Mercedes-Benz SL-Class Performance
The SL550 and SL600 are praised for their power and comfortable handling dynamics. Test drivers, however, offer mixed feedback on their brakes and generally find their hefty weight difficult to overcome. Still, most reviewers conclude that it's a fun machine that's abilities come close to thrilling sports performance, but can't quite match its speed-demon competitors.
- "How you experience driving a 2009 Mercedes-Benz SL-Class depends entirely on which model you choose. The SL550 and SL600 are the boulevard cruisers of the bunch, although the 600's biturbo V12 makes it a tremendously powerful road burner." -- Edmunds
- "[T]hose seeking more edge in their sports cars might want to look elsewhere, because nothing about this car makes you want to drive it like you stole it." -- AutoWeek
Acceleration and Power
Test drivers, on balance, admire the SL550 and SL600 for their powerful engines and versatile transmissions.
Both the SL550 feature a 5.5-liter V8 engine that produces 382-horsepower at 6,000 rpm and 391 pound-feet of torque at 2,800 to 4,800 rpm. A seven-speed automatic transmission with Touch Shift that allows drivers to manually down- and up-shift is standard. According to Mercedes-Benz, the SL550 can accelerate from 0 to 60 mph in 5.3 seconds.
The more powerful SL600 is equipped with a 5.5-liter V12 engine that makes 510-horsepower at 5,000 rpm and 612 pound-feet of torque at 1,900 to 3,500 rpm. The SL600's standard transmission is a five-speed automatic, also with Touch Shift. Mercedes-Benz clocks its 0 to 60 acceleration time at an impressive 4.4 seconds.
The EPA reports a city/highway fuel economy of 13/21 mpg with the SL550 and 11/18 mpg with the SL600.
- "The SL550's 5.5-liter V8 is the best choice for mere mortals, offering acceptable power at a good price, although there is something purely sumptuous about the 510-horsepower V12 of the SL600." -- Kelley Blue Book
- "The 5.5-liter V-8 launches the big roadster with a solid whoosh, hitting 60 mph in 5.3 seconds, Mercedes says. Speed freaks who want more must pony up even bigger bucks. ... The seven-speed automatic, which electronically adapts to driving style, provides smooth performance and refinement." -- Arizona Republic
- "As for the engines, you won't find too many complaints on these pages about the 382-hp, 5.5-liter V-8 under the hood of any Benz model. Its prodigious torque (some 391 pound-feet) shoves the roadster forward with as much authority as most of its high-powered executive owners command at their respective companies. ... Both transmissions, however, feature three driver-selectable modes: comfort, sport, and manual-with the slowest yet most seamless shifts in comfort mode, slightly faster and crisper shifts in sport, and fast but sometimes harsh shifts in manual." -- Car and Driver
- "With so much power on tap not far off idle, I can understand why the seven-speed automatic transmission - which includes a Comfort mode that starts the transmission in second gear (to lower engine rpm when accelerating on slick roads) and a Sport setting that starts it in first - has been programmed to upshift rapidly through the gears as the car gains speed; even in the higher gears the engine manages to pull strongly. However, I think Mercedes went a bit overboard. Though the quick upshifts can save fuel and make for quieter operation, they sometimes leave the engine bogged down in too high of a gear when rapid acceleration - or just a not-so-cheap thrill - is needed. To avoid this, I found myself using the automatic's clutchless-manual mode more than I do in most cars just to keep the engine's abundant power available." -- Cars.com
Handling and Braking
For the most part, test drivers appear satisfied with the SL's sporty handling dynamics -- though its braking system does receive mixed reviews. Every SL operates on a rear-wheel drivetrain and features Active Body Control (ABC), which adjusts each wheel's suspension as needed to create a balanced ride. An Electronic Stability Program (ESP) is also standard, and reads steering and braking inputs and compares them to the vehicle's course in order to correct understeer and oversteer by adjusting the SL's brakes and engine power output.
- "As you drive the 2009 Mercedes-Benz SL you'll feel exactness in the steering wheel and brakes and in the way the car corners and copes with emergency situations. What you don't feel is the army of computers monitoring, controlling and adjusting every facet of the SL driving experience." -- Kelley Blue Book
- "Steering, brakes and handling have also been greatly improved across the SL lineup. The new Direct-Steer system continually varies the steering ratio depending on the front wheel angle, speed and load forces on the suspension components. Also, the revised Active Body Control features computer-controlled shock absorbers that constantly control body movement depending on the car's speed, steering angle and other factors. The overall result is a better SL (particularly in AMG form) that provides excellent feedback and flat cornering at any speed." -- Edmunds
- "Sharply maneuverable, with excellent steering and brakes, SL still feels too heavy. This is a 4,200-pound sports car, after all, and no amount of technology or engineering can hide that. ... Mercedes should look at lightening the load for better handling and economy." -- Arizona Republic
- "As ever, ABC (active body control) does a remarkable job of keeping body roll completely snuffed while soaking up all but the most torrid impacts; between the air springs and the solid construction inherent to all recent SLs, we noticed only a few jolts during our entire stint behind the wheels of both SL550 and SL600 models-impacts that probably would have caused much more of a disturbance to lesser cars and their occupants. The SL's brakes, however, felt a touch artificial as the hypersensitive anti-lock system constantly fiddled with the brake pressure at each wheel, especially when trail-braking into corners or on rough patches." -- Car and Driver
- "Convertible cowl shake and body quiver are not noticeable with the top up, but a little bit filters through with the top down. ... SL never feels truly agile, though it corners with linear steering and little body lean. Good stopping control is marred by soft pedal action." -- Consumer Guide
- "[T]he braking action seems somehow delayed, leaving you with a 'whoa!' feeling far too often." -- AutoWeek