1973-1980 Mercedes-Benz SL (R107) 450 SL V8 (225 Hp) Automatic

The Mercedes-Benz R107 generation SL, produced from 1971 to 1989, represented a significant evolution for the iconic SL roadster. The 450 SL, introduced in 1973 and continuing through 1980, was a cornerstone of this generation, offering a blend of luxury, performance, and the robust reliability expected of a Mercedes-Benz. This variant, powered by the 4.5-liter V8 engine and paired with a three-speed automatic transmission, occupied a premium position within the R107 lineup, appealing to buyers seeking a comfortable and capable grand tourer. It was a direct successor to the earlier 280 SL and paved the way for the later, more fuel-injected models.

Technical Specifications

Brand Mercedes-Benz
Model SL
Generation SL (R107)
Type (Engine) 450 SL V8 (225 Hp) Automatic
Start of production 1973
End of production 1980
Powertrain Architecture Internal Combustion engine
Body type Roadster
Seats 2
Doors 2
Fuel consumption (combined) 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 8.8 sec
Acceleration 0 – 62 mph 8.8 sec
Acceleration 0 – 60 mph 8.4 sec
Maximum speed 215 km/h (133.59 mph)
Weight-to-power ratio 7 kg/Hp, 142 Hp/tonne
Weight-to-torque ratio 4.2 kg/Nm, 238.5 Nm/tonne
Power 225 Hp @ 5000 rpm
Power per litre 49.8 Hp/l
Torque 378 Nm @ 3000 rpm (278.8 lb.-ft. @ 3000 rpm)
Engine layout Front, Longitudinal
Engine Model/Code M 117.982
Engine displacement 4520 cm3 (275.83 cu. in.)
Number of cylinders 8
Engine configuration V-engine
Cylinder Bore 92 mm (3.62 in.)
Piston Stroke 85 mm (3.35 in.)
Compression ratio 8.8:1
Number of valves per cylinder 2
Fuel injection system Multi-port manifold injection
Engine aspiration Naturally aspirated engine
Valvetrain SOHC
Engine oil capacity 8 l (8.45 US qt | 7.04 UK qt)
Coolant capacity 15 l (15.85 US qt | 13.2 UK qt)
Kerb Weight 1585 kg (3494.33 lbs.)
Max. weight 2015 kg (4442.31 lbs.)
Max load 430 kg (947.99 lbs.)
Trunk (boot) space – maximum 252 l (8.9 cu. ft.)
Fuel tank capacity 90 l (23.78 US gal | 19.8 UK gal)
Permitted trailer load with brakes (12%) 1200 kg (2645.55 lbs.)
Permitted trailer load without brakes 750 kg (1653.47 lbs.)
Length 4370 mm (172.05 in.)
Width 1790 mm (70.47 in.)
Height 1300 mm (51.18 in.)
Wheelbase 2455 mm (96.65 in.)
Front track 1452 mm (57.17 in.)
Rear (Back) track 1440 mm (56.69 in.)
Minimum turning circle 10.34 m (33.92 ft.)
Drivetrain Architecture Rear wheel drive
Number of gears and type of gearbox 3 gears, automatic transmission
Front suspension Coil spring, Double wishbone
Rear suspension Threaded twist beam, Transverse stabilizer, Coil spring
Front brakes Ventilated discs, 278 mm
Rear brakes Disc, 279 mm
Steering type Cone worm with recirculation balls
Power steering Hydraulic Steering
Tires size Front: 205/70 VR14, Rear: 205/70 VR14
Wheel rims size Front: 6.5J x 14, Rear: 6.5J x 14

Powertrain & Engine Architecture

The heart of the 450 SL is the M117.982 4.5-liter V8 engine. This engine, a naturally aspirated, overhead camshaft (SOHC) design, featured a cast iron block and aluminum cylinder heads. It utilized Bosch K-Jetronic mechanical fuel injection, a system known for its reliability and consistent fuel delivery, though less sophisticated than later electronic systems. The engine produced 225 horsepower at 5000 rpm and 278.8 lb-ft of torque at 3000 rpm. The three-speed automatic transmission, a robust unit for its time, was designed to provide smooth and comfortable shifts, prioritizing a relaxed driving experience over outright performance. This transmission was not known for its efficiency by modern standards, contributing to the car’s relatively high fuel consumption.

Driving Characteristics

The 450 SL Automatic offered a distinctly different driving experience compared to its manual transmission counterparts or the later, more powerful 450 SL models. The automatic transmission, while providing ease of use, resulted in slightly slower acceleration – 0-60 mph in around 8.4-8.8 seconds. The gear ratios were optimized for cruising, making it a comfortable highway companion. However, it lacked the responsiveness and driver engagement of the manual versions. The torque converter smoothed out power delivery, making the engine feel less eager to rev. The car’s weight, around 3,500 pounds, was noticeable, particularly during spirited driving. The focus was clearly on comfortable, refined touring rather than sporty handling.

Equipment & Trim Levels

The 450 SL came reasonably well-equipped as standard. Interior appointments included leatherette upholstery (genuine leather was an option), wood trim on the dashboard and center console, and power windows. Air conditioning was a common option, almost essential for comfortable operation in warmer climates. Other available options included a sunroof, power steering (standard in many markets), and a premium sound system. The dashboard layout was functional and elegant, typical of Mercedes-Benz design of the era. Trim levels were relatively simple; options were generally added individually rather than packaged into distinct tiers.

Chassis & Braking

The R107 SL utilized a robust chassis with independent suspension all around. The front suspension featured coil springs and double wishbones, while the rear employed a threaded twist beam axle with coil springs and a transverse stabilizer bar. This setup provided a comfortable ride, though handling was not as sharp as some contemporary sports cars. Braking was initially equipped with ventilated discs at the front and solid discs at the rear. Power-assisted steering was standard in many markets, making the car relatively easy to maneuver. The tires were typically 205/70 VR14, providing adequate grip for the car’s performance capabilities.

Market Reception & Comparison

The 450 SL Automatic was generally well-received by critics and buyers alike. It was praised for its comfortable ride, luxurious interior, and reliable engine. However, some reviewers noted the relatively high fuel consumption and the lack of sporty handling compared to other roadsters. Compared to the earlier 280 SL, the 450 SL offered significantly more power and performance. Later models, such as the 450 SL with fuel injection, offered improved fuel economy and slightly increased power. The automatic transmission was a popular choice, particularly among buyers who prioritized ease of use over outright performance.

Legacy

The 450 SL remains a popular classic car today, prized for its elegant styling and robust engineering. The M117 V8 engine is known for its durability and relatively simple maintenance requirements, although parts availability can sometimes be a challenge. The automatic transmission, while not as desirable as the manual version among enthusiasts, is generally reliable if properly maintained. Well-maintained examples command respectable prices in the used car market, reflecting the car’s enduring appeal and status as a symbol of 1970s luxury. The R107 generation SL, and the 450 SL in particular, helped solidify Mercedes-Benz’s reputation for building high-quality, long-lasting automobiles.

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