1985-1989 Mercedes-Benz SL (R107 facelift ) 500 SL CAT V8 (223 Hp) Automatic

The Mercedes-Benz SL (R107) 500 SL CAT, produced from September 1985 to August 1989, represented the pinnacle of performance within the R107 generation. This facelifted model, part of the long-running R107 series built on the 123 platform, offered a luxurious and powerful grand touring experience. The “CAT” designation refers to the catalytic converter, mandated for emissions control in many markets during this period. Positioned as the top-of-the-line SL, the 500 SL catered to buyers seeking the most potent engine option and a refined driving experience, distinguishing itself from the more economical 300 SL and 420 SL models.

The heart of the 500 SL CAT is the M 117 E 50 engine, a 4.973-liter (303.47 cubic inches) naturally aspirated V8. This engine, internally designated 117.964, featured a cast iron block and aluminum cylinder heads. It employed Bosch K-Jetronic multi-port fuel injection, a mechanical system known for its reliability and precise fuel delivery. The valvetrain utilized a single overhead camshaft (SOHC) design with two valves per cylinder. Producing 223 horsepower at 4700 rpm and 358 Nm (264.05 lb-ft) of torque at 3500 rpm, the M 117 E 50 delivered substantial power for its time. The engine was longitudinally mounted, driving the rear wheels. The 500 SL was exclusively paired with a four-speed automatic transmission, designed to provide smooth and effortless gear changes, complementing the car’s grand touring character.

Driving the 500 SL CAT offered a distinctly different experience compared to its siblings. The increased power and torque resulted in significantly quicker acceleration – 0 to 60 mph in approximately 7.4 seconds and a top speed of 133.59 mph (215 km/h). While the automatic transmission wasn’t geared for outright performance like a manual, it provided a relaxed and comfortable driving experience, ideal for long-distance cruising. The gear ratios were optimized for smooth acceleration and highway efficiency. Compared to the 300 SL, the 500 SL offered a noticeable surge in power, while the 420 SL, though closer in performance, lacked the ultimate responsiveness of the 5.0-liter V8. The heavier engine did slightly impact handling, but the well-tuned suspension minimized body roll and maintained a composed ride.

The 500 SL CAT came standard with a high level of equipment befitting its flagship status. Interiors featured leather upholstery, wood trim, and power-adjustable seats. Standard features included air conditioning, power windows, central locking, and an AM/FM radio with cassette player. Optional extras included a sunroof, upgraded sound system, and automatic climate control. The dashboard layout was typical of Mercedes-Benz in the 1980s, characterized by a functional and elegant design. The exterior styling, updated with the 1985 facelift, featured a flatter front end and integrated bumpers, giving the car a more modern appearance.

The R107 500 SL CAT utilized a robust chassis and braking system. The front suspension employed a double wishbone design, while the rear featured a threaded twist beam axle. This setup provided 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) for enhanced safety. The steering system was a cone worm with recirculation balls, providing a weighted and precise feel. Standard tire size was 205/65 R15 on 7J x 15 inch wheels.

Contemporary reviews praised the 500 SL CAT for its powerful engine, luxurious interior, and comfortable ride. Critics noted the car’s impressive acceleration and effortless cruising ability. Fuel economy, however, was a common concern, with reported figures of 16.5 l/100 km (14.3 US mpg) in urban driving and 10.2 l/100 km (23.1 US mpg) on the highway. Reliability was generally considered good, although the complexity of the K-Jetronic fuel injection system could require specialized maintenance. Compared to the 300 SL and 420 SL, the 500 SL offered the highest level of performance and refinement, justifying its higher price tag.

Today, the R107 500 SL CAT remains a sought-after classic. Its robust construction and relatively simple mechanics contribute to good long-term reliability, although regular maintenance is essential, particularly for the fuel injection system. Well-maintained examples command premium prices in the used car market, appealing to collectors and enthusiasts who appreciate its blend of performance, luxury, and timeless design. The M 117 engine, while not the most fuel-efficient, is known for its durability and smooth operation, ensuring that the 500 SL CAT continues to provide a rewarding driving experience for years to come.