The Acura ZDX: A Vehicle Apart

Gary S. Vasilash

This time the folks at Acura got the entire assignment: the ZDX was designed in California, engineered in Ohio, and is being built in Ontario. And this is no simple vehicle, not by a long shot.

Although marketing people at car companies often talk about "white-space" products while referring to what is obvious to anyone else just another entry into an existing category, the Acura ZDX is actually a vehicle that may be the first (or second, if the BMW X6 is taken into account) in its space. The nomenclature as to just what the ZDX is--a sedan on steroids, a station wagon, a 22nd century SUV--isn't entirely clear, but what is clear is that when Gary Evert, vehicle chief engineer, talks about it, he doesn't use the word "crossover." Perhaps this has something to do with the fact that the ZDX borrows elements from the Acura MDX, which is unabashedly an SUV, not a crossover. Yet visually, the ZDX is anything but a traditional SUV.

Two more things on the vehicle type. Evert was the large project leader (a.k.a., chief engineer) on the Acura RDX, which is arguably a crossover. So he's done one. He knows what it is. And many of his colleagues on the engineering team for the ZDX (e.g., Jason Widmer, Todd Hemmert, Jeremy Nutting) had worked on the current-gen MDX.

The exterior was designed by Michelle Christensen, Acura's first female designer. Christensen, who was hired by Acura right out of Art Center, recalls spending time with her dad in the family garage, where he would work on hot rods. She wanted to give her first exterior design something of the flair of the cars she grew up with, and consequently there are not only curves, but the deeply sculpted rear shoulders that are somewhat characteristic of vintage hot rods&mash;although in Christensen's design, these shoulders are far more sinuous than the rear fenders that typically covered the hot rod's racing slicks.

And if there is a lesson to be learned from the development of the ZDX, it is that the designs created by people like Christensen can't be realized without the help of a whole lot of engineers and manufacturing specialists, as is particularly the case with those rear shoulders. That rear quarter side panel&mash;a single piece&mash;features what is by far the deepest draw that has been stamped by Honda, a 320-mm panel depth. To develop this piece, a year-and-a-half was spent trying to figure out how to execute it. There was a two-piece solution proposed&mash;putting the seams in the taillight area and under the rear door cutline&mash;but only after they'd considered everything from hand-fabrication to hydroforming. That two-piece idea was rejected. Another factor that they had to accommodate is the 8-mm radius on the character line that stretches along the side of the vehicle, from near the top of the front wheel opening all the way back to taillamp. Finally, they developed a stamping method that is facilitated by the use of a low-friction phosphate coating between the die and the steel panel.

And you read that right: They worked it for a year-and-a-half.

Another feature of the ZDX is a panoramic roof that includes what is said to be the longest glass roof in the industry, stretching from the leading edge of the windshield to the trailing edge of the tailgate glass. This "hood-to-bumper" glass measures some 3.75 m. (It features a sliding glass panel measuring 48.2-in. wide by 24.5-in. long.) While providing a sense of spaciousness within the cabin, it also brings with it an engineering challenge from the point of view of body rigidity. As this opening is not only long but the full width of the roof, it makes the vehicle somewhat convertible-like as regards rigidity. What's more, there was a concern regarding rollovers. The engineers determined that the area surrounding the tailgate, the "tailgate ring," is critical to providing rigidity, not only for roof crush, but also for allowing a place for the rear suspension to be mounted for improved handling. Forty-eight percent of the body-in-white is produced with advanced high-strength steels, in areas including the A- and B-pillars, floor sills, roof frame, cross braces, and floor cross members. (Five percent of the ZDX body components are made with aluminum, such as the hood, which is calculated to be 15 lb. lighter than it would be if produced with steel. Another major aluminum component is the instrument panel support assembly, which bridges between the A-pillars and the front floor cross member. This support is a structural member that is fabricated from extrusions and stamped aluminum sheet. It is calculated to save 14 lb. compared to steel.)

What's evident is that there is plenty of glass on the ZDX. Because there is a concern with wind noise, a special acoustic glass is used for the windshield. It has a sandwich-like construction, with a layer of transparent and elastic acoustic membrane sandwiched between two sheets of 2-mm safety glass. The total thickness of the windshield is 4.7 mm. The roof panel (which is tinted to block 80% of all light and 90% of the UV radiation) is 4 mm thick. The front side glass is 5-mm thick, the rear side glass is 3.5-mm thick, and the tailgate glass is 3.1-mm thick.

Like all new vehicles engineered by Honda, the ZDX features the Advanced Compatibility Engineering (ACE) body structure, the point of which is, in the case of a frontal collision, to distribute collision forces throughout the structure so as to maintain the integrity of the passenger cabin. As the ZDX is a somewhat larger vehicle than a midsize sedan, it has a frame member below its front structure to engage the front bumper of smaller vehicles in the case of a head-on collision. Keeping the consequences of collisions as minor as practical is the rationale for an interesting option available for the ZDX is the CMBS system&mash;that's Collision Mitigating Braking System. It is based on a millimeter-wave radar unit that's inside the front grille that monitors the distance between it and a vehicle directly ahead of the ZDX. The range is up to 300 ft. The distance is tracked and if the closing rate between the ZDX and the other vehicle indicates that there is the likelihood of a collision, there are a buzzer and a display warning. If the driver of the ZDX doesn't slow the closing rate, then the buzzer and warning light is supplemented by a light seatbelt retraction and light braking. If it is calculated that a collision is unavoidable, then the seatbelt retraction and the braking force both ratchet from light to strong.

While the CMBS is the sort of thing that you don't want to do, the ZDX does have the sort of performance powertrain that provides the potential. It features a 3.7-liter DOHC, all-aluminum V6 with variable-valve timing and lift control that puts out 300 hp @ 6,300 rpm and 270 lb-ft of torque @ 4,500 rpm. It is mated to Acura's first six-speed automatic transmission that offers paddle shifters for driver control of the gear selection, including double kickdown capability. And the vehicle is fitted with the Super-Handling All-Wheel-Drive (SH-AWD) system that can distribute the torque front to rear and left to right.

While the ZDX is nominally a five-passenger vehicle, the vehicle was designed primarily for couples. As Jason Widmer, ZDX principle engineer, says an interior theme is "2 + Freedom," which he explains means two people and their belongings. In fact, the front seats are described as the "Primary passenger zone." There is a back seat and cargo space behind it (26.3-ft3), if the second row is folded flat, there's plenty of room (55.8-ft3). What's more, they've engineered the rear side panels in the cargo area so that they can be removed, thereby permitting placing golf bags back there. And there is a 2.2-ft3 storage well under the floor.

What ever the ZDX is, it is certainly different.


That’s What “Friends” Are For

Being a responsible contemporary corporate citizen, American Honda, in the lead-up to the introduction of the Accord Crosstour, posted some prelimi-nary photography on Facebook.

Cue the flamethrowers.

Putting the best face on the digital brouhaha, John Mendel, executive vp of American Honda, says that they were encouraged to discover “the highly passionate fan base that Honda has.” He goes on to say that henceforth, as they continue with these social media methods, they’ll post “better, more accurate pictures than what we happen to have at the time.”


Honda’s Crosstour: Not a ZDX, But. . .

The first thing that needs to be gotten out of the way is that the Accord Crosstour is not Honda’s version of the Acura ZDX.

Note well the name of the vehicle: the Accord Crosstour. The Accord, of course, is a car. The MDX, upon which the ZDX is based, is an SUV. So the platform for the Crosstour is entirely different than its upscale brethren. And it is being built at the East Liberty, Ohio, plant, the highest ranked 2009 J.D. Power Assembly Plant Quality Award facility in North America, and where the Civic, CR-V, and Element are produced.

Categorically, the Crosstour is a crossover vehicle. From the styling point of view it is more like a car than a SUV, and while there are some differences from the Accord sedan, such as bolder front grille and textured plastic trim to provide a more robust appearance. Still, the vehicle, particularly in a front quarter view, doesn’t look like a five-door, largely because the roofline sweeps back to the rear of the car as the beltline angles upward. While describing this as “coupe-like” would be an exaggeration, it is decidedly different from the more rectangular executions of this body style from other manufacturers.

Dimensionally, it is quite close to the Accord sedan, with one major exception, as you will see:





Length:196.8 in.194.3 in.
Wheelbase:110.1 in.110.2 in.
Width:74.7 in.72.7 in.
Height:65.7 in.58.1 in.
Passenger volume:101.4 - ft3 (2wd)101.0 - ft3 (EX trim)
Cargo volume:51.3 - ft34.0 - ft3

The cargo volume figure for the Crosstour is predicated on the second row of seats being folded down, which is something that is readily accomplished through the simple use of levers that are mounted near the interior fender wells. The ground clearance is comparatively low at 6 in. (cf., Nissan Murano at 7.4 in. and Toyota Venza at 8.1 in.)

The Crosstour is powered by a 271-hp, 3.5-liter V6 that features a diecast aluminum alloy block with cast-in-place iron cylinder liners that are produced with a centrifugal spin casting process so that they exhibit high strength and have low porosity. The heads are aluminum, as well; these low-pressure castings have integrated exhaust manifolds; the integration not only facilitates airflow, it also helps reduce parts count). The short-skirt pistons are aluminum. There’s a forged-steel crankshaft. One interesting assembly aspect of the powertrain is the use of fasteners that screw right into the connecting rod to hold the con rod caps in place rather than using nuts and bolts. The transmission is a five-speed. One feature that’s new in a Honda model is “Cornering G Shift Control.” This uses sensors to measure the difference between the right and left wheel speeds such that if it determines the vehicle is cornering, the transmission is prevented from upshifting until the vehicle is out of the turn.