Every subsystem of the new Explorer has been tuned, engineered and redesigned to make the 2006 model the quietest Explorer ever.
The resulting tranquility builds on Explorer's 15-year legacy of uniquely combining capability and utility with refinement. Demand for quiet, comfortable interiors only will increase as drivers spend more time commuting on increasingly congested streets.
Measured in the first row at highway speeds, Explorer is the quietest SUV in its class. Specific comparisons include:
- 10 percent quieter than the 2005 Explorer
- 20 percent quieter than the 2005 Toyota 4Runner
- Six percent quieter than a 2005 Jeep Grand Cherokee
- Six percent quieter than a 2005 Chevrolet TrailBlazer
More significantly, the Explorer is dramatically quieter when measured in the second- and third-row seats. "Measuring the sound levels in all three rows, you can see that most companies spend their money on the first row," says Lucy Yuen, Explorer NVH supervisor. "In real life, the driver and front passenger are comfortable. However, the driver will find that it's hard to hold a conversation with someone in the second row, and almost impossible to hold a conversation with someone in the third row."
Measured in the first row at highway speeds, the 2006 Ford Explorer features the quietest interior in its class.
Compared to its closest competitor, the 2005 Nissan Pathfinder, the 2006 Explorer shows a clear advantage in second-row measurements. The advantage is even more significant in the third row, where the 2006 Explorer is almost five sones quieter than the Pathfinder. The 2006 Explorer's third-row seat is as quiet at the front row in the TrailBlazer and Grand Cherokee, and significantly quieter than the front row of the 4Runner.
All these items help the 2006 Explorer receive a high score on the Articulation Index (AI) rating scale. This measure is used not only in the automotive industry but also by airplane manufacturers and architects among others. AI recognizes that higher frequencies are more important for speech intelligibility. Based on frequencies measured throughout the cabin, the 2006 Explorer is very "friendly" to these frequencies and thus conducive to conversations among those in the front, middle or third row of seats — or all three.
This goal was achieved by a fanatical attention to detail, modifying components in virtually every area. Just how fanatical? Engineers redesigned the entertainment system with a new mounting bracket to better isolate vibrations from the spinning DVD.
More significantly, the 2006 Ford Explorer's interior is dramatically quieter than its closest competitor when measured in the second- and third-row seats.
Not quite satisfied, engineers also developed a new hinge that helps prevent the viewing screen from shaking. The new hinge doesn't have a noticeable improvement in quietness, but does greatly improve the viewing experience for rear-seat passengers.
The new 2006 Explorer's chassis features a new, significantly stiffer frame and many other improvements that contribute to controlling noise before it reaches the cabin.
Polite Yet Powerful Powertrains
Both available powertrains underwent an NVH tune-up for 2006.
For example, both engines now feature an additional exhaust resonator, improving the sound quality of the exhaust under heavy acceleration. The engine mounts are now 10 percent softer, better isolating engine vibrations from intruding on the cabin.
The standard 4.0-liter V-6 received a number of improvements, including a new camshaft and spark plugs. In addition, the idle speed has been lowered from 675 to 625 revolutions per minute. These changes have combined to improve idle quality by 50 percent.
The new 4.6-liter V-8 benefits from three valves per cylinder and variable cam timing, improving performance, economy and refinement. Refinement is further improved by a larger airbox than before, delivering more air to the engine while decreasing induction noise. A new foam valley stuffer under the intake manifold's charge motion control valves helps muffle induction noise.
Both the new 4.6-liter V-8 (shown) and the improved 4.0-liter V-6 have been designed for decreased powertrain noise.
New side mirrors and roof panel help quell wind noise
The exterior development of the 2006 benefited from an increasing collaboration between the design and engineering team. Together, they were able to create a new design that looked bolder and more aggressive, yet actually generated less wind resistance and turbulence.
For example, changes were made to the roof beads, the contours in the roof stamping that run the length of the panel. Previously, these contours were stamped down into the roof. For 2006 these beads rise up above the roof panel, and the beads are sectioned, rather than running the full length of the roof.
"We found that taller is better," says Yuen. "Pushing the beads up provided a much more rigid panel that produces less noise. In addition, sectioning the beads into shorter lengths helped breakup the harmonic frequency of the panel — again resulting in less noise in the cabin."
The mirrors are larger than before for improved visibility, but actually reduce wind noise — compared both to the old design, and to tests conducted with no mirror at all.
The 2006 Ford Explorer Limited comes standard with heated side mirrors. The side mirrors on all models are larger than before, but decrease wind noise compared with tests conducted without side mirrors.
"They may be bigger," says Yuen, "but they're better in terms of how little noise they generate. The secret is in using the shape of the mirrors to manage the flow of air as much as possible.
The team used extensive computer modeling and wind-tunnel testing to perfect the shape of the new mirrors. The "sail" that attaches the mirror to the door is the right distance and just the right angle in relation to the vertical edge of the mirror housing nearest the door. That vertical edge is parallel to the window glass, creating a smooth, continuous valley that doesn't disrupt air flow between the glass and mirror housing.
The forward surface of the mirror housing was also carefully shaped to minimize turbulence that would otherwise impact the window glass. Finally, the shape of the outermost portion of the housing was tuned to help direct air away from the vehicle.
"We expected to improve on the wind noise of the 2005 model," says Yuen. "However, in testing we discovered that the new mirrors actually have a positive effect on air management. They actively prevent wind noise, verified in testing with no side mirrors at all."
Finally, the oversized moonroof features a new, improved wind deflector that helps prevent wind noise at highway speeds.
For the interior, engineers employed a host of new materials to help insulate the cabin from unwanted noise:
In addition, the heating and cooling system has been redesigned. The fan motors are improved for quieter operation, and the ducting has been optimized for reduced turbulence. These changes not only help improve efficiency but also deliver an impressive 30 percent decrease in noise.
- Act Fiber is used in the new carpet that is superior in absorbing noise yet is lighter than before. The fiber backing of the carpet is much lighter than traditional carpeting pads, saving almost 13 pounds in total weight. Yet, the fiber also does a better job a muffling road and drivetrain noise, preventing it from entering through the floorpan
- Additional insulation in the door panels and between the dash and firewall help prevent tire and powertrain noise from intruding in the cabin
- A layer of Sonotec, a lightweight fiber batting in the headliner, acts like a large acoustic tile, preventing soundwaves from echoing off the roof and back into the cabin
And, of course, those rear-seat passengers will always appreciate the quietest interior — in all three rows — of any SUV in the class.
All Ford Motor Company vehicles are subject to a battery of tests to validate the vehicle's durability, emissions, crash safety and even corrosion resistance. In addition, all body-on-frame vehicles, like the Explorer, the Ranger and the F-Series Super Duty, are subject to additional extreme-use testing to validate towing capacity payload capacity and off-road durability.
However, the Explorer program was also subject to its own, even more brutal testing at the hands of Scott Douglas, of Douglas Motor Sports. Douglas, with support from Ford Truck Motorsports, campaigns a 2002 V-6 Explorer in the Pure Stock Mini SUV class of the Best in the Desert off-road racing series.
According to Ford Truck Motorsports team leader Cliff Irey, off-road racing programs like the Douglas' Explorer campaign has a number of benefits Ford Motor Company:
"Ford Truck Motorsports is an engineering-based activity, learning about the nuts and bolts of our vehicles. Racing programs like the Best in the Desert off-road series helps improve our present and future products. Racers use vehicles way past the extremes of normal operation. Teams competing in the Best in the Desert racing series can do 100,000 miles of wear and tear in a single 250-mile race."
According to Irey, occasionally finding parts with "impaired function" are a given in this brutal environment. These parts are forwarded to the design teams for evaluation. "In some cases the engineers say, 'Yes, but you just shouldn't run into rocks the size of a Lincoln.' Other cases validate that the part performed just as it was designed. And often, engineers gain insight and inspiration of what could be improved for the next-generation components."
Irey also says that racing the Explorer in the Pure Stock Mini SUV class clearly demonstrates the off-road capabilities of the Explorer: "The Explorer is a true Sport Utility Vehicle.
For the stock class, regulations allow racers to change the shocks and springs, add a roll cage and fuel cell for racing, strip out the interior and windows to save weight, and go racing."
Rules dictate that the frame and body panels remain stock. Even the 16-inch wheels are stock, albeit wrapped in massive 35-inch BFGoodrich off-road tires. Pure Stock regulations also limit wheel travel to nine inches, and require Douglas to run stock front and rear suspension components with the exception of shocks and springs. Douglas uses prototype Rancho shocks, designed and tuned by crew chief Ted Kendall.
Scott Douglas' Best In the Desert off-road racing Explorer chassis is largely stock, except for shocks, springs, and 35-inch BFGoodrich off-road tires.
"I have to admit, we were skeptical about racing the independent rear suspension (IRS)," says Douglas. "But the handling is so superior, it's proven to be a real competitive advantage. The IRS is much more composed than live-axle trucks on the fast, high-speed sections of these races. Particularly on the washboard sections, the IRS soaks up the impacts without upsetting the truck."
In fact, the competitive advantage of the Explorer's IRS helped Douglas win his tenth off-road championship. Douglas won four out of five races during the 2004 season. His team finished second in the fifth race, as Douglas drove the first 100 miles, where he then jumped on a helicopter for transport to another race. His teammate then finished the race for points.
Douglas started the 2005 season in the Explorer decisively winning the first two races of the season. In one race, he finished an hour before the second-place finisher. Douglas' dominance of the class has led another team to develop their own IRS-equipped Explorer in hopes of derailing Douglas's attempt to win his eleventh off-road championship.
"We have raced three seasons on this truck — more than 4000 off-road race miles — and the Explorer has finished every mile of every race," say Douglas. "It's proven to be bullet proof in terms of reliability, and unstoppable on the race course."
For 2006, Explorer offers its first-ever navigation system — part of a complete interior makeover that respond to consumer demand for more upscale cabins in mainstream products. Ford's newest vehicles, such as the F-150 and Mustang, are meeting this trend — part of what the company calls Middle Market Squeeze — with acclaimed interiors after a tripling in interior-design investment.
Integrated with the audio system, the available DVD-based navigation system operates via pushbutton controls as well as through a touch-screen interface. The system is one of the first in the industry to provide voice prompts that include spoken upcoming street names.
Unlike early, CD-based units that require a half of a dozen or more discs to hold all the mapping data, Explorer's new system uses a single DVD. This one disc holds maps covering the vast majority of North America as well as Hawaii and Puerto Rico. In addition, there are maps for 20 major U.S. cities that provide street-level detail as well as the footprints of buildings.
The new system, exclusive to Ford Motor Company and available on Eddie Bauer and Limited models, is the first that provides turn-by-turn voice instructions, including street names. Where other systems' text-to-speech function is limited to, "Turn Right in one mile," the Explorer's navigation system adds street information, such as "Turn Right in one mile on Bear Mountain Road." The driver has a choice of receiving voice directions, prompts and menus in North American English, North American Spanish and Canadian French.
The 6.5-inch-wide Liquid Crystal Display (LCD) screen is up to twice as bright as competitive models, making it easier to read even in direct sunlight. It also warms up more rapidly in cold conditions, which can leave other LCD-based displays with unwanted ghost images and slow response.
The audio unit built into the system features an AM/FM tuner with Radio Broadcast Digital System (RBDS), a feature that presents station call letters, artist names and song titles on the digital radio display. In addition, it features an in-dash, six-disc CD changer that is MP3 and CD text compatible.