The BMW 635CSi, produced from 1987 to 1989, represents the final iteration of the E24 6 Series coupe. This facelifted model, distinguished by its subtle aerodynamic enhancements and updated interior, solidified the 6 Series’ reputation as a grand tourer blending performance, luxury, and sophisticated styling. The 635CSi occupied the top-tier performance position within the E24 range, offering a significant step up in power and refinement compared to the 630CSi and 633CSi models. It was BMW’s flagship coupe during this period, aimed at buyers seeking a sporty yet comfortable long-distance vehicle.
Technical Specifications
| Brand | BMW |
| Model | 6 Series |
| Generation | 6 Series (E24, facelift 1987) |
| Type (Engine) | 635CSi (211 Hp) cat |
| Start of production | 1987 |
| End of production | 1989 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Coupe |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 17 l/100 km (13.8 US mpg, 16.6 UK mpg, 5.9 km/l) |
| Fuel consumption (extra urban) | 8.2 l/100 km (28.7 US mpg, 34.4 UK mpg, 12.2 km/l) |
| Fuel consumption (combined) | 11.8 l/100 km (19.9 US mpg, 23.9 UK mpg, 8.5 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 8.1 sec |
| Acceleration 0 – 62 mph | 8.1 sec |
| Acceleration 0 – 60 mph | 7.7 sec |
| Maximum speed | 225 km/h (139.81 mph) |
| Weight-to-power ratio | 7 kg/Hp, 143.1 Hp/tonne |
| Weight-to-torque ratio | 4.8 kg/Nm, 206.8 Nm/tonne |
| Power | 211 Hp @ 5700 rpm |
| Power per litre | 61.5 Hp/l |
| Torque | 305 Nm @ 4000 rpm (224.96 lb.-ft. @ 4000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M30B35 |
| Engine displacement | 3430 cm3 (209.31 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 92 mm (3.62 in.) |
| Piston Stroke | 86 mm (3.39 in.) |
| Compression ratio | 9:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| 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 | 1475 kg (3251.82 lbs.) |
| Max. weight | 1895 kg (4177.76 lbs.) |
| Max load | 420 kg (925.94 lbs.) |
| Trunk (boot) space – minimum | 413 l (14.58 cu. ft.) |
| Fuel tank capacity | 70 l (18.49 US gal | 15.4 UK gal) |
| Length | 4815 mm (189.57 in.) |
| Width | 1725 mm (67.91 in.) |
| Height | 1365 mm (53.74 in.) |
| Wheelbase | 2625 mm (103.35 in.) |
| Front track | 1435 mm (56.5 in.) |
| Rear (Back) track | 1465 mm (57.68 in.) |
| Drag coefficient (Cd) | 0.41 |
| Minimum turning circle | 11.7 m (38.39 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 5 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 |
| Steering type | Cone worm with recirculation balls |
| Tires size | 195/70 R14 |
| Wheel rims size | 6.5J x 14 |
Powertrain & Engine Architecture
The heart of the 635CSi is the M30B35 engine, a 3.4-liter inline-six cylinder powerplant. This engine is a descendant of the long-running M30 family, known for its smoothness and durability. The B35 variant featured Bosch Motronic fuel injection and a revised cylinder head with four valves per cylinder, significantly increasing power output compared to earlier M30 iterations. The engine produced 211 horsepower at 5700 rpm and 305 Nm (224.96 lb-ft) of torque at 4000 rpm. The engine’s layout is front-mounted and longitudinal, driving the rear wheels. The 635CSi was exclusively offered with a 5-speed manual transmission, providing a direct and engaging driving experience. This transmission was chosen to handle the engine’s power and deliver optimal performance.
Driving Characteristics
The 635CSi offered a compelling blend of performance and comfort. The 5-speed manual transmission allowed for precise control and spirited acceleration. The car could reach 0-60 mph in approximately 7.7 seconds and achieve a top speed of 139.81 mph. The inline-six engine delivered smooth, linear power throughout the rev range, making it well-suited for both highway cruising and spirited driving on winding roads. The suspension, featuring McPherson struts in the front and independent coil springs in the rear, provided a comfortable ride while maintaining good handling characteristics. The car felt balanced and predictable, inspiring confidence in the driver.
Equipment & Trim Levels
The 635CSi was well-equipped for its time, offering a range of standard features including power windows, power locks, air conditioning, and a premium sound system. The interior was typically trimmed with leather upholstery, and wood trim was used on the dashboard and door panels to create a luxurious ambiance. Optional extras included a sunroof, heated seats, and a more advanced sound system. The 635CSi represented the highest trim level within the E24 range, offering a more refined and feature-rich experience compared to the 630CSi and 633CSi.
Chassis & Braking
The E24 6 Series featured a robust chassis with independent suspension all around. The front suspension utilized McPherson struts with coil springs and an anti-roll bar, while the rear suspension employed independent coil springs. The 635CSi was equipped with ventilated disc brakes at the front and solid disc brakes at the rear, providing ample stopping power. The steering system was a cone worm with recirculation balls, offering precise and responsive control. The car’s weight distribution was carefully balanced, contributing to its neutral handling characteristics.
Market Reception & Comparison
The 635CSi was widely praised by automotive critics for its performance, handling, and luxurious interior. It was considered a worthy competitor to other grand tourers of the era, such as the Mercedes-Benz 560SEC and the Porsche 911. Compared to the 630CSi and 633CSi, the 635CSi offered a significant performance advantage, thanks to its larger engine and more advanced technology. However, it also came with a higher price tag. Fuel economy, while respectable for the time, was not a strong point, with combined fuel consumption around 19.9 US mpg.
Legacy
The BMW 635CSi remains a highly sought-after classic car today. Its combination of performance, luxury, and timeless styling has made it a favorite among collectors and enthusiasts. The M30B35 engine is known for its durability and relatively straightforward maintenance, although parts availability can be a challenge. Well-maintained examples of the 635CSi command high prices in the used car market, reflecting their enduring appeal and historical significance. The E24 6 Series, and particularly the 635CSi, is considered a landmark achievement in BMW’s history, representing a golden age of automotive design and engineering.
