2009 Mercedes-Benz SL-Class Review

This thing just flat corners.

The optional new Direct-Steer System on this 2009 Mercedes-Benz SL550 Roadster, combined with the suspension's standard Active Body Control, makes the car particularly well suited for, well, anything. And right now "anything" is a hard run through the San Bernardino Mountains east of Los Angeles. Top down.

The setup gives you perfect feedback and absolutely flat cornering at any speed — so much so that we're soon testing our own mettle, pushing through the next turn at a higher speed, then higher, then higher yet. We never reach the car's limits; instead we reach ours and back off lest we test the laws of physics on a road with no Armco and a 7,500-foot elevation.

A Look at the New Look
The 2009 Mercedes-Benz SL550 represents the first major overhaul of the fifth-generation (R230) SL roadster since the car's introduction in 2003. Mercedes-Benz calls it a partial reskin, and the sheet metal differences are clearly visible.

Mercedes admits that the restyling was necessary because some of its customers complained of the 2003-'08 car being "too girly," perceiving it as a "chick" car. Indeed, there is no shortage of SLs being driven around by wealthy 60-year-old men and 30-year-old trophy wives.

So after more than 140,000 SLs since 2003, the company felt the iconic roadster needed a more masculine design to get more men behind the wheel. This Mercedes-Benz has clearly done.

New Tech Gets It Done
They've improved the SL under that new skin, too. The new Direct-Steer system continually varies the ratio of the steering from 12:1 to 15:1, depending on the angle of the front wheels and the speed and load forces on the suspension components. At the heart of the system is a new rack with ingeniously devised gearing — the gears actually vary in their distance from each other.

In and around the central position, the steering is a larger numerical ratio for good straight-line stability. Once the steering angle reaches 5 degrees, the ratio becomes smaller numerically and the steering quickens, reducing the number of turns lock-to-lock.

Brakes remain unchanged, with 13.8-inch-diameter front discs and 12.6-inch-diameter discs in the rear. And truth be told, no change or upgrade is needed. Apply the brakes hard and a giant hand seems to come out of nowhere to safely haul you down from any speed with excellent pedal feel and modulation.

Tire size also remains the same, 255/40WR18 front and 285/35WR18 out back, but the wheels wear a new design to match the car's more macho look.

As Easy as ABC
M-B engineers have also further refined the SL's standard Active Body Control (ABC) system. You'll remember that ABC completely eliminates antiroll stabilizer bars front and rear and replaces them with computer-controlled shock absorbers that constantly control body movement depending on the car's speed, steering angle and other factors.

In its newest iteration, the system compensates for the body's pitching, rolling and lifting movements, as well as continually adjusting the suspension settings to changing driving conditions. In fact, the system will automatically dial in oversteer when you're cornering hard to make the car more responsive, change to neutral at lower speeds, then change to understeer at high straight-line speeds to ensure straight-ahead stability.

The suspension ride is also adjustable. In more mundane everyday driving, dial in the suspension's Comfort setting and you could be in a luxury S-Class sedan for all your butt knows. Dial it up to Sport and experience a level of handling and maneuverability that is far beyond the driving capability of 99 percent of the drivers who will ever sit behind the wheel of this car.

Under the Hood
The SL's V8 still displaces 5.5 liters and develops 382 horsepower at 6,000 rpm and 391 pound-feet of torque at 2,800 rpm. But M-B claims an improvement in fuel consumption. New EPA estimates for the car are 14 city/21 highway.

We wish the carmaker would improve the DOHC engine's bottom-end torque. When you punch down the throttle, you still have to wait a few milliseconds for the revs to build and the engine to climb up on the cams. When that happens, however, things happen, fast.

M-B claims a 0-60 time of 5.3 seconds, which is quicker than about 95 percent of all other cars we've ever tested. Still, thanks to the SL's numerically low 2.65:1 rear axle ratio, you can't really call this car's acceleration explosive. Instead there's a hard, steady push against your spine and eyeballs that doesn't let up until you either lift or hit the electronically controlled rev limiter at the car's 155-mph top speed.

Automatically Cool
Backing up the engine is the same seven-speed 7G-Tronic automatic transmission from last year, which, by the way, is not the same as the seven-speed auto in the SL63 AMG version of this car. In the SL550, the trans still uses a torque converter while the new Speedshift MC7 version in the SL63 AMG replaces the torque converter with a wet clutch.

We don't like the SL550's transmission; we love it. As the revs climb, you can bang off shifts right at the redline with either the steering wheel paddles or the good old console-mounted stick. Either way, shifts are bang-quick and solid as a safe.

What are even cooler are the downshifts. The 7G-Tronic boasts fast-action downshifts with a double-declutching function that is automatically triggered during manual downshifts. What that means is that the computer blips the throttle for you just like on a stick shift transmission with a clutch. It sounds so cool and it makes you feel like Helio Castroneves — driving, not dancing.

Inside the Cockpit
Mercedes-Benz executives are very proud of the state-of-the-art telematics system in the SL. The dash-mounted monitor is now brighter with better graphics and the company claims it has a more streamlined user-friendly menu structure.

A new music capability gives you a capacity of 4GB on the 40GB hard drive, enough for storing about 1,000 tracks of music. And they'll play back with Dolby Digital 5.1 sound. You can also simply plug your SD card into the slot on the head unit and play back your own music catalog.

There's other newness inside as well, starting with a new-design three-spoke sports steering wheel with the now ubiquitous shift paddles. The instrument panel sports new-design dials with 3-D scale rings. When the ignition is switched on, the tach and speedo needles flick all the way to the peg, then settle back on the 6 o'clock position until the engine is started.

M-B claims that the new-design instrument panel provides optimal instrumentation shielding, but we found the electronic LCD information readouts virtually impossible to see, top up or down. If there is a control to make them brighter, we never found it. So when manually shifting, we never really knew what gear we were in or, for that matter, what suspension setting.

SL in Retrospect
Now that we're a few days separated from our drive, the word "capable" keeps coming to mind. This is a car that is immensely capable no matter what the road challenge or driving condition.

Yes, you can probably say the same thing about almost any Mercedes-Benz automobile. Still, we wouldn't trade the two-seat sportiness or the surrounding luxury for any other car — at least for the two days we were in the SL. It really is a unique combination of very-high-performance sports car and luxury car. There's still nothing else quite like it in the marketplace.

And the top drops in 16 seconds.

Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.