2018 Subaru Crosstrek moves to new stiffer global platform

  • 10-Aug-2017 07:16 EDT
18My_Crosstrek_Prem-front.jpg

To create the 2018 Crosstrek, FHI engineers increased the wheelbase by 1.2-in. over the previous model. Overall length and width are also increased. Ground clearance is 8.7 in.  (Subaru image) 

Twenty years ago Fuji Heavy Industries engineers first leveraged the subcompact Subaru Impreza platform to create the popular Forester CUV. They again used Impreza to create the 2012 Crosstrek which soon became the brand’s third-best-selling model in the U.S., and number two in sales among B-segment CUVs. Now comes a much-improved, second-generation 2018 Crosstrek which company engineers claim is 95% new.

It’s underpinned by the substantially stiffer all-new Subaru Global Platform (SGP) which brings improved ride, handling and NVH attenuation, as Automotive Engineering found during the recent media launch. Crashworthiness is also improved, the company claims. Crosstrek is the second Subaru underpinned by the new SGP, following the 2017 Impreza. Eventually all new models—from the 2019 Ascent three-row CUV to new WRX, Forester, Legacy and Outback models—will be on it.

The 2018 Crosstrek rides on a 104.9-in. (2664-mm) wheelbase, an increase of 1.2-in. (30.4 mm) over the previous model. Overall length and width are increased 0.6-in. (15.2-mm) and 0.9- in. (23 mm), respectively. The 60/40 split flat-folding seat seats and widened liftgate opening provide improved cargo loading and greater utility. Ground clearance is 8.7 in. (221 mm); wheels are 17-in.

Besides the vehicle’s new exterior and interior, the vehicle is equipped with an upgraded (80% new), direct-injected 2.0L horizontally-opposed ‘boxer’ four-cylinder gasoline engine, Active Torque Vectoring driveline, traction-enhancing X-Mode for off-road use (standard with the continuously-variable transmission (CVT), a new multimedia system with Android Auto and Apple CarPlay capability and many new driver-assist technologies.

Alternative to axle decoupling

Our recent test drive through the scenic Black Hills of South Dakota, during the U.S. media launch, included many unpaved roads and some challenging off-road situations. After the drive we sat down with Project Senior Manager Shinichi Numata and car line manager Todd Hill. According to Numata, Impreza and Crosstrek share the same wheelbase and are of similar size, “but future models will come to this platform with different sizes, different wheelbases, widths and lengths,” he explained.

“The basic idea is that many parts -- nuts, bolts, fasteners, brackets, etc. -- are shared, so engineering resources can be shared for lower development needs and costs along with more differentiation between trim levels and models,” Hill added. With 12% more high-strength and 9% more hot-press steel than the previous platform, the SGP is claimed to be 70% stiffer torsionally and 90% (front lateral) to 100% (rear subframe) stiffer than the outgoing architecture. The platform is designed to accommodate multiple powertrains, including EVs and hybrids.

Numata confirmed that as learnings accumulate from one new vehicle to the next, the development process becomes somewhat easier, faster and more cost efficient. “This Subaru Global Platform is basically a process of how a platform should be built,” he says. “The major parts are not physically the same [from one model to another], but the concept on how they are designed is shared with all of our car lines, and how they go together is the same. The car lines’ sizes will be different, but their platforms are designed with the same idea. The development used for this Crosstrek can be used for larger vehicles as well.”

Can this latest AWD system disconnect an axle to reduce driveline losses? “No,” Hill stated. “Subaru Symmetrical All-Wheel Drive is always sending some level of torque to all four wheels. It varies based on conditions, but we never decouple.” Numata agrees that fuel efficiency could be improved by decoupling when AWD is not needed, “but the vehicle’s behavior would be different compared to coupled. So thinking on the safer side, Subaru decided for it to be coupled all the time.”

Still, the 2018 Crosstrek delivers best-in-class AWD EPA economy at 27 mpg city, 33 highway and 29 combined with the CVT and 23/29/25 with the standard 6-speed manual.

Also, Hill adds, “it's not an apples-to-apples comparison with the competition. Because the ‘boxer’ engine has a direct feed off the back of the engine, with the front axles coming right out of the transmission, we have less losses to begin with. The layout is more efficient vs. in-line engine competitors with a transfer case and other components. We are not routing power around a convoluted path.”

The wider-ratio-spread CVT, complete with seven driver-selectable ratios, is engineered and built in-house by FHI, but the chain and some other key components are jointly developed with suppliers. “Our drivetrain layout is unique, so we can't buy off-the-shelf transmissions,” Hill said. “We have to make our own.” And Numata confirmed that there are joint programs with Toyota beyond the BRZ/Toyota 86 sports cars, especially in electrification.

More power please

One important feature is available EyeSight Driver Assist Technology, sourced from Hitachi Automotive Systems. It uses twin stereo cameras mounted high on the inside of the windshield behind the mirror. “Dual cameras are quicker-reacting than a radar/single camera system,” Hill explained. “They detect distance more correctly, similarly to human eyes,” Numata added. “Another advantage is that they are not in the front bumper where someone can smash into them in a parking lot.”

EyeSight includes Adaptive Cruise Control, Automatic Pre-Collision Braking and Lane Departure and Sway Warning, and Blind Spot Detection with Lane Change Assist and Rear Cross Traffic Alert are available. Additional available driver-assist technologies include Reverse Automatic Braking, steering lines in the standard rear-vision camera and new Steering Responsive Headlights and High Beam Assist.

While Subaru cites the ($21,000-$27,000 three-trim-level) Crosstrek’s competitive set as the growing field of subcompact CUVs, it’s slightly larger than most in that class. And perhaps unique to the class, it's capable of towing up to 1500 lb/680 kg. The vehicle is surprisingly roomy, comfortable and quiet inside and demonstrated livelier levels of steering (with a 13:1 ratio), braking and handling than most CUVs.

But even with just two adults aboard (at altitudes up to 5000 ft/1524 m), its engine really needs more output than its rated 152 hp (113 kW) and 145 lb·ft (196 N·m). We recommend Subaru’s turbocharged 2.0L H-4 as an up-level option.

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