You want speed? We’ve got it in the cosmos.
On Earth, if you live in the midlatitudes, Earth’s rotation is carrying you and the atmosphere you breathe sideways—due east—at about 800 mph. If you’re an equator dweller, that speed is 1000 mph. Santa, on the North Pole, has no sideways motion at all. His cottage simply pirouettes once per day.
Problem is, our planet rotates so smoothly that you don’t even feel it. What fun is that?
The rotating Earth also orbits the sun, in a nearly circular path, at about 67,000 mph. It moves so smoothly through space, you don’t feel that, either. What fun is that?
The sun, with its formidable gravitational force, drags all its planets, moons, comets, and asteroids with it, in orbit around the center of the Milky Way galaxy, at a rate of about 450,000 mph. Which means Earth’s planetary path, when traced through space, looks like a huge interstellar corkscrew. Another smooth, high-speed journey we don’t feel.
On brief reflection, we all can report that the larger the vessel we ride, the less we notice its motion. Anybody who has flown the bulbously large Airbus A380—an airplane that resembles what an anaconda might look like after it swallowed a pig—would surely note how smooth the ride was, all while the plane went to 600 mph and back.
So what are we really after in this issue of the magazine? What do we really want to experience, even if only subliminally?
In fact, what we really seek are rapid changes in our speed. Those who recite the fast-lane mantra “I feel the need for speed” almost surely instead mean “I can’t wait to accelerate.”
People who like the feel of going fast prefer a stiff suspension because it allows you to “feel the road,” which is driver’s code for feeling all the abrupt disruptions to what would otherwise be a smooth and steady ride.
In the formal language of physics, we go a step further: Acceleration is not only a change in speed (up or down) but also a change in direction. That’s why going around tight turns—especially banked turns—is vastly more fun than driving in a straight line. That’s why the most-fun roller coasters are not the ones that go fast, but the ones that flip, twist, and turn you incessantly.
Practically any car sold in America can hit 100 mph. Plenty can even hit a top speed of 150. So if all you wanted were speed in this world, you could get it cheaply. But what you really want is to minimize the time it takes to go from zero to 60. You want the ability to change direction at high speeds while maintaining control of the vehicle. You want the ability to brake quickly. You want to drift the car sideways at high speeds, as advertisements of sporty vehicles are compelled to show on television. These performance features garner premium prices in any car line.
And they are all exhibitions of acceleration—legal in most places across the universe.
|—Neil deGrasse Tyson|
Building Blocks of Speed: Tough Rubber
Strong tires are essential to attaining—and surviving—outrageous top speeds. The “(Y)” speed-rating category is where tire and car manufacturers collaborate to engineer rubber for speeds in excess of 186 mph. In addition to managing the extreme inertial forces that tug at treads, engineers strive to minimize contact-patch deflection and squirm, thereby avoiding heat buildup at speed. Robust tire construction, reduced load ratings, and high inflation pressures (adding up to 7.5 psi, depending on the speed and tire specifics) are the preferred approaches.
Building Blocks of Speed: Body Movin'
Movable aerodynamic bodywork is a technology that supercar constructors are exploiting to provide multimode performance. Wings, flaps, spoilers, ducts, and diffusers position themselves to provide airflow and downforce to aid braking, cornering, and stability. And when the pursuit is maximum straight-line speed, these components automatically reset to a lower-drag position. Bugatti used this approach nearly a decade ago for the shockingly fast and stable Veyron. Since then, Ferrari has introduced dynamic aero features on the 458 Italia, F12berlinetta, and LaFerrari. McLaren is on board with the 12C, 650S, and P1. Both ends of Porsche’s 918 are thus equipped.
Building Blocks of Speed: Shocking Performance
Electrification has infiltrated the supercar ranks. Torque-rich electric motors are great for augmenting a highly tuned combustion engine’s soft low end and for recycling waste energy during deceleration and braking. To exploit electric torque beyond 150 mph without resorting to an oversized battery pack, BMW, McLaren, and Porsche use a transmission to keep their motors spinning at an efficient rpm. BMW’s i8 has a dedicated two-speed automatic up front while McLaren (P1) and Porsche (918) blend gas and electric torque with their seven-speed dual-clutch transmissions.
Building Blocks of Speed: Slip Kids
Aerodynamic drag is a hungry beast that gobbles power and saps a vehicle’s vitality, which is why slipperiness pays dividends: The wind tunnel reveals, for example, that only 17 horsepower is needed to drive our long-term Cadillac CTS Vsport through the atmosphere at 70 mph. Overcoming friction and rolling resistance consumes additional power, but while those losses are directly proportional to speed, the aero component rises with the cube of velocity. In the Cadillac’s case, the 50 horsepower needed at 100 mph to overcome wind resistance rises to a significant 397 horsepower at 200 mph. This is why our CTS tops out at 171 mph.