2007 Mercedes SL550
Introduction
The SL550 debuted at the Geneva Auto Show in Switzerland in March, 2006. It’s a vastly improved engine in a midlife facelift of the 2003 - 2006 SL Klasse.
In Europe it appears to retain the name SL500 while in the US it’s called the SL550. There’s also a V6 SL350 in Europe. It’s unknown if the smaller 450 V8 will appear in the US as the SL450.
See my SL500 pages for information on the previous models.
Major Change: Best New Engine Since 1990
Mercedes finally returns to a four-valve engine for the SL550. Mercedes introduced 32-valve quad cam V8s in the 1990 SL500, but downgraded them to three valves from 1999 - 2006.
First seen in the 2007 S-Class sedan, the new 5.5-liter engine has 382 horsepower and 391 ft-lbs. of torque, a huge increase from the old three valve V-8 engines. Not only does it have more valves, the compression ratio climbs from 10.0 : 1 to 10.7 : 1, further increasing power and fuel economy. Torque peak is one huge mesa from 2,800 to 4,800 RPM, in other words, peak torque is maintained throughout this entire band!
This is a serious increase in power. For comparison, the 1994 - 2002 12 - cylinder SL600 and S600 models put out 389 hp, or just 7 hp (less than 2%) more than the new V-8. The V-12s put out 420 ft-lbs of torque, 29 ft-lbs (7%) more than the new V-8’s, but usually added 300 lbs to the weight.
This is going to kick butt over the relatively anemic three valve engines used since 1999. See engine history below.
0 - 60 is claimed at 5.2s, a full second faster than the SL500s since 1990. Weight is 4202 pounds, about 150 pounds heavier than the past 16 years.
All this new power, and EPA MPG goes to 16/24 MPG, which is about 1 MPG better than all the SLs have been since 1996. Even earlier 1990 - 1995 SL500s sucked more gas because they lacked an overdrive on their early 4 speed transmissions.
Seven Speed Automatic
The SL550 is one of several Mercedes with the industry’s first seven-speed automatics. It improves acceleration and fuel economy. Gears are so close in the higher gears that gear changes can be barely noticeable. The seven-speed shortens 0-to-60 mph time and allows significantly quicker acceleration for highway passing. Using seven gears allows individual gears to be spaced closer together while providing a larger overall spread between the lowest and highest gear. The seven-speed can skip a gear if necessary, switching from seventh gear straight down to fifth, for example, and even from sixth to second, skipping three gears at once. We’ll have to see if it can do what it needs to, which is to drop instantly from top gear to first or second if you hammer it while coasting at reasonable speeds.
The SL55 AMG and V12 SL600 use a modified five-speed automatic.
AMG Gets Hotter, too
The blown V8 of the SL55 AMG now has 510 horsepower at 6,100 RPM, up from 493, and 531 ft-lb. of torque from 2,600 - 4,000 RPM, up from 516, only a three percent increase. Even the first blown V8 AMG SL55 is a world unto itself, so no reason to go buy a new one. The 2007 gets more power from a bigger throttle valve , a more efficient blower and a new computer. The 2007-model SL55 AMG also comes with new carbon-fiber interior trim and redesigned 19-inch five-spoke AMG wheels.
Claimed 0 - 60 times improve to 4.3s from 4.5s. You can pay extra to have the 250 kph (155 MPH) speed limiter reprogrammed to 300 kph (187 mph). I wouldn’t bother: I’ve driven these on a race track and never got above 130 MPH. The only person going faster than 155 MPH is the kid who borrows your SL55 and takes it to Vegas on the I-15.
The twin-turbo V12 of the SL600 gets a small horsepower bump to 510 hp from 493 hp, and has 612 ft-lb. of torque, up from 590 ft-lb.
Minor Changes
The new SL has a more aggressively styled front air dam and a new front grille as well as clear-lens tail lights and chrome-trimmed fog lights. The only way to notice is to count the slats on the grille: three on the 2007 and four on the 2003 - 2006.
Inside they have new metal door sills, new upholstery colors and softer leather.
The hands-free communication system is now be standard in the USA. Of course using this system while driving is a distraction. It’s an offense to drive while distracted and can cause accidents and death exactly like being drunk. Multi-handset or Bluetooth interfaces are sold separately.
Sirius satellite radio hardware comes standard. The first six months are free.
I don’t know about an iPod port.
50th Anniversary Edition
To honor the very first 300SL Roadster, a 50th Anniversary Edition of the SL roadster will be available later in 2006. A limited production run of 550 vehicles will be offered in pewter metallic with Cognac brown leather, black ash interior wood trim, and an exclusive 18” twin-five-spoke wheel.
Features
The SL550 has 12.3-inch front and 11.8-inch rear discs, while the SL600 and SL55 AMG both have 14.2-inch rotors with eight-piston front calipers and 13.0-inch rotors with four-piston rear calipers. The SL65 AMG has discs that are yet another 1.2 inches in diameter.
As on all other Mercedes, Brake Assist can potentially reduce braking distances in emergency or “panic” stops. In addition, the standard Electronic Stability Program (ESP) helps to keep the car on its intended path, preventing oversteer or understeer in turns, and providing straight-line traction control.
Metal Retracting Hard Top
The SL’s retractable hardtop opens or closes in 16 seconds. It folds into the trunk. It lays just below the trunk lid on top of your trunk space. It’s in the way for trunk loading. There’s a button to raise the roof out of the trunk a bit to ease this. With the top collapsed only 7.2 cubic feet of oddly shaped space remain, less than the eminently usable rectangular 7.9 cubic feet of the 1990 - 2002 SL500.
With the top up and out of your trunk the 2003 - 2007 SL trunk holds 10.2 cubic feet. This is a huge improvement, but defeats the whole purpose of the SL to drive with the top up.
A hydraulic pump and 11 computer-controlled hydraulic cylinders power the system. It’s all controlled by a switch on the center console.
Unlike SLs before 2003, the metal roof can never be fully removed and there is no soft top. This is great, since those of us with previous SLs leave our metal hard tops in storage or hanging from the ceiling of our garages.
ABC Active Suspension
Active suspension is designed to solve the usual tradeoff between ride comfort and handling precision. The SLs have excellent comfort and fantastic agility.
The SL chassis uses a fully independent, double-control-arm front suspension and the patented Mercedes-Benz five-link rear suspension.
All 2007 SL models come with second-generation Active Body Control (ABC), the Mercedes-Benz active-suspension technology that virtually eliminates body roll in cornering, squat under acceleration and dive during braking.
On AMG models, the ABC system is calibrated for even higher performance. Special AMG suspension struts with firmer damping and fully reworked systems such as ABS anti-lock brakes, Brake Assist, ASR traction control and ESP stability control complement the enhanced AMG chassis. Each SL model uses software programming specific to the model, akin to tuning the spring rates, shock damping and anti-roll bar stiffness of a conventional suspension.
Mercedes-Benz engineers use ABC’s interplay of hydraulic, electronic and mechanical parts to reduce body roll by 68 percent (compared to the same vehicle with a conventional suspension), providing the driver with needed feedback through the vehicle chassis.
A ‘Sport’ switch on the center console increases roll reduction to 95 percent, along with tighter shock damping.
Price and Availability
Expect it in April 2006 starting at $94,612.
Engine History
For 2007 Mercedes is returning to a high performance 4-valve V8, the same technology introduced in 1990 but downgraded in 1999 - 2006.
Mercedes introduced the high-performance variable-valve-timing quad-cam 4-valve V8 in the 1990 SL500 which continued through 1998. It had 322 - 315 hp and 347 ft-lb of torque.
Chrysler era cost reductions downgraded these engines to a lower performance 3-valve V8 in the 1999 - 2006 SL500s, including the V8 offerings in every other 2006 model. These 3-valve engines offer the same EPA fuel economy with less power (only 302 hp) and less torque (only 339 ft-lbs.) compared to the 1990 - 1998 4-valve engines. Of course marketers promoted this downgrade as some sort of benefit. Even the six-cylinder models stepped back to simpler technology and lower performance.
Thank God Mercedes returns to the better engine for the 2007 SL550.
I have to giggle that Mercedes calls these V8s “new-generation.” Mercedes is simply returning to the superior 4-valve technology they introduced in 1990 and abandoned in 1999.
The V12 turbo remains at 3 valves and no one is complaining.
