The PTU can switch between the two gears in about a tenth of a second, and it chooses its gear ratio solely base on what the rear transmission is doing: in first and second gears, the PTU is in its low range. In third and fourth, it’s in its higher range. In fourth through seventh, it’s disengaged completely. Is it a problem that the FF can’t engage the front wheels in top gear? Well, when was the last time you ran out of traction on the highway in top gear? Right, never. Fourth gear -- and therefore the front-wheel drive -- is good for 133 mph, and that’s likely fast enough for even the most insane snow drifters. Like your author.
With enough computing power to launch a fleet of space shuttles, the whole system (which also includes Ferrari’s rear E-Diff limited-slip differential) is called 4RM, which stands for 4 Ruote Motrici in Italian -- or 4 Wheel Drive. It’s an evolution of the predictive system in the GTO that watches each wheel’s speed (and the car’s overall attitude) to predict how much traction is available at each individual corner.
Ferrari repeated over and over (and over and over!) that the four-wheel-drive system is not used to enhance performance in the dry, only to increase the FF’s usability in bad conditions. We call that line of spin BS. We’re not sure why the company is so insistent upon this, but we suspect it’s so Lamborghini can’t say “Ha! Told you so!” The system works flawlessly in the dry, turning first- and second-gear hairpins that would normally be a festival of wheel spin into perfectly controllable four-wheel drift-a-thons.
Cars like the Nissan GT-R and Mitsubishi Evo have proven that sophisticated computer controls have made Four Wheel Drive no longer a Four Letter Word as far as handling is concerned. Those two cars, previously the champs in this regard, use four-wheel drive to mask an inherent weight-distribution problem -- and their AWD systems add a tremendous amount of weight. Not so the FF. Through brilliant engineering, it maintains all of the handling prowess and (relative) light weight of a rear-wheel-drive Ferrari with no drawbacks.