I'm bombing around Hollywood on a Saturday night in an all-electric Tesla Roadster, a sick-with-torque, carbon-fiber mosquito with a half-ton of glorified camera batteries behind the seats. It's a perfect night for cruising, cool and moonlit. The city lights drizzle over the silver car like Campari and creme de menthe.
As I nick down Vine, a Porsche Carrera C4 takes up a flanking position to my left and raps his engine -- a thick, ornery staccato rises, a murder of gas-powered crows. I, of course, have no engine to rap. The electric buzz the Tesla produces at low speed sounds like a toaster with a bagel lodged in it. I shrug sheepishly in the direction of the Porsche driver, sequestered behind tinted glass.
I turn west on Sunset and he follows me. He puts the Porsche door-to-door with the Tesla and guns the flat-six again. Oh, I get it. He wants to race to the next light. That's too bad for him.
What transpires in the next 2 seconds is the heart and soul, the essence and spirit, of the Roadster. This is the trick this one-trick pony does better than perhaps any sports car on Earth. We in the business call it "rolling acceleration."
At about 20 mph I nail the go pedal, and the power electronics module summons a ferocious torrent of amps, energizing the windings of the 375-volt AC-induction motor. Instantly -- I mean right now, like, what the heck hit me? -- the motor's 276 pound-feet of torque is converted to dumbfounding acceleration. Total number of moving parts: one.
Street lights streak past me like tracer bullets. My little mental circuits go snap-pop with the thrust. God has grabbed me by the jockstrap and fired me off his thumb, rubber band-style. Wow.
Meanwhile, over in the Porsche, 19th-century mechanical forces are taking their own sweet time. The driver has to clutch, shift to a lower gear, and de-clutch -- a regime that takes about half a second if he's talented. When he pushes on the accelerator pedal, the throttles in the Porsche's throat open, the fuel injectors start hosing down the cylinders with high-test, and the variable-angle cams rotate to maximize intake-valve duration. The flashing fire in the cylinders can now apply its maximum force to the pistons.
But it takes precious milliseconds to overcome the inertia of the engine's reciprocating masses -- the pistons, the rods and the crankshaft -- and to convert that force to torque (rotational force). Then that torque must pass through the clutch assembly and transaxle, and ultimately to the wheels, where it eventually gains leverage against the car's overall mass. Only now is the Porsche accelerating.
