical in temperament and equipment. Leather upholstery, a choice of rich interior trim, and a long list of luxury features are standard, including a sports suspension, 18-inch wheels, xenon adaptive headlamps, and park-assist. 

BMW's 4.4-liter V8 powers the 645Ci models, delivering 325 horsepower to the rear wheels. A choice of transmissions includes a six-speed manual gearbox (standard), a six-speed automatic with Steptronic (a no-cost option), and a six-speed sequential manual gearbox ($1,300). 

Options include Sirius Satellite Radio ($670); heated front seats ($500); active cruise control ($2,200); head-up display ($1,000). The Sport Package ($2,800) adds active steering, 19-inch sport wheels with run-flat tires, and sport seats. A Premium Sound Package ($1,800) includes Logic7 audio with six-disc CD changer. A Cold Weather Package ($750) includes heated front seats, a heated steering wheel, and a ski bag. 

Walkaround

The twin-kidney grille, quad headlamps and other classic cues identify the 6 Series cars as BMWs. The 6 Series shares some key elements with the new 5 Series sedan, but it was designed from the ground up as a coupe rather than a sedan with two doors lopped off. 

It's a classic BMW coupe: The front and rear overhangs (the distance from the wheels to the bumper) are short. The windshield is set back from the hood. The 6 Series cars are shorter in overall length than the 5 Series sedans, but benefit from a relatively long wheelbase (the distance between the front and rear wheels). In short, you know these cars handle great just by looking at them. 

The turn signals are located above the headlamps allowing the headlamps to be moved farther around the corners to the sides of the car. The grilles take front and center stage with no bumper ledge in front of them. When viewed from overhead, the front corners look rounded giving the 6 Series a shark nose. 

In profile, the lines are sculpted but clean. Side marker lights at the trailing edge of the front wheel wells give the impression of attention to detail. 

From the rear, however, the 6 Series cannot be identified as readily. The tail lamps and badge label it as a BMW, but the rear looks different from past BMWs. The tail lamps wrap around to the sides, so there's no precise point where the rear of the car ends and the side begins. As with the new 7 Series cars, critics don't like the way the rear deck looks somewhat disconnected from the rear fenders. BMW points out that the high deck improves rear grip at high speeds and allows for a big trunk. In any case this is a tidy, attractive car that looks sporty. It looks best in silver and other lighter colors; the design details blend together on darker cars. 

When the top is up, the roofline of the convertible is nearly identical to that of the coupe. The soft top looks great, featuring a fastback roofline with fins on the trailing edges that frame the vertically mounted glass backlight (rear windscreen); the rear glass can be raised or lowered like a side window by pressing a button. Replacing a steel roof with a convertible top tends to reduce chassis rigidity, so BMW says reinforced the B-pillar and the lower sides of the monocoque. 

The 6 Series comes standard with adaptive headlamps that aim toward the inside of a corner as the steering wheel is turned. This helps throw light around bend when cornering, reducing shadows and improving visibility for the driver. Sometimes just that extra moment of warning can make for a safer and more enjoyable drive. 

The BMW 6 Series coupe and convertible are comfortable cars that encourage the driver to take the joy of driving seriously. The seats are comfortable and supportive, more comfortable than the ultra-firm seats found in some of BMW's sports packages. You feel safely ensconced in this car, partly because of its high waistline. 

The iDrive system features a big knob mounted on the center console that controls navigation, the audio system, climate controls, and other secondary functions. Various functions can be selected by sliding the big knob left or right, forward or aft, then turning it like a knob to work through menus displayed on a monitor on the center stack, and pressing down on the knob to select options. The big knob doesn't move diagonally as in the 7 Series cars, which may simplify things, but we recommend sitting in the driveway with the owner's manual to master this system. 

The head-up display projects speed, navigational information, cruise control status and other data onto the windshield. 

The trunk is relatively large and can hold two sets of golf clubs. The BMW badge on the rear serves as the latch for the trunk. The trunk lid pops open fully when the button on the remote key fob is pressed, handy when running through the rain with an armload of groceries; a lot of trunk lids don't pop up like this, an advantage of goosenec. 

Interior

The BMW 6 Series coupe and convertible are comfortable cars that encourage the driver to take the joy of driving seriously. The seats are comfortable and supportive, more comfortable than the ultra-firm seats found in some of BMW's sports packages. You feel safely ensconced in this car, partly because of its high waistline. 

The iDrive system features a big knob mounted on the center console that controls navigation, the audio system, climate controls, and other secondary functions. Various functions can be selected by sliding the big knob left or right, forward or aft, then turning it like a knob to work through menus displayed on a monitor on the center stack, and pressing down on the knob to select options. The big knob doesn't move diagonally as in the 7 Series cars, which may simplify things, but we recommend sitting in the driveway with the owner's manual to master this system. 

The head-up display projects speed, navigational information, cruise control status and other data onto the windshield. 

The trunk is relatively large and can hold two sets of golf clubs. The BMW badge on the rear serves as the latch for the trunk. The trunk lid pops open fully when the button on the remote key fob is pressed, handy when running through the rain with an armload of groceries; a lot of trunk lids don't pop up like this, an advantage of gooseneck hinges; the hinges are shielded from the inside cargo bay, eliminating concerns of crushing things. The coupe has a larger trunk (13 cubic feet) than the convertible (12.4 cubic feet). 

The convertible is remarkably quiet with the top up, nearly as quiet as the coupe. As mentioned, the power rear windscreen can be lowered even when the top is up, though we didn't find it significantly added to air circulation. Conversely, the rear glass can be raised when the top is down to act as a windblocker, but turbulance with the top down was minimal, and raising and lowering the glass didn't seem to make a big difference. In short, this is a neat feature but one of dubious merit. 

Driving Impression

The BMW 645Ci is smooth and precise. Always poised, it is easy to drive smoothly and quickly. The ride is taut but not harsh. The engine is silky smooth and tractable for easy going around town or in stop-and-go traffic. Yet you're rewarded with immediate response whenever you press down on the accelerator. This car immediately becomes an extension of the driver, smoothly and flawlessly executing his or her wishes. It's easy to modulate the brakes and throttle and the steering is very precise, all making for a smooth driving experience. 

BMW's 4.4-liter V8 delivers 325 horsepower and 330 pound-feet of torque. The 3,781-pound coupe with the manual or SMG can accelerate from 0 to 60 mph in 5.5 seconds, according to BMW. The convertible is heavier and about a half-second slower. The 32-valve V8 benefits from Valvetronic variable valve timing and variable lift; breathing is controlled entirely by the valves. (Technically, there is no throttle, so the pedal on the right is more accurately called an accelerator.) It's a fascinating engine for engineers and car buffs with technological marvels such as its Double VANOS steplessly variable intake- and exhaust-valve timing. But the bottom line is that there's lots of power throughout the rev range, so the 645Ci responds quickly and precisely in any situation. It's also an efficient engine, so energy is not wasted but is instead channeled into fuel-efficient power. The engine sounds great, emitting a guttural roar under hard acceleration through its nicely tuned exhaust system. 

Of the three transmissions available, we recommend the six-speed automatic unless you're a serious enthusiast, in which case we recommend the six-speed manual. The automatic is smooth in normal driving and very responsive for spirited driving. In fact, a 645Ci with the automatic is nearly as quick as a well-driven 645Ci with the manual. As with all BMW automatics, it offers a Sport mode setting that moves shift points to higher revs for increased response; the Steptronic manual mode enables the driver to shift manually, imparting some of the sportiness of a manual. We found little need to shift into the manual mode, however, because it always selected the right gear in automatic mode. The manual gearbox is smooth and precise, easy to shift, with easy clutch pedal effort; it's lighter than the six-speed used in the BMW M3. In short, the six-speed manual is an excellent choice. The sequential manual gearbox, or SMG, is the same transmission as the manual, but it operates the clutch electronically, eliminating the clutch pedal. Though I like the SMG in the M3, I found the 645Ci's SMG shifted too slowly and took some of the enjoyment out of driving it; it lacks the degree of adjustability of the M3. I did not care for the SMG. 

The 645Ci offers a nice balance of ride and handling. Though taut, it doesn't beat up your passenger on rippled highways. The springs and shocks are firmer than on the 545i, but not as firm as those on the 545i sport package, which are quite firm. The 6 Series cars ride lower than the 5 Series. A 645Ci is absolutely joyful on a winding road, as we discovered on some mountain roads near Santa Barbara. Handling is precise, with a superb self-centering feel to the steering. It goes around high-speed turns like it's on rails. It can be driven very hard into tight corners. The suspension is tuned to minimize undesirable behavior when braking hard, accelerating hard, or lifting off the gas while cornering. 

Active Roll Stabilization dramatically reduces body roll in cornering. As the car turns corners, the anti-roll bars are twisted by little hydraulic motors, so the 645Ci leans very little, even in hard cornering. In addition to increasing driver confidence, the system improves handling over bumps, increases cornering capability, and improves steering response. 

Drive the 645Ci past the limit of the tires and the Dynamic Stability Control and ot. 

Summary

The BMW 6 Series coupe and convertible are comfortable and sporty. Driving these cars is a joy. The offer excellent handling and are supremely stable. The come with the latest in active safety features. The biggest decision is choosing between the coupe and the convertible. 

New Car Test Drive editor Mitch McCullough filed this report from Beverly Hills. 

Model Lineup

BMW 645Ci Coupe ($69,900); 645Ci Convertible ($76,900). 

Options As Tested

Steptronic 6-speed automatic (no charge); Sport Package ($2,800) includes active steering, sport seats, 19-inch sport wheels w performance run-flat tires.