Many SUVs have moved from the traditional truck-like body-on-frame design to wagon-like crossover setups. As many share a platform with sedans and wagons, those AWD setups become the only option, but have proven their mettle. They have also become quite advanced. Power can be sent from front wheels to back and/or from left to right sides. When slippage is felt in one wheel, power is sent to the other three. Depending on the system it may only send partial power, while others can send 100% power from front to back.
And why do we need these advanced systems? Between the frost heaves, black ice and white out conditions, driving in a winter storm can be quite the endeavor. Often we don’t have the luxury to wait for the storm to pass over or for the plows to get there. Sometimes, you need to get there, regardless of the conditions.
To simulate a potential sliding situation, we embarked upon skid pad made of ice. Our vehicles were the Porsche 911 Carrera and the 911 S. Both are rear drive cars, we are certainly going to spin, the lesson here is how to recover. Most commonly you under steer, or “plow.” That’s the terrifying feeling of turning the wheel and nothing happening as you careen towards the woods.
In real life, too much braking causes this, and in some rare cases too much acceleration. The key here is to layoff whatever pedal you’re stamping on. Gunning it won’t help– that moment of neither braking nor acceleration, is where you look in the direction you want to go, and turn the wheel.
On the skid pad, these factors came to bear, as you were encouraged to accelerate by an instructor, riding shotgun. In that moment, as I am encouraged to build speed and momentum, the fates of driver and instructor were intertwined. As speed built and I turned the wheel and nothing happened, I was instructed to ease off the throttle and as the car slowed the wheels caught and it executed the originally intended turn. The 911 S did this, but with 400 horsepower, it took very little throttle to break free, only to catch grip again with rear tires that were several inches wider.
Once complete with the skid pad we headed to the “track.” It was a circuit of snow that had been packed down with a Sno-Cat. This course would be navigated with the all-wheel drive 911 Carrera 4S. It has the same 400-horsepower 3.8-liter flat-six, but with the added capability of Porsche’s all wheel drive.
On this course, we were encouraged to maintain smooth driving as a means of minimizing slippage as we rounded turns. The limits of breaking the back end free realized from the skid pad test would linger on the first lap, but quickly faded as the 911 showed its mettle, handling turns with a 4×4-level of control. Entering the turn, you start wide, ease off the throttle and into the apex– accelerating out the other side. It was hard to imagine that a sportscar could demonstrate such control in such very un-sportscar conditions.
According to lead instructor Cass Whitehead, the new AWD system is predictive where old systems have been reactionary. The predictive systems are able to achieve this oracle-level pre-notion by meaning steering throttle and brake inputs,, and matching that with established algorithms for a normal driving model, when it thinks something is up, it goes to work, putting power and taking away where it sees necessary.
The most advanced all-wheel drive systems and latest tire tech will not overcome the worst winter drivers or worst that winter can throw at the road. For those moments when it relies on the driver, just remember to be calm, and laying on the throttle or brake will not help. According to Cass and his instructors, as long as you “Correct, pause and recover,” you will give yourself that extra moment to thing about your next move and hopefully, get back in control and out of trouble.