Few larks seem more pointless – if entertaining – than an "ice-driving experience." Pirouetting over a frozen lake seems romantic, but hard-earned experience has proved to us that trying to make a crisp turn in a nose-heavy Aston Martin V12 is an exercise in frustration. Like an MMA fighter performing the cha-cha on "Dancing with the Stars," some concepts are best left unfulfilled.
Porsche, though, does a brisk repeat business at its five global ice-driving camps. It owes much of that success to its ice-carving tool of choice, the 911. For any adherent trying to suss the intricacies of weight transfers in that ever-evolving, rear-engine outlier, the ice holds answers.
Driving on a low-friction surface is the best place to get instant feedback on cause and effect, as close to driving in a vacuum as we're going to get. Any decisive input equals an effect, an easily quantifiable result: You either head in the direction you hoped for, or somewhere else – possibly a snowbank. (It also reminds a driver that simply bobbling the steering wheel and stabbing at the gas without express intent leaves the car a muddling mess and with no obvious trajectory at all.)
In North America, Porsche holds a February-long event at Circuit Mecaglisse, a dedicated track in the forests of Quebec. Coined Camp4 Canada, with prices starting at around $4,500, the two-day experience is overseen by a cadre of instructors, with the days broken into various handling exercises. This is its eighth season at the location. While the school once included seat time in the mid-engine Boxster or Cayman, the program now focuses solely on the 911, offering both 991.2 S and 4S models.
We spent only one day driving, but it was enough to realign ourselves with the 911. Though the engine creeps ever more inboard with every generation, it takes only one turn on an ice-and-snow skid pad to firmly remind that the 911 remains a rear-engine vehicle.
The weight on the rear means it is surpassingly easy to get the 1.5. mm-studded tires (Nokian Hakkapeliittas, in this case) to hook up, even on slick ice. But just as on asphalt, drivers must focus on getting the front tires to bite, either by trail braking or coming off the accelerator briskly, transferring weight to the front. And since you need to slide through corners, rally-style, aiming the nose at the exit early, the goal is to cleanly break the rear tires loose. This is achieved by abrupt lifts, left-foot braking or a dose of throttle. Or combinations thereof.
The sense of Porsche purity is exceptionally clear out here. Too often we have to "game" modern sports car's electronic management systems, filtering our own inputs through the logic of the computer. For instance, the RWD Lamborghini Huracan only allows significant slip angle in its Sport (and not Race) setting, with the throttle planted. Feather in and out of the gas, and the electronic controls snap the car back in line, interpreting minute throttle corrections as hesitations. It's a counterintuitive way to drift.
Porsche Stability Management (PSM) is fully and easily turned off with a long button press, and you're good to go play on the ice without undue electronic interference. But there is a small wrinkle: All 911 S models with PDK transmissions also come standard with torque-vectoring plus. The "Plus" system uses an electronically controlled rear differential to help apportion torque and also to brake an inside rear tire, helping the car bend into turns.
The torque vectoring still works when PSM is turned off. I imagined that the vectoring would interfere with the turn-in on ice, perhaps over-inducing skids. This wasn't the case. It works so seamlessly in the background that I was never consciously aware of it intervening whatsoever.
So, the greatest learning curve of the day came down to the difference in driving style demanded by the two model variants, the RWD and the AWD.
We began our day in a 4S on a skid pad. (The track is actually hard-packed ice and snow; the surface gets slicker as the top layer of snow is scrubbed away.) Inducing oversteer was easy, and the 911 is a supremely willing dance partner. I was soon steering mostly out of the side windows, feeling stylish indeed.
Still, I was continuously re-inducing the rear wheels to break away; a game of throttle stabs, oversteer and correction on endless repeat. An instructor, a Canadian karting champ, called me over and urged me to quiet my hands. He pointed out that I was treating the 4S like a RWD, going lock-to-lock, forever chasing the slide. The AWD system takes in a host of factors when deciding to apportion torque, but one is that it reads busy steering inputs as an attempt to regain control, so it directs more torque to the front wheels. (Unlike the Porsche SUVs, less than 50 percent of torque can be sent up front.) The front wheels pull the car out of the drift.
Instead, once you have broken rear traction, you need to keep your hands as open as possible, using slight corrections to change the angle of the skid, but otherwise using the right foot to either tighten the radius (by lessening the throttle) or increasing the radius by feathering in more gas. I stopped making big turns of the wheel and the AWD system balanced the torque more evenly, allowing long, continuous drifts. It is fun, but requires a rewiring of skills long learned from RWDs.
The 911's rear-bias also shows a happy application on the slalom. That weight in the rear makes for exuberant pendulum turns. Turn early, get the rear to break, trust that the lateral weight transfer is on its way and then get ahead of the next steering input. The car slides, pauses and then the rear swings, pointing the nose toward the next turn. Nail the rhythm and it's a delight.
So too goes the method for getting around acute 90-degree turns, using the Scandinavian flick. Hug the inside, abruptly lift off the gas, give a wheel tug in the opposite direction and then a full wheel turn in the direction you want to go, often with a short stab of gas. The 911 will make that pendulum turn with aplomb.
But the most fun still comes in the plain-old, rear-wheel 911 S. Steering inputs are far busier, often going lock to lock, and you're continually feathering the gas. It is the cha-cha you dream about. A driver is completely engaged, and it's one the reasons why you can't help but continue to love the rear-engine configuration.
One more note: Changing the sport settings (which are now on the wheel itself) also changes the throttle mapping. Unfortunately, this makes the gas more "responsive" in Sport and Sport Plus modes. In the slippery conditions, you want your gas pedal to be as finely tuned an instrument as possible – a rheostat, not a light switch. After cycling through Normal, Sport and Sport Plus modes, I went back to normal and left it there all day.
Final analysis: As the tires and resultant grip continually improve on sports cars, and the numbers of electronic aids multiplies, it gets ever harder to find the limits of adhesion on a car like the 911 – especially on any legal road. Even the lines between RWD and AWD can seem blurred.
Out at Mecaglisse, the rear-engine physics of the Porsche become obvious – unassailable even. Equally important, there are no real consequences when you get it wrong. Speeds are low and, hey, it's not your car anyhow. For anyone who wants to understand their rear-engine machine, Camp4 is not a lark at all. It's an education.
نویسنده : محمد رضا جوادیان بازدید : 5 تاريخ : سه
1396 ساعت: 10:56