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7th-generation Golf GTI on sale in US; lighter and more fuel-efficient

30 May 2014

Volkswagen of America, Inc. announced the official arrival of the new 2015 Volkswagen Golf GTI in US. The MQB-based seventh-generation of the original “hot hatch” (first introduced in the US in 1983) preserves the performance and handling style of its forebears, while being bigger—but lighter—and more powerful—but more fuel efficient—than its immediate Mk 6 predecessor.

The new GTI is also Volkswagen’s introduction of the MQB (modular transverse matrix) vehicle platform to the North American market—a significant step in standardizing, simplifying, and improving the design and creation of products across the entire Volkswagen Group portfolio. The use of the MQB also more easily supports the deployment of alternative powertrain architectures, as seen in the plug-in hybrid Golf GTE. (Earlier post.)

Golf GTI Exterior 2

The MQB architecture allows for a more cab-backward design, which gives the new Golf GTI a more upscale appearance while retaining classic design cues from the Mk 1 and Mk 4 generation GTI models.

2.0L Gen3 EA888 engine. The all-new Golf GTI features a Gen 3 EA888 2.0-liter turbocharged and direct-injection TSI engine (earlier post) that makes 210 hp (157 kW) at 4,500 rpm and 258 lb-ft (350 N·m) of torque form 1,500 to 4,500 rpm, figures that are 10 hp and 51 lb-ft higher than in the previous-generation GTI model.

The available Performance Package modifies the engine programming to hold peak torque for an extra 200 rpm, enabling the EA888 to produce an extra 10 hp for a total of 220 hp (164 kW) at 4,700 rpm.

Golf GTI Engine
Under the hood of the new Golf GTI. Click to enlarge.

Despite this increase in horsepower and torque, the new Golf GTI is more fuel efficient than previously. When equipped with the six-speed manual transmission, the Golf GTI records an EPA estimated fuel economy rating of 25 mpg (9.4 l/100 km) in the city and 34 mpg (6.9 l/100 km) on the highway, compared to the previous-generation GTI’s ratings of 21 mpg (11.2 l/100 km) city and 31 mpg (7.6 l/100 km) highway.

When equipped with the optional six-speed DSG dual-clutch automatic transmission, the fuel economy improves from the previous model’s 24 mpg (9.8 l/100 km) city and 32 mpg (7.4 l/100 km) highway to EPA estimated fuel economy ratings of 25 mpg in the city and 33 mpg (7.1 l/100 km)) on the highway. The DSG transmission also incorporates a launch control feature.

Augmenting the EA888’s 16-valve, dual-overhead-camshaft layout is the latest variable cam phasing system, which controls both intake and exhaust valves, as well as a variable lift system for the valves themselves.

First drive and the GTx family.
Way back in the early 1990s—before the days of commercials with kinetic “un-pimpings” and miniature Darth Vaders—Volkswagen ran a brief ad campaign with the simple slogan “Fahrvergnügen” (driving enjoyment).
While that campaign was short-lived (and probably not that successful), the one-word emphasis on acceleration, control and handling is a good tag for our first seat time in the new GTI. The new Golf GTI is extremely balanced, fast with crisp handling, and very fun to drive. It’s also extremely comfortable, given Volkswagen’s emphasis on improving not only the driving power and performance, but also upping the internal content of the Mk 7.
As a side note, although Volkswagen is not lowering the sticker price of the GTI, on a content-adjusted basis—i.e., what you get for what you pay—the price of the GTI is down about $2,200. Volkswagen has loaded it up, contributing again to performance and comfort.
The GTI is currently the only member of the “Gran Turismo” family on sale in the US, although Volkswagen is currently selling the diesel GTD, earlier post, and the plug-in hybrid GTE, earlier post) elsewhere.
Having had a very short amount of driving time with each over the past months, we’d say that while all three have a common core of performance and handling attributes, there are some usability differences stemming from the different powertrain choices. (Again, a side-note. The simple availability of the three major powertrain choices on a major model (due to the MQB) from one of the top automakers is a good problem to have—assuming we get the GTD and GTE in the US.)
Grossly oversimplifying, and leaving out the environmental pluses and minuses due to fuel choices, we’ll note that the GTI is faster off the line and feels quicker to the sprint. (The US GTI does not offer start-stop, which the GTD model we drove did, and which, of course, the GTE features.)
Aside from the lower speed, start-stop operation, the diesel GTD is as satisfying and fun to drive as the gasoline GTI. And as a road car for long-distance, higher speed trips, the diesel platform excels.
Our time with the GTE was the shortest, but long enough to feel the GT family “DNA”. However, at this point, on initiating aggressive acceleration—when both the motor and the gasoline engine are brought to bear—there is a slight lag more akin to a combustion engine vehicle than an electric. (By contrast, mashing down the accelerator pedal in the all-battery e-Golf produces the archetypal "Wheee!" of instant electric acceleration. The difference between the two is more apparent when the two are driven back-to-back.)

The single-scroll turbocharger (commonly engineered by IHI and Volkswagen) feeds intercooled air through the aluminum-alloy crossflow cylinder head. Fuel is delivered by the latest high-pressure direct-fuel-injection system at 2,900 pounds per square inch, compared to 2,176 psi on the previous EA888 engine.

The new engine is designed to be both lighter than the old unit and also to reduce friction. Weight is reduced thanks to a combination of compact design, streamlined componentry, and a focus on lightweight materials. The cast-iron engine block uses a wall thickness of just 0.12 inches to reduce its weight to 72 pounds, while a lightweight polymer oilpan and aluminum-alloy screws and fasteners also trim mass.

Other changes reducing engine weight include a reduction from eight to four crankshaft counterweights. Internal friction is reduced due to measures such as roller bearings for the engine’s balancer shafts and a reduction in the size of the engine’s main bearings.

The engine is also extremely compact, illustrated by the way in which the exhaust headers have been integrated directly into the cylinder head. This not only improves the system coolant operation (aiding rapid warm-up, which helps improve efficiency), but it also allows greater thermal management of the exhaust stream.

This, along with a turbocharger that can withstand extremely high exhaust temperatures, means the forced-induction system doesn’t require complex fuel enrichments under high load, helping improve both efficiency and longevity.

Suspension and chassis. As the first US-market vehicle built on Volkswagen’s MQB modular platform, the new Golf GTI features an all-new body-in-white. The unitary construction chassis has two solid-mounted subframes with bolt-on front fenders, and utilizes new technologies such as the laser clamp welder, which produces “wobble seam” welds in a wave pattern to maximize strength in a limited space, offering up to four times the strength of a traditional spot weld.

The all-new Golf GTI’s stamped steel body and chassis now has 28% of its parts in high-strength, hot-formed steel, as opposed to 6% in the previous GTI. This technology—along with the use of newly developed ultra-high-strength steels that weren’t available during the last generation’s development and now comprise 9% of the new Golf GTI’s bodyshell—allow much of the chassis and body to be constructed from thinner and lighter parts without any loss in strength.

Using selective thickness for parts, a single component can be tailor-rolled to have as many as 11 zones of varying thicknesses. The result is a body-in-white that weighs 51 pounds (23 kg) less than the previous car’s despite offering 10% more torsional rigidity. Overall, the new Golf GTI is 53 to 82 pounds (24 to 37 kg) lighter than the previous-generation car, despite its larger size and additional equipment.

The new Golf GTI features a strut-type front suspension with lower control arms and a multilink rear suspension, both of which are controlled by coil springs with telescopic dampers.

The Golf GTI has a lowered sport suspension, which is 0.6 inches lower than the Golf TSI and TDI Clean Diesel models. The front suspension includes a 24-millimeter anti-roll bar while the rear has a 20-millimeter version, 2 mm larger at the front and 1 mm thicker at the back compared with a regular Golf TSI model.

The Golf GTI can also be ordered for the first time in the US with the latest version of Volkswagen’s DCC adaptive damping system, which manages the suspension’s rebound and compression rates individually, helping to improve vehicle dynamics. This feature is only available on SE and Autobahn models fitted with the optional Performance Package.

All 2015 Golf GTI models are equipped with the XDS+ Cross Differential System—an updated version of the XDS system seen on the previous GTI. This technology acts somewhat like an electronic substitute for a traditional mechanical limited-slip differential, working by actively monitoring data from each wheel sensor. If the suspension becomes unloaded, the system automatically applies braking to the driven inside wheel as needed to reduce understeer (the tendency for the front wheels to run wide). This not only helps keep the Golf on the road, but also improves handling and cornering performance.

Another new feature on the Golf GTI is the ESC Sport function for very experienced drivers. The system is activated by a two-stage switch on the center console. If the driver pushes the button once briefly, the ASR (traction control) function is deactivated. When the button is pressed longer than three seconds, Electronic Stability Control (ESC) switches to the ESC Sport mode. In high-speed driving, such as on a racetrack, the ESC system operates at a higher threshold for even more agile handling. ESC can also be activated through the CAR settings menu.

On Golf GTI models equipped with the Performance Package, a torque-sensing limited-slip differential dubbed VAQ is fitted. This electronically-controlled differential works in concert with the existing stability systems (including the related brake-based XDS+ electronic differential lock) and improves traction and performance. Tests at the Nürburgring Nordschleife track have shown lap-time improvements of more than eight seconds on cars equipped with the new differential.

The VAQ acts as a traditional limited-slip differential—which reacts by transferring a set amount of torque to non-slipping wheels when others lose traction—but adds to its effectiveness by monitoring the data from each wheel sensor at all times. Since this data includes both vehicle and wheel speed, as well as yaw and lateral g-force, the system constantly makes precise adjustments to help maintain an optimum torque balance between the left and right front wheels.

Up to a full 100% of torque can be transferred to either side, as opposed to the fixed “best guess” percentage seen in traditional limited-slip differentials. The result of this proactive (rather than reactive) system is the elimination of the understeer and torque steer that can afflict sporty front-wheel-drive cars.

The all-new Golf GTI also features the Progressive electric power steering system. Volkswagen has spaced the teeth on the steering gear’s rack more tightly towards the center. The lower steering ratio in the center means that the car responds more quickly when entering a turn, while the higher ratio at the ends of the rack reduces the amount of effort needed near full steering lock, such as when parking. The steering wheel goes from lock to lock in just 2.1 turns, whereas the standard Golf needs 2.76 turns.

Pricing for the all-new Golf GTI starts car starts at $24,395 for the entry-level S trim in two-door form with six-speed manual transmission, an increase of just $195 over the base price of the previous model.

May 30, 2014 in Engines, Fuel Efficiency | Permalink | Comments (0) | TrackBack (0)

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