The BMW 728i, produced between 1979 and 1983, was a pivotal model within the first generation (E23) of the BMW 7 Series. Positioned as the entry-level offering in the 7 Series lineup, it aimed to deliver a luxurious driving experience at a more accessible price point than its larger-engined siblings, the 730i and the flagship 733i/735i. The 728i represented BMW’s attempt to broaden the appeal of its flagship sedan, offering a blend of performance and comfort that appealed to a wider range of buyers. It was a significant vehicle in establishing the 7 Series as a benchmark for luxury automobiles.
Technical Specifications
| Brand | BMW |
| Model | 7 Series |
| Generation | 7 Series (E23) |
| Type (Engine) | 728i (184 Hp) Automatic |
| Start of production | 1979 |
| End of production | 1983 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 14.5 l/100 km (16.2 US mpg, 19.5 UK mpg, 6.9 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 11.5 sec |
| Acceleration 0 – 62 mph | 11.5 sec |
| Acceleration 0 – 60 mph | 10.9 sec |
| Maximum speed | 190 km/h (118.06 mph) |
| Weight-to-power ratio | 8.2 kg/Hp, 122.3 Hp/tonne |
| Weight-to-torque ratio | 6.4 kg/Nm, 156.1 Nm/tonne |
| Power | 184 Hp @ 5800 rpm |
| Power per litre | 66 Hp/l |
| Torque | 235 Nm @ 4300 rpm (173.33 lb.-ft. @ 4300 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | 286EZ1 |
| Engine displacement | 2788 cm3 (170.13 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 86 mm (3.39 in.) |
| Piston Stroke | 80 mm (3.15 in.) |
| Compression ratio | 9.3:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | SOHC |
| Engine oil capacity | 5.8 l (6.13 US qt | 5.1 UK qt) |
| Coolant | 12 l (12.68 US qt | 10.56 UK qt) |
| Kerb Weight | 1505 kg (3317.96 lbs.) |
| Max. weight | 1960 kg (4321.06 lbs.) |
| Max load | 455 kg (1003.1 lbs.) |
| Fuel tank capacity | 100 l (26.42 US gal | 22 UK gal) |
| Length | 4860 mm (191.34 in.) |
| Width | 1800 mm (70.87 in.) |
| Height | 1430 mm (56.3 in.) |
| Wheelbase | 2795 mm (110.04 in.) |
| Front track | 1502 mm (59.13 in.) |
| Rear track | 1524 mm (60 in.) |
| Ride height (ground clearance) | 132 mm (5.2 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears and type of gearbox | 3 gears, automatic transmission |
| Front suspension | Independent, type McPherson with coil spring and anti-roll bar |
| Rear suspension | Independent coil spring |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Tires size | 195/70 HR14; 220/55 HR390 TRX |
| Wheel rims size | 6.0J x 14; 165 T 390 |
Powertrain & Engine Architecture
The heart of the 728i was the M286 engine, a 2.8-liter inline-six cylinder powerplant. Designated as the 286EZ1, this engine featured a single overhead camshaft (SOHC) valvetrain operating two valves per cylinder. It utilized Bosch L-Jetronic multi-port fuel injection, a relatively advanced system for the time, contributing to improved fuel efficiency and smoother operation compared to carbureted engines. The engine produced 184 horsepower at 5800 rpm and 235 Nm (173 lb-ft) of torque at 4300 rpm. The engine’s longitudinal mounting and rear-wheel-drive configuration were standard for BMW at the time. Paired with the engine was a 3-speed automatic transmission, offering a comfortable, albeit not particularly sporty, driving experience. This automatic was a key differentiator, targeting buyers who prioritized ease of use over outright performance.
Driving Characteristics
The 728i Automatic offered a comfortable and refined driving experience, but it wasn’t known for its blistering acceleration. The 0-60 mph time of around 10.9 seconds reflects this. Compared to the manual transmission versions of the 728i, the automatic resulted in a slight performance decrease due to the inherent power losses within the torque converter. The 3-speed automatic’s gear ratios were geared towards cruising comfort rather than aggressive acceleration. Compared to the more powerful 733i and 735i models, the 728i felt noticeably less responsive, particularly when overtaking. However, the automatic transmission provided a smooth and effortless driving experience, making it well-suited for city driving and long highway journeys.
Equipment & Trim Levels
The 728i, even as the entry-level 7 Series, was well-equipped for its time. Standard features typically included power windows, central locking, air conditioning, and a high-quality sound system. Interior upholstery was generally cloth, although leather was available as an option. The dashboard layout was typical of BMW in the late 1970s and early 1980s, featuring a driver-focused design with clearly marked gauges. Optional extras included a sunroof, upgraded sound systems, and more luxurious leather upholstery. The trim level was generally consistent, with variations primarily stemming from the addition of optional packages.
Chassis & Braking
The E23 7 Series featured an independent suspension system all around. The front suspension utilized a McPherson strut design with coil springs and an anti-roll bar, while the rear suspension employed a semi-trailing arm setup with coil springs. The 728i typically came equipped with ventilated disc brakes at the front and solid disc brakes at the rear. The braking system provided adequate stopping power for the car’s weight and performance. The suspension tuning was geared towards providing a comfortable ride, prioritizing smoothness over sharp handling. Stabilizer bars were fitted to both axles to reduce body roll during cornering.
Market Reception & Comparison
The 728i Automatic received mixed reviews. Critics generally praised its comfort, refinement, and build quality, but some found its performance underwhelming, especially compared to the more powerful 7 Series models. Fuel economy was also a concern, with the 2.8-liter engine consuming a significant amount of fuel for its output (around 16.2 US mpg in urban driving). Compared to the 730i and 733i/735i, the 728i offered a more affordable entry point into the 7 Series range, but at the cost of performance. The 728i was often seen as a good choice for buyers who prioritized comfort and luxury over outright speed.
Legacy
The BMW E23 728i, while not the most sought-after variant of the first-generation 7 Series, holds a significant place in BMW’s history. The M286 engine proved to be relatively reliable, and well-maintained examples continue to be driven today. The automatic transmission, while not known for its sportiness, has also proven durable. In the used car market, the 728i is generally more affordable than its higher-powered siblings, making it an attractive option for enthusiasts looking to experience the classic BMW luxury sedan without breaking the bank. Its enduring appeal lies in its blend of classic BMW styling, comfortable ride, and relatively straightforward mechanical design.
