”If we had P90D, 800 km/500 mi would be very likely,” said Bjørn Nyland, one of the drivers, in an email, referring to the newest Model S variant that has a higher EPA estimated range. “Using a P85D was not a coincidence. The front motor and inverter is smaller and more effective than the bigger rear motor,” he said. “When using ‘Range Mode,’ it enables torque sleep. The car will figure out which motor to use. Sometimes it’s a rear wheel drive. Sometimes it’s a front wheel drive. And sometimes four wheel drive. During this hypermiling, it was basically a front wheel drive,” he added.
* no air conditioning
* mostly flat roads
* driven at 39 kph or about 24 mph
SOURCES - Forbes