Update: All Tesla Model S cars produced after September 29, 2014, come equipped with new driver assistance hardware and software, allowing lane keeping assistance and adaptive cruise control. Tesla announced the new driver assistance features at an event in Los Angeles.
An unearthly amount of grip held the car through the twisty strip of asphalt running along the side of a forested mountain, and when I got on the accelerator for the turn exits, I was rewarded with instantaneous power, as much as the car and my own instincts could handle. If this were a typical car, I might have gotten good response on the throttle if I had the proper gear, but the power delivery would fluctuate as the engine speed changed.
But this wasn't any typical car: it was the 2014 Tesla Model S in Performance Plus trim. Pushing the accelerator at any speed led to instant twist at the wheels, all the energy that could be released from the 85-kilowatt-hour lithium ion battery pack to the 310-kilowatt motor, turned to kinetic force at the rear wheels.
Gasoline-engine cars, with their complicated dance of fuel-air mixing and ignition to push pistons and turn a crankshaft, can't achieve the kind of direct power response afforded by the Model S' drivetrain. And it all comes down to simplicity. With fewer processes between stored power and putting rubber to the road, the electric drivetrain is naturally more efficient than the internal-combustion engine, about 90 percent versus 35 percent.
Beyond the merely theoretical, you can actually feel that superior power conversion at the accelerator. The fact that the Model S needs only a single ratio reduction gearbox, as opposed to a transmission with multiple gears, demonstrates the more direct conversion of energy afforded by the electric drivetrain.
Vive la différence!
The difference between electric and internal combustion engine wasn't lost on Tesla's engineers. They used the drivetrain's unique characteristics to rethink the whole concept of the automobile for the Model S, significantly changing how you interact with the car.
As one example, there is no key for the Model S. Neither is there a start button or a parking brake. All these things are legacies from the last century of motoring, made unnecessary by today's technology. Walk up to the car with its Model S-shaped fob in your pocket, and it unlocks, the door handles automatically extending.
Getting into the Model S makes the instrument panel and the massive, 17-inch center touchscreen light up. Set the steering column-mounted drive selector to D, push the accelerator, and you're off. Similarly, putting the car in Park and getting out effectively turns it off. Walk away or push a button on the fob, and the doors lock.
It takes a little getting used to, but the Tesla Model demonstrates 21st century driving.
While pushing the accelerator gives direct access to the stored power, lifting off makes the car slow as if you were pushing the brake pedal. That's regenerative braking taking hold in a style other automakers now call one-pedal driving. On freeways, I never actually had to touch the Model S' brake pedal, as lifting off the accelerator slowed it enough to cope with slower traffic ahead. On city streets, I didn't have to touch the brake pedal until the Model S was down to about 3 mph, if I judged the distance to stopped traffic ahead well.
As I drove the Model S over a variety of roads and at differing speeds, it occurred to me that Tesla engineers also did a remarkable job of tuning the accelerator modulation. Backing into a parking space, just a little pressure on the pedal gave me excellent control during low-speed maneuvering, the drive systems letting only a bare trickle of the electrons flow to the motor.
Holding suburban speeds, 35 to 45 mph, proved easy enough, but my favorite part of the throttle cycle involved tipping it in beyond 75 percent. Like a rocket on electric rails, the Model S bolted forward, the juice flowing to a point where I could feel the tremendous momentum taking over, a visceral example of Newton's first law of motion.
And if I had the guts -- or enough open road ahead of me -- holding that throttle position kept up the acceleration. Tesla notes that the Model S, in Performance Plus trim, hits 60 mph in 4.2 seconds, a time even more impressive when you consider the car's 4,647-pound (2,108kg) curb weight.
Those people not ready for this new driving paradigm can make the Model S perform a little more like a traditional car. Pull up the drive settings on the center LCD, then switch Regenerative Braking to Low and turn Creep to On. These settings let the Model S coast more easily and make it crawl forward as soon as you lift off the brake, just like a gasoline engine car with an automatic transmission.
Considering other more traditional automotive attributes, the Model S rides as it looks: solid and elegant. Air-cushioned dampers help soak up the road, but that doesn't mean a soft ride. There is no excessive bounce in the suspension, just the dampers and springs maintaining the car's composure. To enhance aerodynamics, the Model S automatically lowers at freeway speeds, and you can set the suspension to a high position when negotiating speed bumps or other obstructions.
The drive settings let me choose from Sport, Standard, or Comfort for the electric power-steering program, going from a good amount of heft to easy, one-handed turning. In each setting, the response was precise but also a little numb, the sort of point-and-shoot feeling that often comes from electric power-steering programs.
The Performance Plus package includes heavy duty dampers and sway bars, which I enjoyed as much as possible on twisty back roads. The Model S feels heavy from behind the wheel, and I expected that to make for clumsy handling when really pushed. Instead, the car held its own extremely well, its 48/52-percent weight balance between front and rear wheels taming understeer while the big, Michelin PS2s on 21-inch wheels gripped the asphalt. The Model S could not so defy physics as to rule out load shift in the turns, and it wasn't light enough that I would call it nimble, but I couldn't get it to break grip.
The Performance Plus trim adds more to the Model S than suspensions upgrades, not the least of which is price. The example I drove, fully loaded out, came in at above $120,000, almost twice that of the base Model S with a 60-kilowatt-hour battery pack.
Tesla upgrades the electric motor in Performance Plus to 310 kilowatts, producing 443 pound-feet of torque, from the base model's 225-kilowatt motor and the 270-kilowatt motor in the middle-ground 85 kilowatt-hour Model S.
The US Environmental Protection Agency (EPA) puts the range for both the Performance Plus trim and standard 85-kilowatt-hour battery pack at 265 miles, and 208 miles with the 60 kilowatt-hour battery pack. The EPA gives an mpg equivalent figure of 89 for the Model S, which serves to show how efficient the car is compared to gasoline-engine cars, but little else.
Another number that might prove more useful is the EPA energy usage of 38 kilowatt-hours per 100 miles. The Model S' trip computer showed I handily beat that rate, even with a fair amount of fast starts and mountain driving, turning in 33 kilowatt-hours per 100 miles over a few days' driving.