The BMW 7 Series (E23) 728i, produced between 1979 and 1983, represented BMW’s initial foray into the full-size luxury sedan segment. Positioned as the entry-level model within the E23 range, it offered a more accessible price point compared to the flagship 733i and later 745i variants. The 728i was crucial in establishing the 7 Series as a technologically advanced and driver-focused alternative to traditional luxury cars from Mercedes-Benz and Jaguar. It was built on the E23 platform, which would define BMW’s top-tier sedan for a decade.
Technical Specifications
| Brand | BMW |
| Model | 7 Series |
| Generation | 7 Series (E23) |
| Type (Engine) | 728i (184 Hp) |
| Start of production | 1979 |
| End of production | 1983 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 15.1 l/100 km (15.6 US mpg, 18.7 UK mpg, 6.6 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 9.5 sec |
| Acceleration 0 – 62 mph | 9.5 sec |
| Acceleration 0 – 60 mph | 9 sec |
| Maximum speed | 195 km/h (121.17 mph) |
| Weight-to-power ratio | 8.1 kg/Hp, 123.5 Hp/tonne |
| Weight-to-torque ratio | 6.3 kg/Nm, 157.7 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 | 1490 kg (3284.89 lbs.) |
| Max. weight | 1960 kg (4321.06 lbs.) |
| Max load | 470 kg (1036.17 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 | 4 gears, manual 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 R14 |
| Wheel rims size | 6.0J x 14 |
Powertrain & Engine Architecture
The heart of the 728i was the M286 engine, a 2.8-liter inline-six cylinder powerplant. Designated the 286EZ1, this engine featured a single overhead camshaft (SOHC) valvetrain operating two valves per cylinder. It utilized Bosch K-Jetronic multi-port fuel injection, a sophisticated system for its time, providing precise fuel delivery for improved efficiency and performance. 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, emphasizing a balanced chassis and engaging driving experience. The standard transmission was a four-speed manual, though a three-speed automatic transmission was also available, impacting performance and fuel economy.
Driving Characteristics
The 728i, particularly with the manual transmission, offered a surprisingly engaging driving experience for a full-size luxury sedan. While not as overtly powerful as the 733i, the 2.8-liter engine provided adequate power for comfortable cruising and spirited driving. The manual gearbox allowed for precise control, while the automatic, though smoother, resulted in slightly slower acceleration. The 0-60 mph time was around 9 seconds, and the top speed reached 195 km/h (121 mph). The car’s relatively light weight (compared to later iterations of the 7 Series) contributed to its nimble handling. The suspension, featuring McPherson struts in the front and independent coil springs in the rear, provided a comfortable ride without sacrificing handling precision.
Equipment & Trim Levels
The 728i, as the entry-level 7 Series, came reasonably well-equipped, though options were plentiful. Standard features included power windows, central locking, and a basic stereo system. Interior upholstery was typically cloth, though leather was available as an option. Dashboard design was functional and driver-focused, with clearly laid-out gauges and controls. Optional extras included air conditioning, a sunroof, upgraded sound systems, and various trim enhancements. The 728i aimed to provide a luxurious experience without the extensive cost of the higher-end models.
Chassis & Braking
The E23 chassis was a robust and well-engineered platform. The 728i utilized ventilated disc brakes on the front wheels and solid discs on the rear, providing adequate stopping power for its weight and performance. The suspension system was tuned for a balance between comfort and handling. A stabilizer bar was fitted to the front suspension to reduce body roll during cornering. The car’s relatively low ride height contributed to its stable handling characteristics. The steering was unassisted, providing a direct and communicative feel to the driver.
Market Reception & Comparison
The 728i was generally well-received by automotive critics. It was praised for its comfortable ride, engaging handling, and relatively affordable price point within the luxury sedan segment. However, some critics noted that the engine, while smooth and refined, lacked the outright power of its larger displacement siblings. Compared to the 733i, the 728i offered a more economical option, appealing to buyers who prioritized fuel efficiency and value. Against competitors like the Mercedes-Benz S-Class and Jaguar XJ, the 728i distinguished itself with its driver-focused character and modern technology.
Legacy
The BMW E23 728i holds a significant place in BMW’s history as the first generation of the 7 Series. While the M286 engine is generally considered reliable, age and maintenance are key factors in the long-term durability of these vehicles. Common issues include wear and tear on the K-Jetronic fuel injection system and potential corrosion in the bodywork. Today, well-maintained examples of the 728i are sought after by classic BMW enthusiasts, representing a unique blend of luxury, performance, and technological innovation from the late 1970s and early 1980s. The 728i’s success paved the way for subsequent generations of the 7 Series, solidifying BMW’s position as a leading manufacturer of luxury automobiles.
