2008 Mercedes-Benz GL Class

2008 Mercedes-Benz GL Class

Today, the new Mercedes-Benz GL550 and ML550 models are making their driving debut at an event here for the news media. The high-technology 5.5-liter V8 engine that powers many Mercedes-Benz passenger cars is now available in two of the company’s popular sport utility vehicles, and journalists will have an opportunity to drive both new models through the scenic roads of Idaho and hear from the company’s engineering and marketing experts.Currently available at dealerships, the fully equipped GL550 is joining the award-winning seven-passenger GL450, the first full-size SÚV from Mercedes-Benz, and the recently introduced diesel-powered GL320 CDI model. The well-known five-passenger ML500 is being replaced by the ML550 model, which boasts a horsepower increase of more than 26 percent over the previous 5.0-liter V8.

A totally new class of Mercedes-Benz for 2007, the GL won Motor Trend magazine’s well-known 2007 Sport Útility of the Year award as well as a 5Best Award in the Luxury Sport Útility category from Car and Driver magazine. The first seven-passenger full-size SÚV wîth a unibody chassis, the GL is characterized by sweeping front fenders, dramatic shoulder lines and a sharply angled windshield. The GL-Class also features four-wheel independent suspension and height-adjustable Airmatic suspension for unprecedented comfort and handling.

With nearly all previous options now made standard equipment, the new GL550 comes wîth 21-inch AMG wheels fitted wîth 295 / 45 R 21 all-season tires, flared fenders, a three-bar front grille, running boards, four-exit rectangular exhaust pipes and chrome roof rails, side molding and load sill. Inside, the GL is fitted wîth real wood trim, 8-way power front seats and a stationary rear sunroof over the third-row seats. The two third-row seats can be stowed electrically at the push of a button, either separately or together, to provide a totally flat cargo floor for 43.8 cubic feet of cargo, and wîth the second row seats stowed as well, there’s more than 83 cubic feet of cargo room.

The ML550 gets AMG styling, which includes deeper front and rear under-bumper aprons, 19-inch wheels wîth all-season tires and running boards, all as standard equipment. Beneath its sleek exterior is a unit body platform and four-wheel independent suspension that deliver impressive on-road driving performance and comfort. Úseful technology abounds in the M-Class, including a standard seven-speed automatic transmission, full-time four-wheel-drive, four-wheel traction control and optional features such as height-adjustable AIRMATIC air suspension.

Price: $53,400 – 77,375.
Invoice: $49,660 – 71,960.

The M-Class cabin features a sport-oriented instrument panel, a multi-function §teering wheel and rich interior materials. Úp to 72.4 cubic feet of flexible cargo room provides ample space for anything from luggage and shopping bags to antiques and sports equipment. An easy-to-operate, fold-down rear seat is split 60/40 so that one or two people can ride in the back, even when the vehicle is loaded wîth long objects such as bicycles or lumber. Two convenient options makes loading and unloading easier – a power liftgate and a storage system that features an adjustable bar to secure cargo of varying size and shape. Incidentally, the ML350 gets a five-star rating from the National Highway Traffic Safety Administration and has been designated a ‘Top Pick’ by the Insurance Institute for Highway Safety.

The new GL550 and ML550 are powered by a 5.5-liter all-aluminum V8 in produces 382 hp and 391 foot-pounds or torque, wîth maximum torque available from 2,800 to 4,800 rpm, providing impressive engine response over a broader RPM range. Not only does the 5.5-liter V8 come wîth four valves per cylinder, but the high-tech engine also features double overhead camshafts in each cylinder bank and variable valve timing for both the intake and exhaust valves. The new engine also has ‘tumble flaps’ in the intake for better fuel economy and an electronically controlled two-stage intake manifold that broadens the power curve.

The 5.5-liter V8 is equipped wîth tumble flaps in the intake passages near the combustion chamber. The tumble flaps pivot open under partial load, improving combustion by creating additional turbulence around the intake valve and in the combustion chamber. During higher engine loads such as full throttle, the tumble flaps are completely recessed in the wall of the intake manifold. While better combustion helps improve engine torque, the primary purpose of the tumble flaps is to further increase fuel economy, and tests show that the tumble flaps indeed boost gas mileage by nearly two percent.

Valve timing is automatically adjusted by electro-hydraulic vane-type adjusters on the end of each camshaft. At partial throttle, the adjusters keep the exhaust valves open as the intake valves are opening, using this valve overlap for internal exhaust gas recirculation, reducing exhaust emissions and improving fuel economy. Approaching full throttle, the camshaft adjustment optimizes valve timing for maximum power. While variable valve timing gets a lot of credit for the engine’s unusually broad torque curve, a two-stage magnesium intake manifold plays a key role as well. At relatively low engine speeds, a set of flaps in the manifold close off short intake passages, forcing intake air to take a much longer route into the engine. This creates pressure waves that help the intake process and improve torque at lower engine speeds. Above 3,500 rpm, the flaps open and intake air flows the shortest distance to the combustion chambers, helping to make more horsepower, especially at higher speeds.

Both the 2008 M-Class and GL-Class lines come standard wîth ESP stability control, ABS anti-lock brakes, two-stage adaptive air bags for the driver and front passenger, door-mounted side air bags in front and rear, curtain side air bags and adaptive belt tensioners and belt force limiters. A rollover sensor can activate the belt tensioner and curtain air bags if the vehicle senses an imminent rollover. The M-Class and GL-Class sport utility vehicles (along wîth the R-Class SÚV) are produced at the Mercedes-Benz plant in Tuscaloosa, Alabama, which began production in 1997 wîth the first-generation M-Class. Since 2001, more than $600 million has been invested to expand the facility for production of the three SÚV lines.

Body Styles, Trim Levels and Options

The 2008 Mercedes-Benz GL-Class is a large luxury SUV available in three models that each seat seven passengers. The GL450 and GL320 CDI are equipped identically, save for their powertrains. Standard equipment includes 18-inch wheels, “MB-Tex” cloth upholstery, a leather-wrapped steering wheel, dual-zone automatic climate control, power front seats with heat, a power split-folding third-row seat, the COMAND electronics interface and an eight-speaker audio system with glovebox-mounted six-CD changer and auxiliary audio input. The pricey Premium I Package includes front seat memory functions, a power steering column, a power liftgate, a sunroof, a navigation system with a rearview camera, parking sensors and a Harman Kardon Logic7 sound system with satellite radio.

The Premium II Package includes all of the Premium I equipment, plus three-zone climate control (also available as a stand-alone option), rear air-conditioning and adaptive bi-xenon headlamps. The Heating Package adds a heated steering wheel and rear seats, while the Full-Leather Package upgrades the already well-crafted interior. The GL550 includes all of the above equipment as standard and adds 21-inch wheels and unique exterior styling details. Stand-alone options on the GL450 and GL320 CDI include adaptive cruise control and keyless ignition, while all GL-Class models can be equipped with a rear-seat DVD entertainment system and an iPod integration kit. The Enhanced Off-Road Package is available on the GL450 only.

Interior Design

The GL’s cabin is well-appointed and a comfortable place to be. Fit and finish is as it should be, seat comfort is exceptional, and headroom and legroom are ample for most positions. The second row could benefit from being able to move fore and aft, as it can get tight with taller occupants seated up front. Nice touches include a one-touch up and down function for all four windows and flush-folding rear headrests to improve the driver’s rearward vision (an innovation missing on Benz’s R-Class). Third-row access is also well thought out. With the second- and third-row seats lowered, 83 cubic feet of cargo volume is available, which is much smaller than full-size luxury SUVs like the Cadillac Escalade but on par with vehicles like the Acura MDX.

Powertrains and Performance

Each model within the GL-Class has its own engine, but all come with a seven-speed automatic and 4Matic all-wheel drive. The GL450 is powered by a 4.7-liter V8 that makes 335 hp and 339 pound-feet of torque. When fitted with the optional Enhanced Off-Road Package, the GL450 gains center and rear locking differentials, a two-speed transfer case with low-range gearing, and underbody skid plates.

In performance testing, we found the GL450 capable of hitting 60 mph in a quick 6.7 seconds. EPA fuel economy estimates for 2008 are 13 mpg city/18 mpg highway. The GL320 CDI is powered by a 3.0-liter turbodiesel V6. Like all diesels, horsepower is low and torque is high, with 215 hp and 398 lb-ft of torque. Diesels also tend to get better fuel economy, and the GL320 gets an impressive 18/24 mpg rating. Because of their more stringent emissions standards, the GL320 CDI is not sold in several states, including California, New York and Vermont. The GL550 is powered by a 5.5-liter V8 that produces 382 hp and 391 lb-ft of torque.

Driving Impressions

Even with its 4.7-liter V8, the Mercedes-Benz GL450 was the muscle car of its class — and the new GL550 raises the bar even higher. Either gasoline-V8-powered GL is quicker to 60 mph than any other large SUV we’ve tested, including the Audi Q7 4.2 and Cadillac Escalade. The large Benz is also quiet on the highway, with minimal wind and road noise. Although the diesel GL320 CDI isn’t going to break any acceleration records, passing and merging maneuvers come easily, as the seven-speed automatic transmission does an exemplary job of keeping the engine in the meat of its power band. In addition, the GL320′s V6 is so quiet and refined you’re scarcely aware it’s actually a diesel. Some drivers might find the Mercedes GL’s handling to be a bit wallowy — this isn’t a truck you toss around for the sheer joy of it. But the ride and handling compromise is acceptable, and the GL’s steering, although a bit slow, is nicely weighted and never numb.

Safety

Standard safety features on the 2008 Mercedes-Benz GL-Class include stability control, antilock brakes, whiplash-reducing front headrests, first- and second-row side airbags and full-length side curtain airbags with an integrated rollover sensor. Hill start assist, hill-descent control and TeleAid are also included. Buyers of the GL450 and GL320 CDI wanting a rearview camera, and front and rear parking sensors should note that they are only available as part of the Premium Package. These items are standard on the GL550.