The Mercedes-Benz 300 SL, part of the R107 generation, represented a significant evolution of the iconic SL roadster lineage. Produced from May 1985 to August 1989, the 300 SL CAT (Catalytic Converter) variant occupied a middle ground in the R107 lineup, offering a balance between performance and refinement. This facelifted R107, introduced in 1985, featured subtle but important updates to the exterior and interior, solidifying its position as a luxurious and capable grand tourer. The 300 SL CAT was aimed at buyers seeking a sophisticated open-top experience without the outright performance of the flagship 560 SL, or the more economical appeal of the smaller displacement models.
Technical Specifications
| Brand | Mercedes-Benz |
| Model | SL |
| Generation | SL (R107, facelift 1985) |
| Type (Engine) | 300 SL CAT (180 Hp) |
| Start of production | May, 1985 |
| End of production | August, 1989 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Roadster |
| Seats | 2 |
| Doors | 2 |
| Fuel consumption (urban) | 14.9 l/100 km (15.8 US mpg / 19 UK mpg) |
| Fuel consumption (extra urban) | 8.3 l/100 km (28.3 US mpg / 34 UK mpg) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 9.9 sec |
| Acceleration 0 – 62 mph | 9.9 sec |
| Acceleration 0 – 60 mph | 9.4 sec |
| Maximum speed | 200 km/h (124.27 mph) |
| Weight-to-power ratio | 8.4 kg/Hp |
| Weight-to-torque ratio | 6 kg/Nm |
| Power | 180 Hp @ 5700 rpm |
| Power per litre | 60.8 Hp/l |
| Torque | 250 Nm @ 4400 rpm (184.39 lb.-ft. @ 4400 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M 103 E 30 / 103.982 |
| Engine displacement | 2962 cm3 (180.75 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 88.5 mm (3.48 in.) |
| Piston Stroke | 80.25 mm (3.16 in.) |
| Compression ratio | 9.2:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | SOHC |
| Engine oil capacity | 6 l (6.34 US qt | 5.28 UK qt) |
| Coolant capacity | 8 l (8.45 US qt | 7.04 UK qt) |
| Kerb Weight | 1510 kg (3328.98 lbs.) |
| Max. weight | 1930 kg (4254.92 lbs.) |
| Max load | 420 kg (925.94 lbs.) |
| Fuel tank capacity | 85 l (22.45 US gal | 18.7 UK gal) |
| Length | 4390 mm (172.83 in.) |
| Width | 1790 mm (70.47 in.) |
| Height | 1305 mm (51.38 in.) |
| Wheelbase | 2460 mm (96.85 in.) |
| Front track | 1465 mm (57.68 in.) |
| Rear track | 1466 mm (57.72 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears | 5 gears, manual transmission |
| Front suspension | Double wishbone |
| Rear suspension | Trailing arm |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | Front: 205/65 R15, Rear: 205/65 R15 |
| Wheel rims size | Front: 7J x 15, Rear: 7J x 15 |
Powertrain & Engine Architecture
The heart of the 300 SL CAT was the M103 E 30 inline-six engine, a 2.962-liter (180.75 cubic inch) powerplant. This engine featured a single overhead camshaft (SOHC) design and utilized Bosch K-Jetronic multi-port fuel injection, a sophisticated system for its time that contributed to improved fuel efficiency and reduced emissions. The catalytic converter, denoted by the “CAT” in the model name, was a crucial component in meeting increasingly stringent emissions regulations. The engine produced 180 horsepower at 5700 rpm and 250 Nm (184 lb-ft) of torque at 4400 rpm. The engine’s robust construction and relatively simple design contributed to its longevity and ease of maintenance. The 300 SL was equipped with a five-speed manual transmission as standard, providing drivers with precise control over the engine’s power.
Driving Characteristics
The 300 SL CAT offered a refined and comfortable driving experience. While not as overtly sporty as some of its rivals, the combination of the M103 engine and the five-speed manual transmission provided adequate performance for spirited driving. Acceleration from 0 to 60 mph took approximately 9.4 seconds, and the car could reach a top speed of 200 km/h (124 mph). The gear ratios were well-chosen, offering a balance between acceleration and cruising ability. Compared to the higher-output 560 SL, the 300 SL felt less stressed at higher speeds, and its lighter weight contributed to more nimble handling. The manual transmission allowed for greater driver engagement, while the suspension provided a comfortable ride without sacrificing too much handling precision.
Equipment & Trim Levels
The 300 SL CAT came standard with a respectable array of features for a luxury roadster of the era. These included leather upholstery, power windows, central locking, and an AM/FM stereo. Optional extras were plentiful, allowing buyers to customize their vehicles to their preferences. Popular options included air conditioning, a sunroof, and upgraded sound systems. The interior design was typically Mercedes-Benz – understated elegance with a focus on quality materials and craftsmanship. The dashboard layout was functional and easy to use, with clearly marked gauges and controls.
Chassis & Braking
The R107 SL chassis was a robust and well-engineered structure. The 300 SL CAT featured a double wishbone front suspension and a trailing arm rear suspension, providing a comfortable ride and predictable handling. Braking duties were handled by ventilated discs at the front and solid discs at the rear, supplemented by an anti-lock braking system (ABS) which was becoming increasingly common on luxury vehicles. The steering was a recirculating ball system, offering a good balance between feel and ease of use. The car’s weight distribution was relatively balanced, contributing to its stable handling characteristics.
Market Reception & Comparison
The 300 SL CAT was generally well-received by automotive critics. It was praised for its comfortable ride, refined interior, and reliable engine. However, some critics noted that its performance was not as exhilarating as that of the 560 SL. Compared to the 280 SL, the 300 SL offered a noticeable increase in power and torque, but at a higher price point. Fuel economy was reasonable for a vehicle of its size and type, although it was not a primary selling point. The 300 SL CAT represented a sweet spot in the R107 lineup, offering a good balance of performance, luxury, and value.
Legacy
The Mercedes-Benz 300 SL CAT has proven to be a durable and reliable classic car. The M103 engine is known for its longevity, and many examples are still on the road today. The R107 SL, in general, has gained a strong following among collectors and enthusiasts. The 300 SL CAT, with its combination of classic styling, comfortable ride, and reliable powertrain, remains a desirable and attainable entry point into the world of classic Mercedes-Benz roadsters. Parts availability is generally good, and the car’s relatively simple mechanical design makes it relatively easy to maintain. In the used car market, well-maintained examples of the 300 SL CAT command respectable prices, reflecting their enduring appeal and classic status.
