The BMW 6 Series Convertible (E64) 630i Steptronic, produced from 2004 to 2007, represented a significant entry point into BMW’s luxury convertible range. Positioned within the E64 generation – which spanned from 2004 to 2010 – the 630i offered a blend of performance and comfort, appealing to buyers seeking a sophisticated open-top experience without the higher price tag of the 645Ci or 650i models. It was a key component of BMW’s strategy to broaden the appeal of the 6 Series, competing with rivals like the Mercedes-Benz CLK-Class and Audi A4 Cabriolet in the premium convertible segment.
Technical Specifications
| Brand | BMW |
| Model | 6 Series |
| Generation | 6 Series Convertible (E64) |
| Type (Engine) | 630i (258 Hp) Steptronic |
| Start of production | 2004 |
| End of production | 2007 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 14.2 l/100 km (16.6 US mpg, 19.9 UK mpg, 7 km/l) |
| Fuel consumption (extra urban) | 7.5 l/100 km (31.4 US mpg, 37.7 UK mpg, 13.3 km/l) |
| Fuel consumption (combined) | 9.9 l/100 km (23.8 US mpg, 28.5 UK mpg, 10.1 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 7.2 sec |
| Acceleration 0 – 62 mph | 7.2 sec |
| Acceleration 0 – 60 mph | 6.8 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 6.6 kg/Hp, 151.8 Hp/tonne |
| Weight-to-torque ratio | 5.7 kg/Nm, 176.5 Nm/tonne |
| Power | 258 Hp @ 6600 rpm |
| Power per litre | 86.1 Hp/l |
| Torque | 300 Nm @ 2500 rpm (221.27 lb.-ft. @ 2500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | N52B30A |
| Engine displacement | 2996 cm3 (182.83 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 85 mm (3.35 in.) |
| Piston Stroke | 88 mm (3.46 in.) |
| Compression ratio | 10.7:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | DOHC |
| Engine oil capacity | 6.5 l (6.87 US qt | 5.72 UK qt) |
| Kerb Weight | 1700 kg (3747.86 lbs.) |
| Max. weight | 2100 kg (4629.71 lbs.) |
| Max load | 400 kg (881.85 lbs.) |
| Trunk (boot) space – minimum | 300 l (10.59 cu. ft.) |
| Trunk (boot) space – maximum | 350 l (12.36 cu. ft.) |
| Fuel tank capacity | 70 l (18.49 US gal | 15.4 UK gal) |
| Length | 4820 mm (189.76 in.) |
| Width | 1855 mm (73.03 in.) |
| Height | 1373 mm (54.06 in.) |
| Wheelbase | 2780 mm (109.45 in.) |
| Front track | 1558 mm (61.34 in.) |
| Rear (Back) track | 1596 mm (62.83 in.) |
| Drag coefficient (Cd) | 0.31 |
| Minimum turning circle | 11.4 m (37.4 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears | 6 |
| Gearbox type | Automatic transmission |
| Front suspension | Coil spring |
| Rear suspension | Coil spring |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Hydraulic Steering |
| Tires size | 245/40 R17 |
| Wheel rims size | 17 |
Powertrain & Engine Architecture
The 630i Steptronic was powered by BMW’s N52B30A engine, a 3.0-liter inline-six cylinder naturally aspirated powerplant. This engine was a cornerstone of BMW’s mid-2000s lineup, known for its smooth power delivery and relatively high efficiency. The N52 featured double overhead camshafts (DOHC), four valves per cylinder, and BMW’s VANOS variable valve timing system on both intake and exhaust camshafts. This allowed for optimized performance across the rev range. Fuel was delivered via multi-port fuel injection. The engine produced 258 horsepower at 6600 rpm and 300 Nm (221 lb-ft) of torque at 2500 rpm. The “Steptronic” designation indicated the use of BMW’s six-speed automatic transmission, which offered both fully automatic operation and a manual shift mode. This transmission was designed to provide smooth gear changes and contribute to the car’s overall refinement.
Driving Characteristics
The 630i Steptronic offered a comfortable and refined driving experience. While not as overtly sporty as the 645Ci or 650i, the 3.0-liter engine provided ample power for everyday driving and cruising. The automatic transmission, while smooth, did slightly diminish the sense of connection to the car compared to the available six-speed manual. Acceleration from 0 to 60 mph took approximately 6.8 seconds, and the car had a top speed of 155 mph. The gear ratios were tuned for a balance of fuel economy and responsiveness, with a focus on providing effortless cruising at highway speeds. Compared to the higher-output models, the 630i felt less urgent in its acceleration, but it offered a more relaxed and accessible driving experience.
Equipment & Trim Levels
The 630i Steptronic came standard with a generous array of features, befitting its luxury positioning. Standard equipment included leather upholstery, power-adjustable front seats with memory function, automatic climate control, a premium sound system, and BMW’s iDrive infotainment system. Optional extras included features like active steering, sport seats, upgraded leather trim, a navigation system, and a logic7 surround sound system. The convertible top was fully automatic and could be raised or lowered in around 20 seconds. Trim levels were relatively simple, with most customization occurring through the selection of optional packages and individual options.
Chassis & Braking
The E64 6 Series Convertible featured a robust chassis designed to provide both rigidity and a comfortable ride. The suspension utilized coil springs and shock absorbers all around. The front suspension employed a MacPherson strut design, while the rear suspension used a multi-link setup. The 630i was equipped with ventilated disc brakes at the front and solid disc brakes at the rear. Anti-lock braking system (ABS) was standard. The steering was a rack-and-pinion system with hydraulic power assistance. The car rode on 17-inch alloy wheels with 245/40 R17 tires.
Market Reception & Comparison
The 630i Steptronic was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and smooth engine. However, some reviewers noted that the automatic transmission could feel a bit sluggish at times, and that the car lacked the outright performance of its more powerful siblings. Fuel economy was considered reasonable for a luxury convertible, averaging around 23.8 mpg in combined driving. Compared to the 645Ci, the 630i offered a more affordable entry point into the 6 Series range, but at the expense of some performance. Compared to the 650i, the difference in power and prestige was even more significant.
Legacy
The BMW E64 630i Steptronic has proven to be a relatively reliable vehicle, with the N52 engine being known for its durability. Common maintenance items include oil changes, coolant flushes, and spark plug replacements. The automatic transmission is generally reliable, but regular fluid changes are essential. Today, the E64 630i represents an affordable way to experience BMW’s luxury convertible heritage. While not as sought-after as the higher-performance models, it remains a stylish and capable grand tourer, offering a blend of comfort, performance, and open-air enjoyment.
