Acura MDX SUV Forums banner

1 - 20 of 27 Posts

6,809 Posts
Discussion Starter #1
5Best Trucks
We are finally dragged--kicking and screaming--into the reality that trucks are here to stay, and in very big numbers. So we pick the best.

Now that truck sales have peaked at just over 48 percent of the new-vehicle market and are poised to crater with the upward summer spike in fuel prices, we at Car and Driver have finally decided to recognize excellence in trucks. In the investment business, we would be viewed as a countercyclical indicator in such matters.

Why not just include trucks in our 10Best awards program?

The truth is that although we have been including minivans and SUVs in our 10Best deliberations since the very beginning, and looking at pickups for the past five years, these workaday machines have had difficulty passing muster with our enthusiastic band of editor/jurors. Of the 190 10Best trophies we've handed out since we inaugurated the competition in 1983, only seven have been presented to trucks--six to minivans and one to a sport-utility vehicle.

The problem is that the design elements that make a truck a truck--beefy construction, a tall stance, and an emphasis on carrying capacity--all compromise the quick reflexes, grippy traction, and high performance that we prize when we slide behind the wheel of any vehicle.
Judging by the number of letters to the editor we receive that remind us in the strongest terms that the name of the magazine is CAR and Driver, not TRUCK and Driver, we believe that our view of trucks as less satisfying to drive than cars mirrors our readers' perceptions.

And the Winners Are:

Luxury SUV: Acura MDX
Small SUV: Ford Escape
Large SUV: Toyota Highlander
Pickup: Chevrolet Silverado
Van: Honda Odyssey

At the same time, 65 percent of these same readers own trucks of one sort or another. That's why we report on and test trucks regularly. It's also why we finally decided to recognize what we think are the best trucks on the market.

The keen-eyed among you may have already noticed that we have only selected 5Best trucks as opposed to 10Best cars. This arithmetic reflects not only our preference for cars but also the fact that there are simply fewer varieties of trucks on the market. In fact, in our 2001 Car and Driver Buyers Guide, there were 198 car models listed and only 97 different SUVs, vans, and pickups. That's right in line with this two-to-one ratio in awards between cars and trucks.

What makes these trucks the best in class?

Another change from our 10Best awards is the segregation of the trucks into categories: pickups, vans, and three SUV categories--small, large, and luxury. Here again, this allocation of awards was guided roughly by the number of models on the market--19 each of vans and pickups, and a total of 58 SUVs.

For the SUVs, we decided that the 14 machines with a minimum base price (including freight) of more than $34,000 were luxury models. Then we separated the 16 sport-utes with a length no greater than 178 inches into the "small" category. The 28 remaining vehicles we classified as "large" SUVs.

Some of you may take issue with our lumping Jeep Grand Cherokees and Chevy Suburbans together, but since we on Hogback Road have never been enamored with the semi-trailer wannabes that are the current fashion in certain sybaritic suburban circles, this categorization forces the SUV behemoths to display extraordinary virtue if they are to overcome the driving disadvantages inherent to their jumbo size.

Since we wanted to avoid evaluating every representative from each of the 97 truck models for these inaugural selections, we held a nominating meeting to generate five candidates for each category. A bit of inflation, along with our unwillingness to eliminate some mechanical twins (Ford Escape/Mazda Tribute) at the nominating stage, resulted in a total of 35 nominees, of which 30 showed up for our evaluation.And the Winners Are:

Luxury SUV: Acura MDX
Small SUV: Ford Escape
Large SUV: Toyota Highlander
Pickup: Chevrolet Silverado
Van: Honda Odyssey

Following the same procedure we use for our 10Best program, we assembled the nominees at our secret facility west of the Ann Arbor headquarters, gathered up our entire domestic staff, and spent three days driving, examining, and arguing about our favorites. We then scored every vehicle on a scale of 100.

Acura's first built-in-house SUV (the late SLX was simply a rebadged Isuzu Trooper) arrived here last year with a terrific combination of utility, luxury, and performance. It promptly won a comparison test in the December 2000 issue and has now copped our first-ever Best Luxury SUV honor.

Whether you are hauling people, sheets of plywood, lengths of pipe, or cases of beer, the MDX offers more capacity than any other SUV short of the behemoth class. And its slick-folding third row of seats provides excellent versatility in this voluminous package.
Motivation is provided by a 240-hp V-6 that can slingshot the MDX from 0 to 60 mph in 8.4 seconds. That's quick enough to dust off all its V-6 competitors and several eight-cylinder luxo SUVs as well.

Although the MDX's four-wheel-drive system and minivan-based underpinnings can't deliver heroic performance in the woods, this Acura displays carlike moves and comfort on suburban highways where its owners will roll up the overwhelming majority of its miles.
At a base price of $34,850, with leather seats and a full range of comfort and convenience options, the MDX is easily the bargain of the class, and the standout winner of the category.
Vehicle type
front-engine, 4-wheel-drive, 7-passenger, 5-door wagon
Base price
Engine type
SOHC 24-valve 3.5-liter V-6
Power (SAE net)
240 bhp @ 5300 rpm
5-speed auto
106.3 in
188.5 in
Curb Weight
4350-4400 lb
EPA fuel economy, city driving
17 mpg

Crash Results:


6,809 Posts
Discussion Starter #2
Motor trend review

Driver & Professional Reviews

MT's 2002 Sport/Utility of the Year packs a lot of room, value, and performance for its price range. Not a hard-core off-roader, it's designed to handle light-duty off-road excursions without compromising on-road comfort, safety, and handling agility. With its third-row seat, the MDX can accommodate seven passengers, and that seat ingeniously folds flat to create cavernous luggage space. Its 3.5L/240-hp V-6 sends power to a five-speed automatic transmission and then a full-time AWD system that can redistribute torque to those wheels with the best grip. Four-wheel discs with anti-lock, leather interior, and an in-dash CD audio system are standard.
Source: Motor Trend
The Acura MDX is where mainstream sport-utility vehicles are headed. Unlike old-style SUVs, the MDX was not adapted from a pickup truck chassis but instead was developed from the Honda Odyssey minivan platform. Instead of sitting atop a heavy steel frame, the Odyssey uses unibody construction for lighter weight. With its more carlike suspension, the MDX provides a smoother ride than most truck-based SUVs. It's also easier to get into and out of, yet it still provides a raised seating position. The MDX's standard all-wheel-drive system is always on duty, and the driver can engage a differential lock to help get the vehicle unstuck from mud or snow. (There is, however, no low range for steep, off-road descents.) The Acura system is easier to use and more appropriate for the kinds of situations most people will encounter. The Acura's spacious cabin is also user-friendly, with a standard third-row seat that allows seven people (including the driver) to come along for the ride. Both the third- and second-row seats fold flat to provide more than 80 cubic feet of cargo space. A 240-hp V-6 with a five-speed automatic transmission provides smooth power. Like those of most other Acuras, the MDX's standard equipment list is long, and its options list is short. A touring package includes a roof rack, an in-dash CD changer, and alloy wheels. A navigation system is also offered. The MDX is an excellent choice for the family that will use its SUV as a car.
Source: Automobile Magazine

100% Recommended (2 reviews)
Reliability: 5.0
Seat Comfort: 5.0
Quality and Craftsmanship: 5.0
Handling And Control: 5.0


A customer's view:

02 MDX
Pros: Versatile, spacious, car-like ride, loaded with options
Cons: Price not negotiable, dealers think it's gold, limited availability, waiting
The Bottom Line: If you can afford to wait and can afford to pay, go for it. Expect poor treatment from the dealer and expect great treatment from the car.
Recommended: No

I just brought my base MDX home yesterday after a 5 month wait. I chose a base model because it comes loaded with amenities that are usually options on other SUVs. The only other major options are the Touring package and the Navigation system. Each will add about $2k to the price of the car so a fully decked out model will run about $40k. I don't think the navigation system is worth $2k. And I don't think the Touring package is worth $2k for options that are slight and few.

The other SUVs I considered were the MB ML320, the BMW X5, the Lexus RX300, the Infiniti QX4, and the Land Rover Discovery. I did detailed research of each SUV and here are my (brief)personal findings:

- MB ML320: Very truck like and suspect reliability. I have a MB E320 sedan and the M-class does not warrant to be a MB. It's truly a wannabe MB that doesn't come close. That explains the relatively competitive price.

- BMW X5: Safest and best handling/performing but not an SUV. It's an SAV as they call it and it may look big front the exterior but is actually smaller on the inside than the Honda CRV. This vehicle is purely for driving pleasure. Forget about functionality and space.

- Lexus RX300: This is merely a Camry wagon with a higher roof. Top-notch reliability but not that roomy. Drives much like the...Camry! It should since it's built on the Camry platform, as is the Lexus ES300. This is also the same as the Toyota Highlander with less luxury.

- Infiniti QX4: This is the Nissan Pathfinder with luxury features. Aesthetically, it looks slightly better than the Pathfinder. This is a good option for those who like Nissans/Infinitis so long as you can get a good price. Figure paying what you would for a loaded Pathfinder but a little more for those extra options unfounded on the Pathfinder.

- Land Rover Discovery: The has the most off-road capabilities but most of us drive SUVs on-road. Sluggish engine for a V8 that guzzles gas. Roominess is not that great but not that bad. Reliability is questionable and expensive.

- Acura MDX: Roomy, versatile, good power, good gas mileage, reliable, safe, has three rows of seats, 2 rows of seats fold flat. This is a Honda Oddessey SUV. The Oddessey is hands-down the best Minivan and Acura built the MDX on the Oddessey platform to make it the hands-down best SUV.

Based on my reviews, it's obvious why I chose the MDX. The only drawback is the buying experience. I believe Acura is creating heightened demand by limited supply but it may be backfiring. In the months that I waited, I was tempted on several occasions to buy something else. And luckily I could afford to wait with two cars already. Not only is waiting a hassle, the dealers are very arrogant in selling this car. No price breaks and in some cases, there is mark-up. The attitudes of the salesmen is really disgusting. They are like the "car Nazis" of Seinfeld. Get in line and take a number because they treat you like a number, not a person. Despite the retail price, it is still well-equipped and a relatively good value. But it still doesn't mean that the dealer can move a little on the price.
Owns this vehicle: Yes
Amount Paid (US$): 35350
Condition: New
Model Year: 2002
Model and Options: Base


160 Posts
Good job Paul!

That's why I chose the MDX. My wife was looking into getting a Land Rover but I convince her that they're not reliable and gas guzzler. I told her Japanese engine are the way to go when it comes to reliability.

143 Posts
Toyota LARGE SUV? I'm scratching my head over that one:confused: :confused: .....

15 Posts
Well the 2002 Consumer Reports rated the Rx300 very highly, and went on to say that if you want the Rx300 quality but don't need the Lexus price tag or name badge, then the Highlander was definately the way to go.
They also rated the MDX very highly; it was also one of their recommended picks.
I guess on paper the Highlander might sound good, but in real life, comparing it to the MDX is like comparing apples and oranges. Acura is a different class.

6,531 Posts
Thanks for the info ...

... but I can not call it a truck:cool:

Call it an MDX, a car. an SUV, a vehicle, the X, whatever ... but please not a truck.:eek:

206 Posts
What happened to the Envoy? Not listed? I considered buying one. Sure glad I waited for the MDX.

15 Posts
In addition to considering the RX300 and the QX4, the Envoy/Trailblazer did catch my eye.
However, after looking at the crash test results (both gov't and IIHS) I moved on. While I wasn't shopping around based on safety, it was a consideration; why would I knowingly buy something that I knew to be substandard?
Hey, while I have no beef with Chevy (I also have a Monte Carlo), there is no way in hell I'm dropping almost 40Gs (including tax) on a Chevy Trailblazer LTZ. In the end, it's still a Chevy.
(Although in the their defense, they offer STANDARD (LTZ model MSRP @ 33,500 - 34,000) a full size spare, power passenger seat, turn signal mirrors, dusk sensing headlamps, OnStar, seperate rear audio, memory seats and windows, opening tailgate window, towing package, cargo net, automatic dimming driver's side mirror, one touch front windows, and an optional one touch moonroof) And no waiting.
Well, I keep consoling myself that it only looks good on paper. Well, at least I'll be safe.....................maybe I should think this over.

6,809 Posts
Discussion Starter #9
More info.

Since its introduction in the fall of 2000, the Acura MDX luxury sport utility vehicle has redefined the luxury SUV segment, combining performance and handling with a long list of standard luxury features, ultra-low emissions and a smooth, sedan-like ride. The 2002 MDX continues to set the standard, building on the combination of power, style and handling that resulted in its being named Motor Trend magazine's 2001 Sport/Utility of the Year and the 2001 North American Truck of the Year.

"In the year since its introduction, the MDX has quickly become the benchmark for the luxury SUV class," said Dick Colliver, executive vice president, sales. "It provides a unique combination of rugged SUV performance, sedan-like handling and a luxurious yet extremely functional interior."

The MDX's 3.5 liter, 24-valve, all-aluminum, SOHC engine produces 240 horsepower and 245 lb.-ft. of torque, for ample power both on-road and off. Standard features include an electronically-controlled, five-speed automatic transmission and an innovative VTM-4 four-wheel drive system that proactively apportions torque from the front to the rear wheels before wheel slippage can occur. The MDX meets California's stringent Ultra-Low Emissions Vehicle (ULEV) standards and, with estimated city/highway ratings of 17 mpg city/23 mpg highway, it delivers better combined fuel economy than any of its luxury competitors.

In addition to ample power, the MDX also delivers sedan-like handling and a smooth, compliant ride. Power steering, 4-wheel fully independent suspension, 4-wheel disc brakes with 4-channel ABS, standard 17-inch alloy wheels and specially designed P235/65R-17 all-season tires provide stability and responsiveness. Front and rear stabilizer bars, a wide track and a low center of gravity give the MDX predictable cornering response and maximum cornering traction.

While the MDX is already one of the most refined SUVs, the 2002 model gets a host of enhancements that result in an even quieter ride. To further reduce interior noise, the MDX receives new diffuser side mirrors, a sound-absorbing roof lining, thicker windshield glass and a layer of Thinsulate' insulation in key areas throughout the interior.

Externally, the MDX strikes a balance between muscularity and elegance. Acura's signature family grille and bright, clean headlight treatment highlight the sharply chiseled front fascia while a wide stance communicates a message of strength and stability.

The MDX's interior emphasizes the vehicle's versatile yet refined character with standard-setting levels of luxury and functionality. A uniquely transformable interior with three rows of seats allows the MDX to comfortably seat up to seven passengers. Second and third row seats split and fold flat into the floor providing 82 cubic feet of cargo room. Even with all three rows in use, MDX still offers 14.8 cubic feet of cargo room behind the third row seats.

The comprehensively equipped MDX comes standard with a host of luxury features including a seven-speaker AM/FM/Cassette stereo with in-dash CD player; a multi-function digital trip computer and the world's first synchronized climate control system. Standard safety features include a dual-stage passenger's front airbag that adjusts deployment force to one of two rates according to the severity of the impact and seatbelt use; driver's and front passenger's side airbags with exclusive occupant position sensors in the passenger's seat; and the LATCH (Lower Anchors and Tethers for Children) system on the second row of outboard seats.

An optional Touring Package adds additional features including a roof rack, exclusive alloy wheels; and an upgraded 200-watt, eight speaker Acura/Bose Music System with 6-disc, in-dash CD changer, front passenger's 8-way power seat, drivers seat and outside door mirror memory system and Michelin Cross Terrain tires.

The Acura Satellite-Linked Navigation System is offered as a factory-installed option. One of the most sophisticated, yet easy-to-use, navigation systems on the market today, the Acura Satellite Linked Navigation System contains mapping of the continental United States and a nationwide directory of 3.7 million points of interest.

Like all Acura vehicles, the MDX comes equipped with a comprehensive 4-year/50,000-mile limited warranty that includes Acura's TLC (Total Luxury Care) customer service package.

For more information about Acura vehicles, please visit For media inquiries, please go to

6,809 Posts
Discussion Starter #10

Acura Announces Pricing For 2002 MDX Luxury S

Torrance, Calif. 10/23/2001 -- The 2002 Acura MDX luxury SUV will be priced at $34,700 when it goes on sale today at Acura dealers nationwide. The MDX is available with only two factory options: a luxury Touring Package priced at $2,600 and the Acura Satellite-Linked Navigation System priced at $2,000. MDX prices represent a $330 increase compared to last year or a 0.9 percent increase based on a sales-weighted average.

Acura's award-winning MDX sport utility vehicle features a 3.5-liter, 240-horsepower V-6, a 5-speed automatic transmission, the innovative Variable Torque Management 4-wheel drive (VTM-4) system and three rows of seats. The 2002 model receives a variety of subtle enhancements including redesigned "diffuser" side mirrors and thicker windshield glass, both of which help to reduce wind noise; an intermittent rear windshield wiper; and the Lower Anchors and Tethers for Children (LATCH) child seat restraint system.

Since its introduction in October of last year, more than 30,000 MDXs have been sold, helping Acura set a 2001 model-year sales record of 165,983 units.

2002 Acura MDX Highlights:


240-horsepower, 3.5-liter, 24-valve, SOHC, V-6 aluminum alloy engine
VTEC(TM) (Variable Valve Timing and Lift Electronic Control)
VTM-4(TM) Four Wheel Drive System
Programmed Fuel Injection (PGM-FI)
5-speed automatic transmission
Meets Ultra Low Emissions Vehicle (ULEV) standards
105,000 mile tune up interval

4-wheel fully independent suspension
Variable power-assisted, rack-and-pinion steering system
17-inch alloy wheels with all-season, high performance tires
4-wheel disc brakes with Anti-lock Braking System (ABS)

Flexible three-row, seven passenger seating
Synchronized automatic climate control system
Leather trimmed seating (first and second row)
Power moonroof
Heated front seats
8-way power driver's seat
Trip computer
Premium music system with in-dash CD changer
Keyless entry system with anti-theft engine immobilizer
Optional Acura Navigation System
Optional Touring Package including roof rack, remote memory driver's seat and outside windows, Acura / Bose Music System
Pricing for 2002 Acura MDX

Touring Package
Acura Navigation System


Destination and handling charge

6,809 Posts
Discussion Starter #11
Quality issues

2002 Acura MDX -- Quality and Maufacturing

Like all Acura products, the MDX benefits from an integrated approach to designing manufacturing quality into the original plan for the vehicle. This approach results in a vehicle that is sure to achieve the legendary durability, quality and reliability that is the hallmark of all Acura vehicles. To achieve the specified targets for quality, the MDX team had to carefully consider the logical assembly of components as well as the effects of time and wear on each part and system.

The development team conducted testing on three continents and covered thousands of miles of testing varying from bitter cold to sweltering heat, adding in variables of high and low altitude environments, with full loads and a battery of tests that left nothing to chance. These tests confirmed that MDX will perform at its impressive levels for years to come.

The following are a few of the many areas that show the attention to detail that typifies the design and engineering behind the MDX.

A quiet interior is essential to any high quality vehicle. Towards that end, MDX engineers incorporated a host of design features and refinements aimed at blocking NVH from the passenger cabin.

All powertrain-related hardware is double isolated from the main body structure by use of rubber mounting systems. A perimeter-type front subframe supports the engine, transaxle, steering, and front suspension lower control arms. Two engine mounts are hydraulic designs with internal damping to provide excellent isolation throughout the broad range of excitation frequencies. An assortment of tuned-mass dampers attached to both the engine mounts and the subframe counteract resonance. A dual-path upper mount is used between each front spring and strut unit and the body structure.

The front axle half-shaft inner joints are designed with internal rollers that minimize friction. A two-piece tubular propeller shaft is used to transfer torque with no susceptibility to whip or vibration. A dynamic damper positioned inside the front tube is tuned to cancel out vibration at cylinder-firing frequencies. The rear drive unit is supported by three rubber mounts in a second subframe, which is in turn attached to the body structure through four widely spaced rubber mounts. Rear coil springs are insulated from both the body and the rear suspension hardware by means of upper and lower rubber pads.

Various fuel tank subsystems - the fuel vapor canister, the assembly, and the ABS modulator - are rubber isolated from the body to block any sympathetic NVH contribution.

The engine's high volume intake and exhaust systems are engineered for non-restrictive but quiet flow of fluids through the engine. Just aft of the point where left- and right-bank exhaust flow join, a corrugated flex pipe is positioned to permit quiet movement between the engine and the remainder of the exhaust system. A large pre-chamber muffler near the middle of the vehicle is glass-filled to absorb high-frequency exhaust noise. The high-volume silencer near the rear bumper has dual outlets to ensure exhaust flow requirements during full throttle acceleration.

Extensive sound deadening is used within MDX's body structure. Melt sheets - a mixture of asphalt and reinforcement material that bonds to surfaces in the paint ovens - cover virtually the entire floor of the vehicle from the vertical dash panel to the liftgate sill. For 2002, an acoustic roof lining runs from front to rear while additional sound-deadening material blankets the dash panel and the rear of the hood. Molded rear fender liners help quiet road splash and tire noise. To create a noise barrier at the base of the A, B, and C pillars, expanded foam fills these cavities. This foam is expanded by the heat of the paint-curing ovens, noise from the floor area is blocked from being transmitted inside the pillar cavities to the interior compartment.

Special recycled textile absorption blankets are attached to the underside of the instrument panel and the sides of the center console.

Design of the door mirrors is especially sensitive to wind noise. For 2002, the MDX receives diffuser side mirrors that smoothly channel air between the mirrors and the window glass for reduced wind noise. Sponge material between the base and the door surface eliminates the possibility of gaps in that area. The molding to base interface is also a zero-gap design.

Additional weatherstrips are positioned in critical window frame to pillar gaps to help maintain smooth air flow down the side of the vehicle.

The bottom line is a net lack of road, powertrain, and wind noise inside the passenger compartment. In competitive tests, MDX is comparable with the best luxury-class SUVs in overall NVH performance.

The all-new Acura MDX is the first sport utility vehicle designed with a no compromise engineering philosophy. MDX delivers fresh styling, unmatched versatility, car-like driving exhilaration, class-leading safety and environmental responsibility while also upholding Acura's well established reputation for outstanding value. Acura customers expect best in class quality. Towards this end, MDX has the refined attention to detail lacking in several of its luxury SUV class competitors.

Body gaps are best in class by an impressive margin. Exterior design is clean, functional, and well proportioned. Adornments are elegant and tasteful. Door jams are neatly finished. MDX sets a new standard for quality craftsmanship in its class.

MDX's pull-type door handles are chrome plated for a luxury look and feel. Clearance pockets behind each release handle are generously sized to provide room for gloved hands and to avoid ring and fingernail scratches.

To minimize construction tolerances, MDX's doors are attached to the car by rigid bolts that pass through zero-clearance hinge holes. Doors are made of high-strength, galvanized steel for dent resistance. Front mudguards are provided to deflect rocks and debris and rear mudguards are available as dealer-installed accessories. Lower door surfaces are painted with a soft primer that is especially resistant to stone chips. Seals that extend from the lower edges of the doors to the sill area block the build up of dirt and debris that might otherwise soil clothes during entry and exit from the vehicle.

Panel gaps are consistently tighter than comparable dimensions seen in competitive makes. For example, MDX's hood-to-headlamp gap is less than a third of what is common in the Mercedes ML320 and less than half the width of the Lexus RX300's gap. Most MDX gaps are between 0.12- and 0.18-inch compared to 0.18- to 0.3-inch in the Lexus and 0.2- to 0.37-inch in the Mercedes. To permit a tighter fit between rear quarter window and the adjacent quarter panel, a beveled edge is used on the glass.

Seals and covers are positioned in door jams and sill areas to mask assembly welds. In the liftgate opening, the trim has a clean appearance that's not marred by the visible bumper clips used by some competitors. All interior trim is retained with hidden fasteners. Front and rear wipers are smooth, single-piece designs for a clean look.

Door mirrors have blue-tinted glass to cut glare at night. Electrical heating grids can be activated by a switch near the remote mirror control pad to clear frost and fog from the mirror surface.

Side and rear window glass is deeply tinted for privacy and to keep the interior cooler during summer months.

The MDX is built at Honda of Canada Manufacturing in Alliston, Ontario, near Toronto.

6,809 Posts
Discussion Starter #12
Safety issues

2002 Acura MDX -- Safety

The Acura MDX SUV is engineered to meet and often exceed all applicable safety standards. Safety, security, and accident avoidance are top Acura priorities. With that in mind, various systems - body structure, chassis, driveline, passenger restraints - interact positively to help the driver steer clear of hazards whenever possible and enhance occupant protection in the event an accident is unavoidable.

An innovative Variable Torque Management (VTM-4) all-wheel-drive system is the key to sure-footed handling and straightforward controllability whether the pavement is dry or wet and slippery. Combined with MDX's four-wheel independent suspension, torque sensing power rack-and-pinion steering, and four-wheel-disc brakes with ABS, VTM-4 delivers best-in-class traction to enhance the driver's ability to guide an MDX safely out of harm's way.

To help safeguard occupants from injury when a collision is unavoidable, MDX provides multiple layers of protection. The computer-engineered body structure features front, side and rear crumple zones, a high resistance to offset and side impacts, and a well protected fuel tank. Extensive use of high-strength steel yields a robust safety cage surrounding passengers without incurring an awkwardly heavy curb weight.

All seating positions have three-point seat belts. Front seat belts are equipped with pretensioners and automatic load limiters that are activated in certain collision conditions. The MDX comes with standard driver's and passenger's front air bags. The dual-stage passenger's front air bag can deploy at the most appropriate of two rates depending on the severity of the crash. In addition, if the driver's or passenger's seat belt is not fastened, the air bag deploys at a lower collision speed to help offer more protection to the unbelted occupant.

The driver's and front passenger's seats also feature side air bags mounted in the seat bolster closest to the door. The passenger's seat is equipped with a system designed to disable side air bag deployment and prevent injury to a small child (or small-statured adult) if they lean into the side air bag deployment path. Once the child returns to an upright seating position, the side air bag will reactivate so it can deploy and protect the child in a side impact.

MDX engineers used powerful computers to assure that this vehicle's safety cage structural design would perform well even before physical prototypes were built. Crash simulations helped reveal areas of the design that needed more - and sometimes less - reinforcement to absorb energy while resisting intrusion.

MDX has an especially robust floor construction to optimize both rigidity and resiliency. Two longitudinal rails run continuously from bumper to bumper. The rails are buttressed by a total of eight box-section crossmembers and two bumper bulkheads. This provides the strength needed to resist standard barrier impacts at the front and rear, offset crashes (wherein most of the load is applied longitudinally to one corner of the vehicle), and side impacts.

A four-ring shell-type safety cage is used to help protect occupants with A, B, C, and D pillars that run continuously to avoid intrusion during side impacts. To meet 2002 federal head-impact requirements, roof-pillar trim and headliner materials absorb energy and help reduce the likelihood of occupant head injury. Stiffeners inside the doors at the beltline provide a continuous horizontal connection between the first three pillars. Tubular beams are welded inside the doors at wheel height to provide additional intrusion resistance.

One quarter of the body structure - longitudinal rails, floor crossmembers, pillar reinforcements, and bumper beams - is made of high-tensile steel for maximum strength with minimal weight. Acura has applied for a patent on the roof-mounted reinforcement used to secure the second-row-center passenger's seat belt.

MDX's fuel tank is made of highly puncture resistant,six-layer,high-density molded-polyethylene. It is located ahead of the rear axle and for protection, high-strength, box-section floor reinforcements help guard it from side collision damage.

The bottom line is best-in-class collision performance. Based on internal simulation and testing, the MDX is expected to earn five stars in federal government New Car Assessment Program (NCAP) frontal barrier tests and Side Impact (SINCAP) tests. A good rating is expected from the Insurance Institute for Highway Safety's offset barrier tests.

Unlike some SUVs, MDX provides a three-point restraint system for all seven seating positions. A special roof-mounted reinforcement, positioned between the C and D pillars, serves as a rigid mounting point for the second row, middle passenger's shoulder belt.

Front seat belts are equipped with pretensioners and automatic load limiters that are activated in conjunction with the front air bags. The MDX comes with standard driver's and passenger's front air bags. The dual-stage passenger's front air bag can deploy at the most appropriate of two rates depending on the severity of the crash. In addition, if the driver's or passenger's seat belt is not fastened, the air bag deploys at a lower collision speed to help offer more protection to the unbelted occupant.

Like other Acura products, MDX is equipped with seat-mounted side air bags to help safeguard the driver and front passenger from side-impact injury. An innovative occupant position detection system is used to assure that the passenger's side air bag has a clear path for deployment. In the event a child (or a small-statured adult) leans into the deployment path of the side air bag, a seven-segment antenna system built within the backrest signals this condition to an electronic control unit (ECU) also located within the seat. The ECU then deactivates the side air bag from functioning and triggers a "SIDE AIR BAG" indicator light in the instrument cluster. After the front occupant returns to a normal seating position, the side air bag module automatically resumes full-functional status.

MDX has a standard keyless-remote entry system that locks and unlocks all doors and the rear hatch at the push of a button. To enhance theft protection, only one key lock mechanism is provided for the driver's door position. The same key fob used to lock the doors also activates the MDX's security system. In response to any attempt to enter the vehicle without the key fob or ignition key, the horn sounds, and the flasher lamps are activated. If need be, the alarm system can be triggered to summon help by depressing a "panic" button on the remote-keyless fob.

Imbedded within MDX's ignition key is an electronic microprocessor circuit that communicates with a receiver in the ignition switch to enable the vehicle's electrical systems. Forcibly vandalizing the ignition switch, hot-wiring, or attempting to start the car with a key lacking the microprocessor circuit will result in immobilization. Without proper key-to-immobilizer communication, the MDX will simply not start.

For 2002, the Lower Anchors and Tethers for Children (LATCH) system has been added to the second row of outboard seats. The LATCH system features ready-to-use tethers imbedded at the top and bottom of the seats allowing compatible child safety seats to be installed without using the vehicle's seat belt system. The LATCH system increases child safety by reducing shifting of a compatible child seat while the car is in motion.

6,809 Posts
Discussion Starter #13

2002 Acura MDX --

The Acura MDX was the first product in an uncharted portion of the market: a car-like, family-sized, luxury SUV. To venture beyond current competitive offerings with a no-compromise design, a new chassis was essential. Engineered to deliver the exhilarating driving experience and the outstanding vehicle dynamics expected of Acura products, MDX exceeds conventional SUV chassis design standards by a wide margin.

Key design elements selected to meet ambitious driving dynamics goals are as follows:

Extra-wide track dimensions
Short wheelbase for agility
Rubber-isolated front and rear subframes
Independent front and rear suspension systems with car-like geometry and long wheel travel for sporty handling and a comfortable ride
17-inch cast-aluminum wheels
All-season, radial tires with silica tread compound for excellent traction and fuel economy
Four-wheel disc brakes with four-channel ABS and electronic distribution
Torque sensing rack-and-pinion power steering
MDX has a wide track - 66.3-inches front, 66.5-inches rear -to optimize handling precision, stability, and ride comfort. The strut-type front suspension provides a generous 7.3 inches of wheel travel (4.3-inches in compression, 3.0-inches in rebound) with a moderate spring rate and relatively firm damping. Separate load paths to the unit body are provided for the coil spring and the shock absorber to facilitate tuning out road noise. A solid 0.9-inch stabilizer bar is linked directly to the strut via ball-joint connections to resist body roll during cornering maneuvers. The small 0.04-inch scrub radius designed into the front suspension is unusual for SUVs but this feature gives the MDX car-like steering response and handling that's consistent and predictable in on- and off-road situations. Accelerating or hard braking with uneven traction underfoot does not cause MDX to drift off line as is the case with many SUVs.

A low roll center (6.2-inches above the ground) further improves MDX's handling. The lower control arm bushings are designed to provide a stabilizing toe-out steering effect when loaded during braking or cornering. The L-shaped arm allows a very tight steering lock for good low-speed maneuverability. In fact, the Acura MDX's turn-circle diameter is a modest 37.2 feet, some four feet tighter than the Lexus RX 300's turning circle.

The MDX's engine, transaxle, transfer case, steering gear, and front suspension are all supported by a welded-steel subframe secured to the unit body's longitudinal rails through four tuned rubber isolation mounts. The front of the subframe assembly is tubular for maximum stiffness with minimal weight. A stiffener located under each subframe attachment fastener helps stabilize the assembly, thereby sharpening handling and braking performance. A stiffener plate bolted across the subframe under the transfer case greatly increases the assembly's rigidity. Two dynamic and one mass damper are positioned to counteract noise and vibration, while two fluid-filled engine mounts quell vibration at idle and isolate powertrain NVH from the passenger compartment. The steering gear mounts are made of heat-resistant rubber to provide good vibration isolation, the firm retention necessary for sensitive on-center-steering feel, and life-of-the-vehicle durability.

MDX's steering system is tuned for quick, linear, car-like response and sensitive feel - and the torque sensing, power steering assist is high for parking maneuvers and low at highway speeds.

The MDX's rear suspension is a compact, multi-link trailing arm layout for excellent ride and handling, minimum weight, and optimum packaging. Wheel travel is a generous 4.9 inches in compression and 3.3-inches in rebound. The three links that position each rear wheel laterally run between the knuckle assembly and the subframe. A trailing arm also runs from the unit body to each rear knuckle. Coil springs seat on the lowermost lateral link and anchor against the unit body directly behind each axle shaft. Shock absorbers, positioned ahead of the drive shafts, run from a low point on each knuckle to a secure attachment point on the unit body. Knuckles are an "in-wheel" design to optimize suspension geometry and packaging efficiency. Bushing compliance provides a modest toe-in effect in response to substantial cornering and braking loads to enhance dynamic stability. A solid 0.8-inch anti-roll bar helps keep the body relatively flat during hard cornering. The rear roll center is positioned at a 6.7-inch height to provide linear and predictable behavior at the limit of adhesion. The results speak for themselves, as MDX truly sets a new standard for ride and handling in the luxury SUV category.

Packaging of major components at the rear of the MDX is a major engineering challenge. The rear subframe, which supports most of the rear suspension and the rear axle drive unit, is made of high-strength steel for high stiffness and minimal weight. The shape of the rear subframe is equally important - it must accommodate the drivetrain components for the VTM-4 four-wheel drive system, the multi-link rear suspension pieces and still allow the versatility of the third-row seat and flat cargo floor. For excellent ride and handling characteristics, the subframe attaches to the unit body at four widely spaced, rubber-isolated mounting points. Rear-suspension components, especially the springs and shock absorbers, are as compact as possible to facilitate a wide, flat load floor and to leave room for both a spare tire and a full-size fuel tank. The rear axle drive unit is mounted to the subframe by means of rubber isolators to block road and powertrain noise and vibration from the passenger compartment. A tuned dynamic damper attached to the drive unit cancels propeller-shaft and drive-shaft vibration.

Two different die-cast aluminum wheels are offered for the MDX. Both have 6.5-inch-wide by 17-inch diameter rims, a 45mm offset dimension, and five-lug bolt pattern. Large openings in the wheels provide ample brake-system ventilation. Tires supplied by Michelin and Goodyear are both sized P235/65R-17 and carry an M+S (mud and snow) label and a T (118 mph) speed rating. Both the tread and the carcass were designed with computer-aided tools to achieve excellent ride comfort, low noise and wear, and best-in-class all-weather performance. Tread materials are compounded for excellent winter traction and include silica for low rolling resistance. During cold weather engineering tests, the MDX's tires consistently outperformed some of the most highly rated snow tires on the market.

The compact spare tire is carried under the rear load floor and can be lowered by turning a hidden hex-head bolt with the provided lug-nut wrench. The hex-head bolt is located under a cover conveniently located in the rear hatch trim area. This arrangement guarantees the security of the spare and keeps it readily accessible without disturbing luggage or cargo carried onboard. Room is provided to stow a flat or a full-size spare in the compact spare's location. Corrosion and failure of spare tire retention equipment, a common problem in some competitor SUVs, is avoided by use of stainless steel and polymer materials eliminating high-mileage failure.

6,809 Posts
Discussion Starter #14


MDX is equipped with state-of-the-art, four-wheel disc brakes and a Bosch 5.3 four-channel Anti-lock braking system. The brake system hardware is tuned for quick response, low effort, and short pedal travel. For optimum performance with widely varying loads - including the possibility of towing - the MDX features an innovative Electronic Brake Distribution system (EBD). At the rear, a select-low braking strategy is used to preserve directional stability in slippery driving. In the event one rear wheel verges on lock-up, triggering a pressure modulation at that wheel, brake pressure is also diminished at the adjoining wheel to preserve the rear axle's lateral stability.

Extra-large brake rotors and calipers provide the capacity necessary for short stopping distances and excellent fade resistance - even with a heavy load in tow - and the precise pedal feel expected of an Acura. The vented front rotors are 11.8-inches in diameter and 1.1-inches thick. Solid drum-in-disc rear rotors are 12.3-inches in diameter and 0.43-inch thick. A drum-type parking brake mechanism is positioned within the inner portion of the rear rotor. Parking brakes are both set and released by stepping on a pedal, freeing space in the console area. The tandem-type vacuum booster consists of two 9-inch diameter booster chambers.

MDX brake components are large in capacity to help handle heavy loads - both those carried on board and those towed behind. Front-to-rear brake effort proportioning is electronically regulated. The Anti-lock Braking System (ABS) has four sensing and activating channels to detect a wheel on the verge of lock up. In the event this occurs, brake pressure is held, then reduced, to permit that wheel to regain traction before full braking resumes. A select-low strategy controls the braking effort at both rear wheels as soon as one nears lock up to safeguard lateral adhesion and to help avoid any tendency to spin or fishtail during hard braking.

MDX's ABS is especially effective at maintaining a straight heading on split-friction surfaces where one track encounters snow or ice while the other rolls on dry pavement. The front suspension geometry has a very small scrub radius to help keep the MDX running true even when one front wheel is braking harder than the other because of uneven traction conditions.

Low-profile Goodyear and Michelin radial tires provide outstanding adhesion. During dry pavement handling tests, MDX demonstrates significantly higher cornering grip than other luxury SUVs. As cornering forces rise, understeer is mild and linearly progressive to accentuate predictability. The power-assisted, rack-and-pinion steering is tuned for on-center sensitivity and slack-free response. Consistent with the desire to provide a rewarding driving experience, MDX's overall steering performance is best-in-class.

The 19.2-gallon, saddle-shaped fuel tank is molded of high-density polyethylene for low weight, freedom from corrosion, and impact resistance. It's positioned immediately ahead of the rear wheels and over the propeller shaft to help guard against collision damage. Corners of the tank are rounded and the inside of the tank is baffled to diminish the likelihood of sloshing-fuel noise. The polyethylene filler pipe and fuel lines are light, not susceptible to corrosion, and resistant to fuel vapor losses. A high-efficiency fuel pump is housed inside the fuel tank. The fuel-filter is a lifetime design that never needs replacement.

MDX complies with all evaporative emissions, on-board diagnostics, and refueling vapor recovery requirements. The fuel vapor canister and filter are rubber mounted for noise isolation and protected against rock and debris damage by a deflection shield.

The ability to haul pop-up campers, medium-sized boats, and recreational vehicle trailers is high on the priority list for many SUV owners. To understand this facet of the MDX's makeup, MDX engineers polled focus groups and studied survey results that tapped 200,000 households. Their findings offered the insights needed to properly outfit the MDX to surpass the towing expectations of most customers. Engineers learned that roughly one third of the six-cylinder-powered-SUV owners expect to tow something at one time or another. In addition, 18-percent tow more than four times per year. Approximately 10 percent of the miles accumulated on six-cylinder SUVs are with a trailer in tow.

Another notable discovery was that many customers aren't particularly knowledgeable about towing technicalities. Terms like "gross axle weight" may be germane to the engineering process but such language can leave average customers in a state of bewilderment. This realization convinced engineers that customers' interests are best served by load ratings that are both realistic and easy to comprehend.

Ultimately, the engineers concluded that a casual or weekend towing capability was most appropriate for MDX. Customer feedback helped set the towing limit at 4500 pounds for boats and 3500 pounds for other types of trailers. A heavier load is acceptable with boats because their pointed bow shapes impose less aerodynamic drag on the towing vehicle than a slab-faced, square-cornered trailer.

Industry practice is to boast a high maximum tow rating, even though some sacrifice of passengers and cargo may be necessary to suitably accommodate such a trailer load - in some cases limiting the vehicle to one passenger to accommodate the maximum specified towing capacity. The Acura MDX's 3500/4500-pound rating is calculated to include up to four passengers and their cargo.

To help ensure that customers will be able to move a maximum rated load up a grade from rest (such as pulling a loaded boat trailer up a launch ramp), engineers sought out the most challenging entry roads and launch ramps in the country. Through testing, they verified that MDX proficiently handles the 17-degree (31-percent) grades on mountain roads approaching Lake Cumberland in southern Kentucky and the strenuous combination of 15-degree (27-percent) grades and 5280-foot elevation at Lake Tahoe. A note in MDX's owner's manual suggests reducing gross combined weight two-percent for every 1000 feet of elevation. At sea level, MDX can move a 4500-pound boat and four passengers up an 18-degree (32-percent) slope.

In support of safe towing, MDX's tow hitch and other hardware needed for the job are factory engineered for dealer installation. The dealer-installed trailer hitch is a Class III receiver-type design that bolts on with no drilling, cutting, or bumper-cover modifications. An external transmission cooler and a separate power-steering fluid cooler is also included along with a harness to provide electrical power to trailer lights plugs into a connector provided at the rear of the vehicle.

6,809 Posts
Discussion Starter #15

2002 Acura MDX -- Powertrain -- Part 1

An advanced powertrain is essential to meet MDX's primary goals of outstanding performance, class-leading low emissions, and excellent fuel economy. To that end the MDX is powered by an advanced 3.5-liter, V-6, VTEC engine that delivers 240 horsepower at 5300 rpm and 245 lb.-ft. of torque from 3000 to 5000 rpm. Acura's renowned Variable Valve Timing and Lift Electronic Control (VTEC(TM)) valvetrain, first used in the NSX supercar, adjusts the timing, duration, and lift of the intake valves according to engine speed. In conjunction with a two-stage intake manifold, VTEC yields high peak-rpm performance, muscular response at low- and medium-rpm, very low emissions, and best-in-class fuel efficiency.

MDX's new 5-speed, automatic transaxle has several features engineered specifically for use in a mid-sized luxury SUV, including: extra-wide gear ratios to optimize both start-up acceleration and highway cruising comfort, a lock-up torque converter and a rigid alloy case design.

The MDX's innovative VTM-4(TM)(Variable Torque Management(TM) 4-Wheel Drive) all-wheel drive system provides extra traction during acceleration and slippery road conditions. Additional benefits are improved dry-road vehicle dynamics, medium-duty off-road capability, and a lock feature to aid extraction from severe "stuck" conditions. A compact transfer case is bolted directly to MDX's front-mounted transaxle. A two-piece propeller shaft delivers torque from the transfer case to a rear axle drive unit. Two computer-controlled, electromagnetically-powered clutches engage as needed to provide torque to the rear wheels.



3.5-liter 60-degree V-6 with belt-driven single-overhead camshafts and four valves per cylinder
240 horsepower at 5300 rpm; 245 lb-ft of torque from 3000 to 5000 rpm
Remarkably broad and flat torque curve with 95-percent of peak output available from 2000 to 5500 rpm
Variable Valve Timing and Lift Electronic Control (VTEC)
Computer-controlled Programmed Fuel Injection (PGM-FI)
Dual-stage induction system
Direct Ignition system
100,000-mile tune-up intervals
Meets ULEV emissions standards in all 50 U.S. states
5-speed Automatic Transmission

Wide-ratio design provides a first gear with extra pulling power to start heavy loads in combination with a high top gear for quiet highway cruising
Components are engineered to provide the durability needed for on-road, off-road and towing use
Variable Torque Management 4-Wheel Drive (VTM-4)
Innovative, computer-controlled system unique to Acura MDX
Uses integral, single-speed transfer case, two-piece propeller shaft, and electromagnetically-actuated clutches in a rear axle drive unit to provide the best of all-wheel drive and part time 4-wheel drive
Optimum vehicle dynamics during both dry and slippery conditions
Extra traction and stability on snow and wet roads
Rear-driving traction for off-road use
Lock feature for getting unstuck in slippery conditions
212 lb. system weight is significantly lower than competitor systems
Fuel Economy and Exhaust Emissions

EPA fuel economy ratings of 17 mpg in city driving and 23 mpg on the highway (best combined ratings in class)
All MDX models are certified as light-duty-truck Ultra Low Emission Vehicles (ULEV) in all 50 states
The Acura MDX's engine is an advanced 3.5-liter, SOHC, 24-valve, 60-degree, V-6, aluminum-block-and-head design that is compact, light and powerful. A long list of technologies have been engineered to provide 240 horsepower, a broad and flat torque curve, very low emissions, high fuel efficiency, and exhilarating throttle response. The VTEC valvetrain and dual-stage intake manifold optimize cylinder filling efficiency across the engine's entire operating range. Low-restriction intake and exhaust systems, a 10.0:1 compression ratio, and roller-type rocker arms also aid efficiency.

The MDX 3.5-liter engine's block is die-cast and heat-treated aluminum to minimize weight. A deep-skirt configuration rigidly supports the crankshaft, minimizing noise and vibration. Thin-wall, centrifugally-cast iron liners help reduce overall length and weight. Each liner's rough as-cast exterior surface bonds securely to surrounding aluminum during the manufacturing process to increase strength and enhance heat transfer.

A forged-steel crankshaft is used for maximum strength, rigidity, and durability with minimum weight. Instead of bulkier, heavier nuts and bolts, connecting rod caps are secured in place with smaller, high-tensile-strength fasteners that screw directly into the connecting rod. Short-skirt, cast-aluminum, flat-top pistons are notched for valve clearance and fitted with full-floating piston pins.

Unlike many SUVs, the Acura MDX has four-valve combustion chambers, the best approach to optimum performance with excellent fuel efficiency and very low emissions.

Valves are clustered near the center of the bore to minimize combustion chamber volume and to provide ample squish area. A 10.0:1 compression ratio helps maximize thermal efficiency, power output, and fuel mileage. One centrally located camshaft per bank is driven by a fiberglass-reinforced toothed belt. Head gaskets are made of high-strength materials to contain combustion pressures.

6,809 Posts
Discussion Starter #16
Powertrain II

Acura's innovative Variable Valve Timing and Lift Electronic Control (VTEC) is one key to maximizing engine output across the full operating range. Ordinary engines have fixed valvetrain parameters - the same timing of valve lift and overlap whether the tachometer needle is struggling to climb out of the low-rpm range or screaming at the redline. The VTEC approach instead has two distinct modes so that operation of the intake valves changes to optimize both volumetric efficiency (breathing) and combustion of the fuel-air mixture. Less air is needed in the lower portion of the engine's operating range so rocker arms are programmed to follow cam lobes that provide low lift and reduced duration (shorter time open with less valve lift). The two low-speed intake cam lobes for each cylinder are purposely different to provide asymmetric air/fuel mixture flow into the cylinder. This yields a swirl effect, a miniature whirlwind about a vertical axis that is highly beneficial to clean and complete combustion.

At 4100 rpm, the MDX's powertrain control module commands the VTEC system to switch intake valve operation to the high-speed mode. In response, an electric spool valve opens to route pressurized oil to small pistons within the intake-valve rocker arms. These pistons then slide to lock the three rocker arms provided for each cylinder together. As a result, both intake valves follow a central high-lift, longer-duration cam lobe. The switching process takes just 0.1 second and is undetectable by the driver.

The extra lift and longer duration provide the added air and fuel the engine needs to produce high peak horsepower and a broader torque band. Instead of a peaky engine, the MDX has a powerplant that provides excellent performance at any engine speed.

The induction system atop the MDX's V-6 engine works in concert with the VTEC valvetrain to significantly boost torque across the engine's full operating range. Internal passages and two butterfly valves commanded by the powertrain control module are configured to provide two distinct modes of operation. The valves are closed at lower rpms. In this mode, the three cylinders on each bank draw air from only the nearer half of the manifold's internal chamber, or plenum. The volume of the plenum and the length of inlet passages are both tuned to maximize the resonance effect, wherein pressure waves are amplified within each half of the intake manifold at certain rpm ranges. The amplified pressure waves significantly increase cylinder filling and the torque produced by the engine throughout the lower part of its rpm band. Funnel-shaped intake trumpets - similar to those used on racing engines - are fitted to the uppermost end of each intake runner to improve air flow.

As the benefits of the resonance effect dwindle with rising rpm, the butterfly valves open to interconnect the two halves of the plenum, thereby doubling its volume. An electric motor commanded by the powertrain control module opens and closes the connecting butterfly valves via a cable. Now each cylinder draws intake air from the full plenum chamber. The inertia of the mass of air rushing down each intake passage helps draw in more charge than each cylinder would normally ingest. This phenomenon is the same effect produced by a low-pressure supercharger. The inertia effect greatly enhances cylinder filling efficiency and the torque produced by the engine at higher rpm. Concurrently, the VTEC system has switched from low-speed to high-speed valve timing to further enhance air flow through the intake valves and into each cylinder.

The net effect of the MDX's dual-stage intake manifold and VTEC valve train is that MDX delivers more torque and power than many of the large V-6s and small V-8s used by the competition, while also providing class-leading fuel efficiency and very low emissions. More than 95-percent of peak torque is available from 2000 to 5500 rpm. The corresponding band in the Mercedes-Benz ML320's 3.2-liter V-6 is only two-thirds as wide.

Fuel is delivered in sequence and timed to each cylinder's induction stroke by six injectors mounted on the lower portion of the intake manifold and aimed at each cylinder's central axis. A 16-bit, 32MHz central processor unit (CPU) within the MDX's powertrain control module calculates injection timing and duration after assessing an array of sensor signals: crankshaft and camshaft position, throttle position, coolant temperature, intake manifold pressure and temperature, atmospheric pressure, and exhaust-gas oxygen content. The CPU controlling the MDX's Programmed Fuel Injection (PFM-FI), VTEC valve train, and dual-stage intake manifold also communicates with CPUs that regulate the five-speed automatic transmission and the Variable Torque Management 4-wheel-drive system.

A low-restriction, high-flow exhaust system is crucial to efficient power and torque production. Collector pipes upstream of the catalytic converter are a thin-gauge, double-wall design using two concentric pipes separated by an insulating air gap. The catalytic converter is positioned only a short distance from the engine. This arrangement reduces the mass of exhaust system materials, thereby reducing the time needed to heat the catalyst after a cold start. The fast warm-up means that the catalyst begins cleansing the exhaust stream of emissions as soon possible. The catalyst, two muffling elements, and piping are all sized for high flow and low restriction. High-chromium stainless steel is used throughout the exhaust system for excellent durability. The twin exhaust outlets are polished for an attractive appearance.

Maintaining the correct ignition timing throughout all operating conditions is essential to producing maximum power with minimal emissions and fuel consumption. A powertrain control module (PCM) examines various engine functions as well as a block-mounted acoustic knock sensor to determine optimum ignition timing. In the event the engine is supplied with fuel lower in octane than the specified unleaded premium, the PCM retards ignition timing as needed to forestall detonation. As a result, the engine constantly operates at the point of peak efficiency. Spark is supplied to platinum-tipped, long-life spark plugs by six coil units positioned directly over the plugs in the cylinder-head access bores.

6,809 Posts
Discussion Starter #17
Powertrain 3

2002 Acura MDX -- Powertrain - Part 2

Before 105,000 miles of driving, the only maintenance necessary is routine inspections and fluid and filter changes. At 105,000 miles, it's time to adjust the valves and replace the platinum-tipped spark plugs.

An electronic control unit automatically adjusts the throttle and requests transmission downshifts as needed to maintain a constant speed in the cruise-control mode. Three buttons used to engage and adjust the MDX's cruise control are conveniently mounted on the right side of the steering wheel. Speed can be varied in one-mph increments and the system can be disengaged without touching the pedals.

An advanced 5-speed automatic transaxle was developed specifically for MDX to meet ambitious performance, and efficiency goals. A lock-up torque converter is provided to maximize fuel efficiency. Torque-converter lock-up and shift timing are both managed by a 16-bit, 20-MHz transaxle CPU that maintains a communications link with the engine's CPU. Gear and clutch materials and the transaxle case itself are all engineered to support towing, off-road driving, and 4-wheel-drive use.

A notable feature of this unit's design is extra-wide gear ratios. The difference in torque multiplication between first and fifth gears is nearly 5:1 (4.932) to balance low-speed pulling capability against fuel economy and the ability to cruise quietly on the highway.

Creative use of a clutched idler gear permits the transaxle to provide five forward speeds with little more weight or bulk than a typical four-speed automatic. An over-running clutch is provided for first gear to smooth upshift quality. An extra-capacity transmission fluid cooler is offered with the MDX's optional tow package to maintain acceptable lubricant temperatures during heavy-load conditions.

A direct-control strategy is used to provide real-time pressure management of the transmission's clutches. Various safety and control strategies are in place to coordinate engine and transmission operation. For example, driveline shocks during up- or downshifts are minimized by momentarily reducing engine torque during the shift. In neutral and park, engine rpm is automatically limited to 5000 rpm.

For driving through hilly terrain, a Grade Logic Control system monitors throttle position and vehicle speed and acceleration to avoid hunting and excessive shifting. A lower gear is held for a longer-than-normal period to provide better climbing ability on hills and more engine braking on downhill grades.

After studying various all-wheel- and four-wheel-drive systems offered by the wide variety of SUVs on the market today, MDX engineers concluded that virtually every one had functional shortcomings and was undesirably bulky and heavy. The direct result of that research was the creation of an innovative system that automatically and proactively distributes torque to all four wheels as needed. Called Variable Torque Management 4-wheel-drive (VTM-4(TM)), this new system provides front-wheel drive for dry-pavement cruising conditions and engages all-wheel drive only when there's a need to do so to improve mobility, stability, or maneuverability. Unlike many competitive systems that use an engagement strategy triggered by wheel slippage, the MDX's VTM-4 system anticipates the need for all-wheel drive and engages the rear wheels before slippage begins. Another special feature is a lock button, which temporarily holds engagement of the rear wheels to aid extraction from a slippery ditch or a snow bank.

To avoid the weight and bulk of a conventional transfer case, VTM-4's torque transfer unit is a compact cast-aluminum housing bolted directly to MDX's transaxle. Since this vehicle is engineered for medium-duty off-road capability, the transfer case is a single-speed permanently-engaged device without a low-range. Attached to the front wheel differential's ring gear is a helical gear that provides input torque to the transfer unit. A short horizontal shaft and a hypoid gear set within the case turn the drive ninety degrees, move it to the vehicle center line, and lower its axis by approximately 3.75-inches.

The two-piece propeller shaft that carries drive torque from the transfer case to the rear-drive unit is made of high-strength steel tubing to permit a smaller diameter. Minimizing driveline dimensions improves both ground clearance and interior room. The cross yokes attached at each end by friction welding are forged steel for high strength and low weight. The center support bearing is rubber isolated to block the transmission of driveline noise from the interior of the vehicle. A low-friction plunger joint located near the center of the propeller shaft accommodates relative motion between front- and rear-mounted driveline components. A tuned-mass damper inside the front portion of the propeller shaft cancels any bending tendency in response to powertrain vibrations.

Equal-length, front-wheel half-shafts have a plunger joint at their inboard end and a ball-type universal joint at the wheel end. Rear half-shafts are similar in design but use a double-offset joint at the inboard end and a ball joint at the outboard end. All universal joints are constant-velocity type.

6,809 Posts
Discussion Starter #18
Powertrain 4

A conventional differential is not used in the MDX's rear final-drive unit. Instead, a hypoid ring-and-pinion gear set supported by a cast-aluminum housing switches torque from the propeller shaft's longitudinal orientation to the lateral orientation necessary to drive the rear wheels. Surface grinding the ring and pinion gear teeth yields the quiet operation expected of a luxury SUV wearing an Acura nameplate.

A connection from the ring gear to each wheel's half-shaft is made by left- and right-side clutches. Each drive clutch consists of three elements: an electromagnetic coil, a ball-cam device, and a set of 19 wet clutch plates which are similar in design to clutches used in an automatic transmission. Ten of the plates are splined (mechanically connected) to the ring gear while nine of the plates are splined to a half shaft. Left and right clutches are identical.

When the VTM-4 system's electronic control unit (ECU) determines that torque should be distributed to the rear wheels, an electric current is sent to the two electromagnetic coils. The resulting magnetic field moves a rotating steel plate toward each fixed coil. Friction between that steel plate and an adjoining cam plate causes the cam plate to begin turning. As it does, three balls per clutch roll up curved ramps, creating an axial thrust against a clutch-engagement plate. This thrust force compresses the wet clutch plates, thereby engaging drive to the corresponding rear wheel.

Unlike mechanically actuated four-wheel drive systems, the VTM-4 system is infinitely variable. The amount of torque provided to the rear wheels is directly proportional to the electric current sent from the ECU and can be adjusted from zero to a preset maximum. This current constantly changes to deliver the optimum rear torque calculated by the ECU. An internal gear pump circulates VTM-4 fluid to cool and lubricate the clutches, bearings, and gears within the rear drive unit. Use of high-strength, low-weight materials - such as die-cast aluminum for the housing - minimizes the bulk and weight of this hardware. In fact, the weight of the entire all-wheel-drive system is about 212-pounds, only two-thirds the weight of comparable equipment carried by the Mercedes-Benz ML320.

There are three distinct modes of VTM-4 engagement. The first - called the acceleration torque control (ATC) mode - is unique to this system. It works even on dry pavement to distribute driving torque to all four wheels as the MDX accelerates from a stop to cruising speed. One notable benefit is that traction is immediately available to move the vehicle from rest through a slippery intersection before slippage occurs. (Once a wheel slips, the traction available for forward propulsion and lateral restraint is significantly diminished.) A second advantage is that apportioning drive torque among all four wheels greatly diminishes the likelihood of torque steer. Handling dynamics are also improved. Reducing the propulsive force carried by the front tires leaves more adhesion for steering the vehicle into a tight bend or for holding cornering arc in the middle of a turn. In other words, the MDX's dynamic balance is greatly enhanced by ATC logic.

Rear wheel torque rises smoothly from zero to the maximum setting in proportion to vehicle acceleration (both forward and reverse). At higher speeds, the front wheels are capable of providing the desired thrust with excellent handling so torque delivered to the rear wheels automatically diminishes with speed. During constant-speed driving, all driving torque is delivered by the front wheels in the interests of smoothness, quietness, and fuel efficiency.

The second engagement mode uses wheel slippage control logic. If the difference in rotational speed between front and rear wheels rises because of a slippery surface or poor traction at the front of the vehicle, that condition is detected by wheel-speed sensors which are monitored by VTM-4's ECU. In response, the ECU commands an increasing amount of torque for the rear wheels. Torque is proportional to both slip rate and the rate at which the slip rate is increasing. This operation is similar to conventional slip-based all-wheel-drive systems already on the market.

The third mode of all-wheel-drive engagement is activated when the driver taps a lock button mounted on the instrument panel. The maximum amount of rear-drive torque is locked in until the vehicle gets moving and exceeds six mph, at which time rear drive torque is gradually diminished. By 18 mph, the lock mode is fully disengaged. When vehicle speed drops below 18 mph, the lock mode automatically engages. The shift lever must be in the first, second, or reverse-gear position to use the lock mode.

The maximum torque delivered to the rear wheels is sufficient to climb the steepest grade observed on any public road in America - 31 degrees (60-percent slope) - with a two-passenger load on board. The MDX will also move from rest up a 28-degree (53-percent slope) dirt grade. On a split-friction grade (different amounts of traction at each wheel), VTM-4 automatically provides sufficient rear-wheel torque to help the vehicle climb a steep, slippery driveway to enter a garage.

6,809 Posts
Discussion Starter #19

2002 Acura MDX -- Interior - Part 1

In the MDX, clean, solid forms on the instrument panel and door areas define a wide open and luxurious space. Positioned within that space are the driver's cockpit and a multi-use console that is reminiscent of other Acura models. Grained panels and leather trim throughout the interior complement the design.

The focal point of the instrument panel is the personal computer aspect of the center control panel for climate control, music system, trip computer and the available navigation system. The console storage compartment offers a wealth of functional features without diminishing the overall sense of roominess.

Control switches, beverage holders, storage pockets, power outlets, and audio speakers are located throughout the interior to offer a remarkable degree of ergonomic functionality while upholding the desired clean, purposeful theme. Seats are designed with a luxurious, stylish appearance and a sporty image consistent with this product's athletic driving attributes.

Front and side airbags for the driver and front seat passenger are standard, as are a headrest and 3-point safety belts for all seven passenger seating positions. In the interest of versatility, second- and third-row seats were designed for easy configuration from seven-passenger vehicle to cargo vehicle with a flat cargo floor - or any layout between the two extremes. And to make the most use of the interior volume, an under-floor storage compartment is also provided behind the third row of seats.

The Acura MDX's interior provides more useable seating and cargo space than any of its key luxury SUV competitors - without resulting in a bulky exterior. This was achieved by taking advantage of its extra-wide wheel-track dimensions and an innovative driveline that delivers exemplary power, performance, and all-wheel-drive traction without intruding on interior space. MDX's interior has a low, flat floor for the first- and second-row seating positions for easy entry and egress. The lack of a large and intrusive driveshaft tunnel and unwieldy rear-axle intrusion yields room for up to seven passengers in three seating rows, a highly versatile center console and a cargo area wide enough to accept four-foot-wide sheets of building materials.

In keeping with Acura's tradition of selling fully-featured products, MDX offers a wealth of power accessories, conveniences, and refinements as standard equipment. The MDX is the world's first SUV with a synchronized front and rear climate control system engineered for rapid warm-up in cold weather, expedient cool-down during summer months, and maximum all-around comfort for all seven passengers.

The center console is designed to provide a front-seat armrest, a handy storage compartment, and second-row-passenger's serving tray. A large central LCD display screen houses the standard multi-function trip computer and the available DVD-based satellite-linked Acura Navigation System. Climate-control buttons and displays are alsointegrated within the display screen for easy access, viewing and operation. Both the standard and enhanced Acura/Bose(R) music systems play AM/FM/CD, and cassette source material. The premium Bose(R) system adds an in-dash, six-CD changer and an additional 8-inch speaker.

MDX's steering wheel uses a thick rim section for a sporty, substantial feel. The leather cover is perforated in grip areas to prevent slippage. Cruise control switches are positioned between the right-side spokes while the music system control switches are in a corresponding position on the left.

The transmission shift lever is also covered in matching perforated leather. It moves through a gate that helps the driver quickly find the desired gear position. The center panels of the leather seating surfaces are also perforated to provide additional ventilation.

Three-row seating - two bucket seats in front, a three-passenger, 60-40-split middle-row bench seat, and a two-passenger 50-50-split bench seat in back - is standard. Leather-trim on seating surfaces for the front two rows is also standard. Third-row seats are upholstered in a leather-like, matching vinyl material for resistance to spills, dirt and scuffing.

The driver's seat features eight-way power adjustment and a special adjustable lumbar support that flexes to match the natural curve of the spine under the weight of a passenger. Both the upper torso and the pelvis are held in an orthopedically correct position. The lower cushion design provides excellent comfort, even for larger occupants. Side bolsters are configured to comfortably hold the driver during spirited driving without impeding ingress and egress. The relatively flat, open design of both front seats give the driver and front passenger the freedom to adjust seating positions easily for added comfort on long trips. Integrated headrests and electric heating elements are standard in both front seats. In MDX models with the Touring Package, memory seating positions - as well as the rear-view mirror pre-sets - are matched to either one of the two keyless remote entry fobs, and automatically adjust to each driver's pre-selected positions.

All seating positions have three-point seat belts. Front seat belts are equipped with pretensioners and automatic load limiters that are activated during severe frontal collisions. The MDX comes with standard driver's and passenger's front airbags. The dual-stage passenger's front airbag can deploy at the most appropriate of two rates - depending on the severity of the crash. In addition, if the driver's or passenger's seat belt is not fastened, the airbag deploys at a lower collision speed to help offer more protection to the unbelted occupant.

The driver's and front passenger's seats also feature side airbags mounted in the seat bolster closest to the door. The passenger's seat is equipped with a system designed to disable side airbag deployment and help prevent injury to a small child (or small-statured adult) if they lean into the side airbag deployment path. Once the child returns to an upright seating position, the side airbag will reactivate so it can deploy and help protect the child in a side impact.

MDX's middle-row seat is a 60-40-split design with comfortable room for three passengers, height-adjustable headrests, and a fold-down combination armrest and dual cupholder. To comfortably accommodate taller passengers, MDX engineers located seat height a reasonable distance above the flat floor and made the door openings larger for unrestricted entry.

Second-row seatbacks can be adjusted through seven positions of recline. Three separate tether anchors are provided at the rear of the backrests for securing tether-style child safety seats. For 2002, the Lower Anchors and Tethers for Children (LATCH) system has been added to the second row of seats. The LATCH system features ready-to-use tethers imbedded in the rear seats and allows compatible child safety seats to be installed without using the vehicle's seat belt system for added safety.

To fold the second row seat, a special four-bar linkage automatically cantilevers the bottom seat cushion both down and forward as the seat back is folded down to create a flat load floor. In contrast to some competitor's SUVs, releasing, lowering, raising, and re-latching the folding second-row seat are simple one-handed operations. Placing a child in the second row seating area or loading a grocery bag into the cargo area through the back door are, thanks to design ingenuity, simple tasks.

A convenient walk-in feature is provided at the right (curb) side of MDX's second-row seat. Lifting one lever permits the whole seat to slide forward on its tracks and the backrest to tilt forward, providing an entry path to the third row seats. Simply pushing the seat rearward again re-latches the seat in its rearmost position. The seat-tilt mechanism, step-in height, and the opening provided between the open second-row seat and the door frame are all sized for easy and convenient use by children. A hand-hold is also provided on MDX's rear side wall trim to simplify passenger access to the third row seats.

6,809 Posts
Discussion Starter #20
Interior #2

MDX's third row is an occasional seat configured specifically for children or small adults. A slightly elevated hip point height provides good forward visibility for third-row passengers while headrests are both height adjustable and removable. Like the second row, backrests can be reclined through six positions. Two tether anchors are provided for securing one or two tether-style child safety seats in the third row seats.

When not in use, either half of the third-row seat can be folded flat on a 4-bar linkage (similar to the second row seat) that brings it flush with the floor. Handles positioned at the top-outboard corners are accessible both from the rear doors and from the tailgate. This lift handle also releases each half of the seat so it can be raised or lowered independently. The third-row seat headrests can be stored in the cargo compartment located under the rear floor.

Engineers configured MDX to handle an amazing range of contemporary family storage needs. In addition to the center console bin and beverage container holders, MDX has a long list of built-in features and the easy adjustment necessary to serve drivers of premium SUVs.

The hinged glovebox's capacity is twice as large as the Lexus RX300's box. It is also illuminated, lined with flocking material, and lockable. A motion damper allows a controlled, fluid opening motion - preventing the lid from banging open against a front passenger's knees.

The front door pockets are purposely configured to hold maps, guide books, and road atlases while the rear door pockets are just right for sunglasses, small toys, treats, and bottled beverage containers. Armrests for the third-row seating area have small storage boxes covered by latchable lids. A rear under-floor compartment is ideally located for easy access through the open liftgate. Pockets stretched across the rear of the front bucket seats are ideal for storing a variety of things for easy access by front-row and second-row passengers.

MDX's impressive cargo volume - the single attribute that attracts most buyers to SUVs in the first place - is, as you would expect, versatile and practical. Four-foot wide sheets of building materials slide in between wheel wells with ease - an attribute not matched by MDX's direct competitors. With second- and third-row seats folded down, MDX offers 82 cubic feet of cargo space to swallow virtually whatever you may need to carry. No other competitor in MDX's class can match this surprising capacity. Only full-size, truck-based models (such as the Ford Expedition and Chevrolet Tahoe) have greater cargo storage capacity.

A low load floor and seats that fold flat are the keys to versatility. To simplify conversion of the seats to a cargo area the third-row and second-row center seat belts easily detach from their floor anchors with a patented and simple-to-use mechanism. Six cargo tie downs are located strategically around the perimeter of the load floor to help secure objects susceptible to sliding or rolling. And since both the second- and third-row seats are split designs, six cargo/seating configurations are possible to suit carrying needs. Various accessory hardware is available from Acura dealers to safely and conveniently carry bicycles and other gear inside the vehicle and the roof rack (standard on MDX with Touring Package, optional on MDX) is useful for hauling skis, surfboards, or bulky camping equipment.

Thanks to the wide-opening liftgate and flat floor, large items, such as the box for a 32-inch TV will slide right into place for convenient transport. And it's possible to tote home 15, 3-cubic-foot bags of garden mulch without blocking outward vision. When the middle seating row is in use, there's still 22-cubic feet of space available, more than a full size car's trunk. And if it's necessary to use all three rows of seats, MDX still provides 7.6-cubic feet of space behind the third-row seat - enough for eight paper grocery bags, four duffels and a cooler, or a full set of golf clubs.

A separation net is offered as a dealer-installed accessory that attaches to four built-in attachment points, two in the floor and two in the ceiling, and provides a separate area for cargo behind the second row of seats, along with a cargo liner and liftgate apron that can be folded out over the rear bumper when the liftgate is opened.
1 - 20 of 27 Posts