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How Cars Have Gotten Quicker

By: · November 15, 2016

-We live in a no-waiting culture. From education to communication to transportation, everything in our lives seems to be getting quicker. And this certainly applies to our cars. Entire careers of-automotive engineers have been devoted to shaving tenth after precious tenth of a second off-the acceleration times of all the vehicles we drive, whether they be panel vans, family sedans,-econocars, or hypercars. So what constitutes quick today, and what developments have made today’s cars the quickest in history?--This content is part of The Genesis of Personal Discovery.-Back in 1965, C/D strapped our test equipment to a new Corvette Sting Ray—one of the quickest cars of its day—and it blasted to 60 mph in 6.2 seconds. Fifty years later, 6.2 seconds was the average zero-to-60-mph time among the 328 2015 model cars we tested, with more than a few surprising performances turned in by cars such as the 2015 Volvo V60 T6 R-Design-wagon (4.9 seconds), the 2015 Ford F-150 Platinum 3.5L EcoBoost 4WD SuperCrew (5.6 seconds), and  the 2015 Toyota Camry XSE V-6 (5.8 seconds). What about the new Corvette? Over the past 50 years, it has cut its time in half, thank you, to three seconds flat in 2015 (that’s for  the 650-hp Z06 model  with the Z07 package).-For stronger off-the-line acceleration, torque—as opposed to horsepower—is really what you’re after. And when it comes to generating torque, there’s an old adage that says, “There’s no replacement for displacement.” In this context, displacement refers to the total swept volume of the pistons moving up and down inside the cylinders. The greater that space, the more air and fuel can enter it during the intake stroke, resulting in more powerful combustion once it’s compressed and ignited. Displacement can be increased by increasing cylinder diameter (bore), by lengthening the piston strokes, or both. Cars got quicker through displacement increases particularly during the 1980s, 1990s, and early 2000s, when gas was cheap and fuel-economy regulations weren’t as strict as they’ve become.-While there may be no replacement for displacement, turbochargers are an increasingly-common way for carmakers to quench our thirst for power without adding cylinders or-increasing the displacement of existing ones. Turbochargers make cars quicker by forcing more-air into the cylinders during the intake stroke, and that extra air allows additional fuel to be injected as well, resulting in more energy released during combustion. The primary components of a turbocharger are a turbine in the exhaust system connected by a common shaft to a compressor wheel in the intake system. The exhaust gases spin the blades of the turbine, sending it and the compressor wheel spinning at the same rate. As the exhaust gases drive the turbine, the compressor shoves more and more air into the cylinders. Maximum-power flows only after a short period of “turbo lag,” but once it’s spooled up, power rushes in like a tidal wave.-Like power yoga instructors for your car, engineers have helped make cars both quicker and-more efficient by focusing on their breath. Today, even the lowliest of subcompact cars breathe-easily through four valves—two intake and two exhaust—for every cylinder, and most modern-engines have the ability to advance and/or delay the opening and closing of both the intake and exhaust valves. Aerodynamicists have mastered the craft of directing airflow into the engine bay—sometimes through active aero shutters—allowing engines to gulp in as much fresh, cool air as they need but no more. Exhaust systems have also evolved to reduce back pressure through the pipes, emissions components such as the catalytic converter, and mufflers.-One major change that has taken place in recent years is the proliferation of dual-clutch-automatic transmissions, which are selectively used in place of conventional automatics. Dual--clutch automatics hand off the power flow between two clutch discs, which significantly reduces the interruption of torque to the wheels between shifts. (Traditional automatics put the power flow on pause for a fraction of a second during gearchanges.) As relatively new as they are in automotive applications, dual-clutch autoboxes don’t always operate too smoothly, but the best ones, such as Porsche’s PDK and Volkswagen’s DSG, effectively reduce shift times to zero. And with complete control over the clutch application electronically, they also enable the most effective launch-control programming.-Only recently has electricity been viable as a power source for modern cars. A major selling point of an electric car is its emissions-free operation, but since electric powertrains deliver maximum torque from a dead stop, some EVs, such as the Tesla Model S P100D with its Bugatti Veyron-like zero-to-60-mph time of just 2.5 seconds, are stupid quick, too. Hybrid and plug-in-hybrid vehicles also use electric motors, mostly as supplements to hyperefficient gasoline engines to achieve heroic fuel economy. Some current and former hybrids, however, such as the Ferrari LaFerrari, the Porsche 918 Spyder, the McLaren P1, and the BMW i8, use electric motors mainly to further performance credentials (although their fuel economy also tends to improve over that of non-hybrid supercars), where the instant-on power delivers acceleration that is—pardon the pun—utterly shocking.-Most of us consider cars to be mechanical objects, which, for much of the automobile’s existence, is what they were. But nowadays, cars are basically computer networks with wheels,-and some of their onboard brainpower is devoted to making them quicker. Electronics control-aero shutters and valve timing to increase airflow into and out of the engine; electronics control-the pulses of fuel through the injectors and the timing of the sparks that ignite it, all of which is done to optimize output as well as efficiency. Most cars now feature electric power-steering systems and thus have ceded the constant horsepower draw that was previously required by hydraulic steering systems back to the engine. Variable shock absorbers, including the trick electromagnetic shocks found in Corvettes, Cadillacs, Ferraris, and Lamborghinis, use electronics to balance the typically competing desires of ride and handling. Even ABS-based electronannies such as traction and stability control—initially the bane of performance drivers everywhere—have better justified their existence by being less intrusive and smoother in application should traction be compromised.-A car can have all the power of a nuclear reactor, but it is no use if it can’t get that power-to the ground. And as cars became more and more powerful—especially as exotic cars began to make truly ridiculous power—it became clear that sending it all to one axle—even with foot-wide tires—would no longer do. Hence, in the 1980s and 1990s, cars such as the Lamborghini Diablo VT and the Porsche 959 started using all-wheel drive to set new performance benchmarks for their brands and the industry alike. All-wheel drive also helps make such prodigiously endowed cars drivable in wet and snowy conditions that might otherwise immobilize them. Among the truly quick cars available today—say, all the ones that can hit 60 mph in less than four seconds—a huge number use all-wheel drive.-Wheelspin can be a hoot when you want to impress your friends on a Saturday night, but if-you’re racing for the pinks, you need to get out of the box right now. Imagine losing your new-Dodge Challenger Hellcat to some yahoo in a Subaru WRX STI with less than half the power, all-because you couldn’t get the tires to hook up when the tree went green. Fortunately, the 707-hp-Hellcat and many other high-performance cars have launch-control settings that make hero-making (and pink-slip-saving) launches so easy, your grandmother could do it. While actuating-launch control varies slightly from model to model, each essentially works in roughly the same-way, prompting the driver to keep one foot on the brake pedal while flooring the gas-pedal—classic brake torquing—with the computer limiting engine revs to the specific rpm it-deems optimal for tire hookup. Simply releasing the brake while keeping it floored-sends the vehicle hurling toward the traps (or the next stoplight) with minimal wheelspin and a-mischievous grin on the driver’s face. Especially if it’s Grandma.-While most of what we’ve discussed so far has helped our wheels turn quicker over the years,-the cars wouldn’t move any faster if those black rubber tubes wrapped around those wheels-couldn’t handle it. Admittedly, most people don’t know all that much about tires, but we’ve-learned a lot by performing tire comparison tests—and even slicing them open—to unlock some of their mysteries. And what we’ve learned is that, in essence, if we are acceleration junkies, tires are our enablers. With carmakers choosing wider and lower-profile tires, even on comfort-oriented cars, there’s more grip to handle today’s more powerful engines. Advancements in tire technology and construction have dramatically increased the cornering and braking performance of today’s vehicles.-It should be no surprise to anyone that one of the greatest reasons cars have gotten quicker is-because there are crazy men and women who make speed not just their hobby but their livelihood. It’s fun to watch fast cars driven fast, but professional motorsports are not-just about swaggering drivers, adoring fans, and checkered flags; they are also important test beds for new technologies that have to do with getting up to speed as fast as possible and staying there as safely and efficiently as possible. If a racing team is sponsored by a major automaker, or if a race car has an automotive supplier’s sticker on its fender, you can bet that at some level, it will be used to help that company learn about how their products fare at the limit. And when they apply what they have learned, cars get quicker.-because we have crazy men and women that make speed not just their hobby but their entire-livelihoods. However fun it is to watch fast cars driven fast, professional motorsports are not-just about badass drivers, adoring fans, and chequered flags, they are also important test beds-for new technologies that have to do with getting up to speed as fast as possible and staying-there as safely and efficiently as possible. If there’s a racing team that’s sponsored by a major-automaker, or race car has an automotive supplier sticker on its fender, you can bet that at-some level, it will be used to help that company learn about how their products fare at the limit.-And when they apply what they have learned, cars get quicker.

           

Filed under: Engine,News,Transmission

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