Monday, 27 June 2016
Mazda’s G-Vectoring Control: Effective, But Not What Its Name Suggests
http://ift.tt/29hyybb
from Car and Driver Blog http://ift.tt/291zjI6
via IFTTT
Read More...
Lets face it, the current automotive climate breeds lazy drivers (see automatic cruise control, lane-keeping assist, and the decreasing availability of manual transmissions). So it seems incumbent on us to celebrate genuine advancements that improve a driver’s ability to actually control a car with one’s own appendages, whether while going fast on a racetrack or just taking the family to the beach. There’s an interesting new one over at Mazda, where the driving forecast is sunny.
The brand from Hiroshima ranks remarkably high on the overall fun-to-drive scale, especially considering its size and resources. The Mazda 3 and the MX-5 Miata reside on the current 10Best Cars list and the Mazda 6 is a previous winner. The company’s SUVs drive like cars, and its interiors deliver visual punch a weight-class above their prices. In short, Mazda cares about making cars that people actually find enjoyable to drive themselves, which is why we flew to Mazda Raceway Laguna Seca, outside of Monterey, California, to go around the track at a mere 30 mph. Mazda wouldn’t even tell us what G-Vectoring Control (GVC), the technology it planned to showcase, actually was before letting us sample it in the 2017-spec Mazda 6.
The day started with laps of an impromptu oval in the parking lot at a blistering 20 mph. An engineer would switch the Mazda 6s between GVC active and GVC off from the passenger seat. At first, GVC just feels as if it makes the steering a little heftier. But after a few of these cruise-controlled laps while hugging a line of pylons, we realized that turn-in is smoother and rarely did we have to correct our driving line. Watch this video to see the difference, paying attention to the white line on the steering wheel:
But we were still in the dark about what GVC actually does. Given the name, you might expect it to be some kind of torque vectoring, or steering the car by controlling differential torque delivery between the inside and outside wheels in a corner, which is analogous to how tanks turn. But that’s not what GVC is doing. Mazda finally explained that the important part of GVC is the G, or as you see it frequently, g. By closely monitoring the speed of the driver’s steering-wheel inputs, GVC tells the engine to ever-so-slightly reduce torque. This produces an imperceptible deceleration, only 0.05 g in the most extreme cases. (By way of comparison, lifting off the throttle in a typical car results in about 0.20-g deceleration.) The tiny change generates a small shift in load to the front axle, which tightens everything in the front suspension and steering system, removing compliance in bushings and dampers and resulting in improved steering response. It is remarkable how such a tiny influence can contribute such a dramatic change. Engineers hesitate to quote a lb-ft figure but they did confirm that GVC reduces engine torque by a single-digit percentage, usually by retarding the timing. At a steady 20 or 30 mph, the 6’s 2.5-liter might be putting out 20 lb-ft, so even 9 percent would be less than 2 lb-ft reduction.
The whole project was eight years in the making and it developed out of an extensive study of how humans move and how, when controlling cars, drivers make similar movements and react to g forces. After proving the concept with an EV—used because electric motors allow ultra-fine control of incremental torque delivery—Mazda had to wait for its range of Skyactive engines to reach the mainstream before developing the technology for production cars. Mazda’s newest engines have granular and rapidly responsive control over torque output. Creating the slight deceleration is one thing, but getting it to happen in a small amount of time—0.05 seconds—so that the driver and passengers wouldn’t notice, is the real key to making GVC appear seamless to occupants.
Essentially, GVC mimics techniques, like “breathing” the throttle or left-foot braking into a corner, that race and rally drivers use to generate more front-wheel grip and get their competition cars to turn, only it’s extremely subtle, never felt or obvious. While going fast is always a hoot, GVC is more of a comfort- and confidence-builder than anything else. It will not improve skidpad grip or shave seconds off of any driver’s fastest lap time.
After explaining what GVC does, Mazda had us lap Mazda Raceway at 30 mph, hugging the inside edge of one corner to stay on the same line while an engineer in the passenger seat switched the GVC system on and off, as we’d been doing before on the parking lot oval. From the driver’s seat, there are fewer corrections needed, particularly when making quick changes in direction, when a driver might otherwise crank in too much steering angle. With GVC at work, you’re less likely to over-shoot your steering input because there’s less delay caused by the previously mentioned compliance that’s baked into the front suspension and steering. That compliance is there to improve ride quality and reduce noise (racers often replace the bushings and mounts with stiffer elements to improve responsiveness, trading away comfort in the process). From the passenger seat of a Mazda 6 with GVC, we clearly could see other drivers making fewer small steering corrections. This limits head toss and torso movements significantly for all occupants. Fewer corrections also reduce driver fatigue, again, improving comfort.
Mazda also simulated a narrow-lane construction zone using tall cones and Jersey barriers on Mazda Raceway’s front straight. Many drivers never notice it, but going dead straight requires that they make a lot of little steering corrections. With GVC turned on, these corrections become less extreme and fewer in number, again reducing driver fatigue.
The really difficult part for Mazda is conveying this information to the car-buying public. The finer points of how GVC works will be lost on most customers, which is not really a problem in itself. All they need to understand is that GVC improves an already class-leading steering system, making for a better-driving car. GVC comes standard on both the 2017 Mazda 3 and 6, and we expect to see it proliferate across the rest of the Mazda lineup within a few years. The Mazda MX-5 Miata is one model that may never get GVC because its suspension has less compliance and a lot of anti-lift baked into its geometry. But we have no doubt that Mazda will find other ways to make that car even more fun to drive in the coming years.
from Car and Driver Blog http://ift.tt/291zjI6
via IFTTT
Base-Model Mercedes-AMG GT Brings Price of Entry Down by $20,000
http://ift.tt/299hGoj
from Car and Driver Blog http://ift.tt/28Z67hO
via IFTTT
Read More...
Mercedes-AMG is filling out its sports-car lineup with two new versions of the AMG GT coupe. The hard-core AMG GT R certainly is the most exciting bit of news, but we shouldn’t forget the arrival of a new base model that offers a lower entry point for this sexy, V-8–powered two-seater. Starting at $112,125, the “entry-level” AMG GT goes on sale late this summer and is slightly less powerful and less well-equipped than the AMG GT S that’s been on sale in the U.S. for about a year.
Powered by the same 4.0-liter twin-turbo V-8 as the GT S, the GT gives up 47 horsepower and 36 lb-ft of torque to its big brother. But performance doesn’t drop off much, with Mercedes estimating a 0-to-60-mph run of 3.9 seconds (0.2 second slower than the S) and a top speed of 189 mph (4 mph behind the S). However, our test of the GT S blew the manufacturer estimate of the water with its 3.0-second run to 60 mph, so we’ll see how the GT does on the track when we get one in to test.
Less means less when it comes to the AMG GT’s standard equipment list, which does without the GT S model’s Nappa leather seats, AMG adaptive exhaust, Burmester audio system, adaptive suspension, and red brake calipers. Some of these features should be optional on the standard GT, however, and things like a backup camera, keyless start, power memory seats, and a limited-slip differential are still included. Thank goodness.
from Car and Driver Blog http://ift.tt/28Z67hO
via IFTTT
2017 Cadillac ATS Loses Base Engine, Gains More Feature Content
http://ift.tt/1rZehiE
from Car and Driver Blog http://ift.tt/28Y2KLx
via IFTTT
Read More...
June 27, 2016 at 12:26 pm by Greg Fink | Photography by Michael Simari
The 2017 Cadillac ATS sedan will enter U.S. showrooms this summer with one less engine option for consumers to choose from, as the former base 2.5-liter four-cylinder engine is going the way of the dodo. In its stead, the brand’s 272-hp 2.0-liter turbocharged four-cylinder engine will now serve as the the entry-level powertrain, as it currently does in the ATS coupe. A 300-plus-horsepower V-6 remains optional.
With a base price of $35,590, the 2017 Cadillac ATS sedan’s starting price rises by $1380 but also includes such features as Cadillac’s CUE infotainment with an 8.0-inch touchscreen, Apple CarPlay and Android Auto, a Bose surround-sound audio system, and a rearview camera. These features appear on the base Cadillac ATS coupe as well.
Despite the entry-level car’s higher price, Cadillac promises all other ATS trim levels—Luxury, Premium Luxury, and Premium Performance—will offer more feature content at less cost, with Automotive News reporting that 2017 models will be priced between $650 and $1100 lower than their equivalent 2016 counterparts.
It’s no secret that ATS sales have failed to catch on fire, and Cadillac has high hopes that the additional value baked into the 2017 ATS will spur more customers to the brand’s BMW 3- and 4-series fighter. Still, with year-over-year sales of the ATS down by more than 23 percent through May, clearly something needs to be done to spur interest in Cadillac’s entry-level sports sedan and coupe. Cadillac recently pulled the plug on its ELR plug-in hybrid after a hefty price cut and trim adjustments failed to result in customers driving out of its showrooms in the low-slung gasoline-electric coupe. Let’s hope a similar fate doesn’t befall the ATS.
from Car and Driver Blog http://ift.tt/28Y2KLx
via IFTTT