Can Big Engines Survive the Efficiency Onslaught?

The V8 now competes against twin-turbo V6s and tuned up four-cylinders that get markedly better efficiency.

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I’ve driven nearly everything out there, and I’m still not convinced that there will ever be a replacement for the glorious V8 engine. Case in point: the 2015 Chevrolet Corvette. It has all the baseline boxes checked: It’s low and wide, which improves cornering and lends an aura of menace to the machine. It has a fast electronic suspension and stability management system, so it stays surefooted no matter how ham fisted you are in the turns. Also, its transmission has active rev-matching to sync up engine speed with your gear selection for smoother shifting. It’s a complicated car throughout, but it’s the Corvette’s marvelous, mellifluous LT1 engine that is the true beauty.

When your gas pedal is mashed to the floor, the tachometer racing up the scale with every shift, a V8 uses simple, raw power. It gives off a sound, rich and sonorous, that doesn’t rattle your fillings the way higher-revving engines do. It’s not a twin turbo V6, such as you’ll see in the upcoming Ford GT and Acura NSX supercars, and which many would argue is the “new normal” in this age of hyper-efficiency. Nor is it an inline-four — though many cars produce crazy amounts of power from those plants — or, on the other end of the scale, a huge V10 or V12. Other engines don’t have quite the same panache. In fact, they can be scary — too high-strung, too tense.

How the V8 Shines

There’s a reason the V8’s simple acoustic note resonates so well among engine enthusiasts. According to Jordan Lee, the chief engineer behind Chevrolet’s version of this long-revered automotive staple, it can be traced to cylinder-firing sequences. “There’s a unique component of a V8 engine that’s different from a 4, 6, 10, or 12,” he says. “Every time there’s a revolution, the engine fires four cylinders, and that translates into noise from the exhaust. If it’s engineered correctly in terms of time delay between each firing, then that particular frequency is really like music. It’s extremely pleasant to the human ear.”

Other engines, he explains, just don’t have that same unique quality. If there are more cylinders, for instance, their sounds blend together. Fewer cylinders tend to be more raucous.

“A big V8 is exhilarating — it provides an incredible amount of torque force on the body, as well as an equal noise sensory overload,” notes race driver Rhys Millen.

Of course, aural satisfaction is not reason enough to favor a particular engine size when designing a car, and indeed V8’s deliver abundantly where it truly counts: performance. The sample in the ‘Vette I drove has the best tech Chevrolet has to offer: Active fuel management, direct injection and variable valve timing, all of which help crank out 460 horsepower and 465 lb-ft of torque without obliterating your fuel tank. Displacement, however, is the truly compelling statistic with this engine — all 6.2 liters of it. It’s the reason big engines have always had a performance edge over smaller ones, even those with turbochargers. And it’s the reason they’re here to stay, even with electric motors sparking at their heels.

Here’s a bit of conceptualization. The car’s engine is not a giant fuel pump. Rather, it’s an air pump. The displacement of an engine refers to the amount of air it pulls into the cylinders on every cycle. Fuel is simply squirted in to ignite that air — but in larger amounts if the cylinder size is larger. The resulting detonation push the cylinder down, generating power. In a large-displacement V8, there’s a huge gulp of air, and it’s repeated thousands of times every minute. In fact, just one minute at full boogie in a Corvette sees its engine draw in 37,000 liters of air, efficiently exploded to keep you rocketing toward the horizon via the significant torque and power the system generates.

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A cutaway drawing of the Corvette LS1 V8.

The difference in engine sizes mostly comes through responsiveness. “Smaller-displacement engines must rely on boosting via turbochargers or superchargers, and it takes a bit of time to boost air into an engine,” Lee says. So a large-displacement engine produces more power and torque at every RPM, Lee continues, and as a result it’s easier to drive fast and it can get out of corners faster when you apply the throttle. It simply doesn’t have to work as hard to deliver the goods, and that power feels good. “A big V8 is exhilarating — it provides an incredible amount of torque force on the body, as well as an equal noise sensory overload,” notes race driver Rhys Millen, cohost of Shut Up and Drive on Fox. “Coupled together, this can make a V8-powered car feel twice as fast as any standard engine.”

What the Big Engine Is Up Against

Efficiency is a huge motivation today, and not just for appearances. Engines now need to fall in line with government-mandated fuel-economy standards. With that in mind, even new supercars, such as the aforementioned Ford GT and Acura NSX, are favoring blown V6’s over traditional V8’s. This is par the course for Acura — its original version was also a V6, albeit a non-turbocharged version — but it may be deemed a step down for the Ford. The GT of yore (as in 2005) was a 5.4-liter V8 that produced 550 horsepower at 6,500 RPMs and 500 lb-ft of torque at 3,700 RPMs. The new, smaller 3.5-liter engine will exceed its namesake in horsepower, with 600 or so on tap, but will probably equal it in torque. The power-to-weight ratio is said to be excellent, though it remains to be seen if the car will have the responsiveness of its V8-powered predecessor. It will definitely best its fuel economy, which was only 14 MPG combined in the 2005 version.

To see who’s truly pushed the six-cylinder engine for all its worth, one need look no further than Porsche. With the exception of the V8-powered supercar 918 (a hybrid, as well) and the Panamera GTS, all of its models are six-cylinders, some turbo, some normally aspirated, all ranging from 2.8 to 4.0 liters in displacement — and nobody seems to be complaining about that. Indeed, the company, a bastion of bleeding-edge innovation, deploys every trick in the book to make its cars powerful and competitive. I spoke with the insiders at the company — which publicly “withdrew” from the horsepower wars recently, opting instead to focus on engineering strategies for reducing weight and boosting power efficiency — and they emphasized the relentless quest to squeeze every watt of power out of every drop of fuel. Strategies include lightweight materials to minimize mass in the moving parts, the most advanced variable-valve timing to precisely control engine breathing, high-tech coatings to reduce friction, and the most efficient lubricants for every vehicle and purpose.

For enthusiasts of big engines, there’s fortunately less and less reason to rue their fate as some sort of technological dinosaur.

In the new 911 Carrera 4 GTS I recently drove, that manifested itself in a vehicle that, while it may not have a throttle that seems quite as “infinite” as the Corvette’s, it still hauls the mail. You can’t argue with a 3.8-second 0-60 time and a top speed of 190 mph — except when it comes to applying the heat the millisecond you ask for it. The GTS’s 3.8-liter engine produces 324 lb-ft of torque at 5,760 horsepower, which is lower and later than the bigger engine in the ‘Vette, even though its horsepower is higher by 30. The result is a microscopically lower responsiveness. A few milliseconds in each turn can add up to a few seconds in each lap, and it grows over a full race. (But the Porsche weighs 200 pounds less, which means it shimmies through the turns just a bit more silkily than its competitors, potentially making up that time.)

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Porsche’s technology-packed flat six from the Carrera GTS.

Behind the wheel, the Porsche felt more precise and more tightly wound than the Corvette, with a distinctly higher engine note that, while not as formidable, still meant business. Another car to consider in the discussion is the new Subaru Impreza WRX, which squeezes an impressive 268 horsepower out of its turbocharged 2-liter, four-cylinder engine. That experience: brisk and fun, but lacking in visceral feedback from the engine. More performance-tuned versions of that car — including the WRX STi, which doesn’t yet have the same core engine as the newer WRX — produce more audible engine notes, and the next STi will likely be beastly when that upgrade does happen. But still, it won’t hold a candle to a V8, even though it’ll blow it away in the fuel-efficiency department.

An Uncertain, but Optimistic Future

All of these cars address different kinds of enthusiast drivers, and for enthusiasts of big engines, there’s fortunately less and less reason to rue their fate as some sort of technological dinosaur. The hybrid V8 in the Porsche 918 hypercar produces a combined 887 horsepower yet creates 22 MPG combined — and the hypercar triad that also includes the Ferrari LaFerrari and the McLaren P1 work similarly. Even in more down-to-earth models, currently sans hybrid help, the same innovation that makes six- and four-cylinder engines so proficient is also making V8’s more acceptable for the long term. “While the function of a hybrid power plant or turbochargers in smaller engines provides a very efficient powerful alternative, there will always be a home for a large-displacement V8, in either gas or turbo-diesel form,” Millen says. “It’s still true: there is no replacement for displacement.”

Lee from Chevrolet notes that, in particular, the development of direct injection improved engine-management algorithms and the resurgence of cylinder deactivation are two strategies allowing enthusiast drivers to have their cake and eat it, too. “It only takes 15 horsepower to keep a Corvette cruising down the highway, and because we’re able to shut off half the cylinders when the driver’s not using them — and in the future perhaps even six cylinders — we can keep fuel consumption very low. We’ll continue pushing all of this innovation as hard as we can.”

Still, as Millen adds at the last second, the writing is definitely on the wall — at least when it comes to racecars that don’t necessarily need to hit all consumer requirements in terms of sound, experience and range. “This year’s Pikes Peak racer that I drove is full electric,” he explains, referring to the famous annual Colorado hill-climb event. “With six small motors and a relatively small battery pack, the new car weighs 2,500 pounds, is four-wheel-drive, and makes 1,500 lb-ft of torque and 1,400 horsepower. It provides a driving experience like I have never felt before.”

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