The Alpina B3 Coupe (E46) 3.3 i 24V B3S, produced between 2003 and 2006, represents a unique blend of BMW engineering and Alpina’s signature refinement. Built on the E46 3 Series platform, the B3 Coupe aimed to deliver a more exclusive and performance-oriented experience than the standard BMW offerings. This particular variant, the B3S, was the higher-performance version of the B3 Coupe, boasting a naturally aspirated 3.3-liter inline-six engine producing 305 horsepower. It occupied a niche position, bridging the gap between the standard 3 Series and the more track-focused M3, appealing to drivers seeking a sophisticated grand tourer with genuine performance credentials.
Technical Specifications
| Brand | Alpina |
| Model | B3 |
| Generation | B3 Coupe (E46) |
| Type (Engine) | 3.3 i 24V B3S (305 Hp) |
| Start of production | 2003 |
| End of production | 2006 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 5 |
| Doors | 2 |
| Fuel consumption (urban) | 16.2 l/100 km (14.5 US mpg, 17.4 UK mpg, 6.2 km/l) |
| Fuel consumption (extra urban) | 7.9 l/100 km (29.8 US mpg, 35.8 UK mpg, 12.7 km/l) |
| Fuel consumption (combined) | 10.9 l/100 km (21.6 US mpg, 25.9 UK mpg, 9.2 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5.4 sec |
| Acceleration 0 – 62 mph | 5.4 sec |
| Acceleration 0 – 60 mph | 5.1 sec |
| Maximum speed | 271 km/h (168.39 mph) |
| Weight-to-power ratio | 5.3 kg/Hp, 188.3 Hp/tonne |
| Weight-to-torque ratio | 4.5 kg/Nm, 223.5 Nm/tonne |
| Power | 305 Hp @ 6300 rpm |
| Power per litre | 91.2 Hp/l |
| Torque | 362 Nm @ 4800 rpm (267 lb.-ft. @ 4800 rpm) |
| Engine layout | Front, Longitudinal |
| Engine displacement | 3346 cm3 (204.19 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 87 mm (3.43 in.) |
| Piston Stroke | 93.8 mm (3.69 in.) |
| Compression ratio | 10.2:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | DOHC |
| Kerb Weight | 1620 kg (3571.49 lbs.) |
| Max. weight | 2040 kg (4497.43 lbs.) |
| Max load | 420 kg (925.94 lbs.) |
| Trunk (boot) space – minimum | 410 l (14.48 cu. ft.) |
| Fuel tank capacity | 63 l (16.64 US gal, 13.86 UK gal) |
| Length | 4488 mm (176.69 in.) |
| Width | 1757 mm (69.17 in.) |
| Height | 1367 mm (53.82 in.) |
| Wheelbase | 2725 mm (107.28 in.) |
| Front track | 1471 mm (57.91 in.) |
| Rear (Back) track | 1472 mm (57.95 in.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, manual transmission |
| Front suspension | Wishbone |
| Rear suspension | Coil spring |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 225/40 ZR18; 255/35 ZR18 |
| Wheel rims size | 8J x 18; 9J X 18 |
Powertrain & Engine Architecture
At the heart of the B3S lies Alpina’s modified version of the BMW M54 inline-six engine. Displacing 3.3 liters, the engine benefited from a higher compression ratio (10.2:1), optimized cylinder head porting, and a bespoke exhaust system. These modifications, combined with a refined engine management system, allowed the engine to produce 305 horsepower and 362 Nm (267 lb-ft) of torque. The engine utilized a multi-port fuel injection system and a double overhead camshaft (DOHC) valvetrain, ensuring efficient combustion and strong performance across the rev range. The B3S was exclusively offered with a six-speed manual transmission, providing drivers with precise control over the engine’s power. This transmission was known for its smooth shifts and robust construction.
Driving Characteristics
The B3S offered a distinctly different driving experience compared to both the standard E46 3 Series and the M3. While the M3 prioritized outright track performance, the B3S focused on providing a more refined and usable power delivery. The 3.3-liter engine delivered strong torque from low RPMs, making it exceptionally drivable in everyday situations. The six-speed manual transmission allowed for precise gear selection, and the car felt balanced and composed in corners. Acceleration to 60 mph was achieved in approximately 5.1 seconds, and the B3S could reach a top speed of 168.39 mph. Compared to the higher-revving M3, the B3S felt more relaxed and effortless, making it an ideal choice for long-distance cruising.
Equipment & Trim Levels
The Alpina B3S came generously equipped as standard. Interior appointments included sport seats upholstered in high-quality leather, a unique Alpina steering wheel, and wood trim accents. Standard features also included automatic climate control, a premium sound system, and xenon headlights. Alpina offered a range of customization options, allowing customers to personalize their B3S with features such as a sunroof, navigation system, and upgraded audio components. The exterior was distinguished by subtle Alpina-specific styling cues, including a front spoiler, rear spoiler, and unique alloy wheels.
Chassis & Braking
The B3S featured a modified suspension system designed to enhance both handling and ride comfort. Alpina utilized stiffer springs and dampers, along with thicker stabilizer bars, to reduce body roll and improve cornering stability. The braking system consisted of ventilated discs on all four wheels, providing ample stopping power. The ABS (Anti-lock braking system) ensured safe and controlled braking in various conditions. The chassis was reinforced in key areas to handle the increased power and torque of the engine.
Market Reception & Comparison
The Alpina B3S was well-received by automotive critics, who praised its blend of performance, refinement, and exclusivity. It was often seen as a compelling alternative to the BMW M3, offering a more comfortable and luxurious driving experience. Fuel economy, while not a primary focus, was respectable for a high-performance coupe, averaging around 21.6 US mpg in combined driving. Compared to the standard 3 Series models, the B3S offered significantly improved performance and handling. Reliability was generally good, although maintenance costs were higher due to the specialized nature of the Alpina components.
Legacy
Today, the Alpina B3 Coupe (E46) 3.3 i 24V B3S is considered a desirable and collectible car. Its limited production numbers and unique character have made it a favorite among enthusiasts. The 3.3-liter engine is known for its durability and relatively straightforward maintenance. While finding parts can sometimes be challenging due to the car’s rarity, a dedicated community of Alpina owners and specialists exists to provide support and expertise. The B3S represents a high point in Alpina’s history, showcasing the company’s ability to create truly special and engaging automobiles.
