That subtle background noise you hear isn't just the ticking of four cylinders where six formerly lived. It's the gnashing of teeth over the fact that Porsche downsized cylinder count and piston displacement to a mere 2.5 liters for the top, S edition of the 2017 718 Boxster. Our anxiety centers on the move by Porsche-along with practically every other auto manufacturer-from natural aspiration to smaller, theoretically more efficient, boosted induction. In case you've been napping, turbocharging is how makers maintain performance while diminishing the amount of fuel consumed and the CO2 spewing from their tailpipes.
Turbos, Then and Now
This is hardly Porsche's first trip through turbo valley. Fans of the brand still revere the legendary 911 Turbo bestowed upon wide-eyed enthusiasts 41 years ago. What that rear-engined bundle of turbo lag lacked in general drivability, it more than made up in excitement when the boost kicked in. A few fenders bent in those early days combined with countless turbocharging lessons learned over the years culminate in what is today a full family of twin-turbo 911 models, plus single-turbo 718 Boxsters and Caymans that arrived at dealers this summer. To celebrate the occasion, Porsche revived one of its most illustrious model codes for the fourth-generation Boxster/Cayman. Throughout the late 1950s and early '60s, the Rennsport department's endurance racers, hill-climbers, and Formula 1 and 2 single-seaters all were 718s.
Turbocharging is one of the 20th century's most significant engine advancements. Swiss engineer Alfred Buchi earned the seminal patent in 1905; in 1918, GE's Sanford Moss demonstrated how efficiently this device could replace the power lost to altitude at Pikes Peak. By World War II, turbo tech was one of America's most significant strategic assets. Chevrolet and Oldsmobile introduced the first turbocharged cars in 1962.
Operational theory hasn't changed. Energy normally dumped to the atmosphere out the exhaust pipe instead spins a turbine wheel connected by shaft to a centrifugal compressor. (Think two pinwheels attached to one spindle.) The compressor in turn boosts the pressure and density of the air delivered to the combustion chambers, significantly raising power output. A turbo is the ultimate energy recycler.
Porsche adds a few turbo tricks. The Boxster S has small pivoting vanes that direct exhaust flow toward the turbine wheel in an optimum manner, diminishing lag at low rpm and easing restriction at high rpm. To keep from stalling the compressor when the throttle is lifted, Porsche temporarily halts fuel delivery, leaving the throttle open, so boost is available when the driver gets back on the gas. Intake and exhaust valves both have variable timing and lift for improved efficiency; auto stop/start is now standard. Flow through the coolant and lubrication pumps varies according to demand. To give the new turbo fours an aggressive bark, there's a valve in the optional Sport Exhaust that opens at 3500 rpm to bypass part of the muffler. Push that button while idling, though, and the additional sound is both a letdown and out of character, more Subaru WRX than Porsche.
In addition to hiking both peak power and torque (to 350 horsepower at 6500 rpm and 309 lb-ft at 1900 rpm), the S engine's turbo fills in the 2500-to-4500-rpm valley in the previous 3.4-liter naturally aspirated engine's torque curve. The new torque plot is dead flat from 1900 to 4500 rpm, mimicking an electric motor's response when you dip into the throttle. That means you no longer have to drop a gear or wait for the tach needle to twirl to execute a quick pass.
This new torque bounty did prove frustrating at the track. Our acceleration-test skills were challenged by the Boxster S's lack of launch control, superb traction, and 4500-rpm limit prior to clutch engagement. Coaxing more than a quick chirp from the rear wheels and keeping the tach needle on the fruitful side of the dial was impossible. That's a long way of saying the new turbo-four engine is susceptible to bogging. We clocked the run to 60 mph in 4.3 seconds, just a tenth of a second quicker than the slightly lighter Boxster S we tested four years ago. The better news is we beat that normally aspirated predecessor by 0.3 second and 2 mph in the quarter-mile, running 12.6 seconds at 113 mph. Top-gear acceleration was slightly slower from 30 to 50 mph but a satisfying 0.7 second quicker from 50 to 70 mph.
Of course life is more than stats. Tickle the throttle with 2000 or more rpm on the tach and the boost gauge comes to life while your lower back receives a satisfying shove. This is not to say you'll annihilate Corvettes from stoplights, but, like every Boxster for the past two decades, there are compensating virtues. One is impeccable braking with superb pedal feel, effort, and modulation. We measured a 144-foot, 70-to-zero-mph stopping distance, three feet shorter than the previous Boxster S and five feet better than a Jaguar F-type S.
Cornering addicts who settle into the Boxster S's cockpit should plan on being consistently late for dinner. To improve response, Porsche bolted in the 911 Turbo's rack-and-pinion steering gear, quickening the on-center ratio by 10 percent. Hints of actual road feel work their way to the wheel, a rarity for electrically assisted steering. There's just enough understeer at the 1.04-g cornering limit to let you know you're not tethered to the road with steel cables. Pitch and roll motions are verboten thanks to shrewd suspension calibrations and adaptive dampers (which cost $2070 extra). For daily haring around combined with supreme track-day competence, few sports cars at any price top a Boxster S. Add to that a ride that never beats you up.
As convertibles go, this is one of the best. The top disappears and reappears in 10 seconds at speeds up to 43 mph at the flick of a switch and serves as its own boot when folded. There's so little cockpit turbulence you can bask in the sun at 100 mph. Some of us love the cupholders that swing out of a cleverly covered dash slot; others vote no on that execution. One missing convenience is a handy place to park your smartphone. However, there are decent storage areas in the glovebox, center console, and door pockets, plus a reasonable amount of luggage space divided between the trunks at each end of the car. If only Porsche had contrived some way to actually see the new turbo-four engine short of lifting the car on a hoist.
The odd thing about this third-generation Boxster S is that dropping two cylinders saved no weight and the presumed goal of higher EPA ratings also wasn't realized. The car tested here is 52 pounds heavier than the aforementioned 2013 model, largely the result of adding larger brakes and more sophisticated dampers. EPA city ratings are unchanged at 20 mpg with the six-speed manual and 21 mpg with the PDK automatic, but there's a 2-mpg decline in highway mileage to 26 mpg for the stick and 28 for the PDK. We recorded 18 mpg overall-versus 19 for the previous Boxster S-and a commendable 30 mpg while cruising at 75 mph.
A wealth (literally) of options in our test example rocketed this Boxster S's price from $69,450 to a frightful $94,310. (For reference, the 911, with two more cylinders and a second turbo, starts at $90,450.) The list of 18 options included stuff that's almost essential-the $2070 sport suspension, $1580 20-inch wheels, and a $1320 torque-vectoring differential-but there were expensive upgrades that the frugal could live quite happily without. Leather-trimmed heated and cooled 18-way memory seats, for example, added $4725 to the tab.
The Sport Chrono package at first glance seems like a very expensive ($1920) stopwatch perched atop the dash. Closer examination reveals this is the hard-core enthusiast's bonus box. There are analog and digital displays controlled by a column stalk capable of logging hot laps, track position, and whether you're gaining or losing speed. The more useful tool is a twist knob on the steering wheel borrowed straight from the 918 Spyder that lets you switch among four drive modes. This tunes the operation of a dozen or so systems to tailor the car's dynamics to the driver's mood. You can tighten up the variable powertrain mounts, lift the rear spoiler to its airfoil position, disable auto stop/start, and activate exhaust overrun pops and snorts. Some of the noise is piped through a speaker, but the Sport and Sport Plus drive modes rid the soundtrack of any hint of a Volkswagen Beetle. That's not to say it brings the return of the previous flat-six soundtrack, which could outperform the lead tenor at the Metropolitan Opera. The new notes fall more under the heading of karaoke howling, and the sound is enough of a loss to the overall experience that it would send us to the used-car listings in search of a previous-generation Boxster with the singing six instead.
Still, aside from the sound, consider the 718 Boxster S the antidote to autonomous driving. Steering that speaks with the road, a shifter that connects driver and driveline, and the raucous throb of gasoline and air converted to forward momentum might soon be obsolete if the soothsayers are to be believed. To that we say enjoy the magic while it lasts.
VEHICLE TYPE: mid-engine, rear-wheel-drive, 2-passenger, 2-door convertible
PRICE AS TESTED: $94,310 (base price: $65,850)
ENGINE TYPE: turbocharged and intercooled DOHC 16-valve flat-4, aluminum block and heads, direct fuel injection
- 152 cu in, 2497 cc
- Power: 350 hp @ 6500 rpm
- Torque: 309 lb-ft @ 1900 rpm
- 6-speed manual
- Wheelbase: 97.4 in
- Length: 172.4 in
- Width: 70.9 in Height: 50.4 in
- Cargo volume (front/rear): 5/4 cu ft
- Curb weight: 3122 lb
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