Content provided by Tom Murphy / WardsAuto
The last time a 4-cylinder was available in a Porsche sports car in the U.S. was 1991, the year production ended of the 944, a 2+2 coupe and convertible.
The inline 4-cyl. came in displacements of 2.5L, 2.7L and 3.0L, and certain versions were naturally aspirated. Output ranged from 143 hp at launch in
1982 to 247 hp in the 944 Turbo S as the model run ended. The 3.0L was the largest 4-cyl. production engine of its time, and this engine family was part
of the industry’s steady migration toward dual overhead cams and four valves per cylinder.
So it’s been 25 years in the making, this return of 4-cyl. power to Porsche’s U.S. lineup. The ’17 718 Boxster convertible and 718 Cayman coupe arrive
with two turbocharged 4-cyl. boxer engines to choose from: a base 2.0L rated at 300 hp and 280 lb.-ft. (380 Nm) of torque beginning at 1,950 rpm and the
2.5L in “S” models churning out 350 hp and 309 lb.-ft. (419 Nm) at 1,900 rpm.
It’s still too early to detect a trend among buyers, but historically Porsche has sold more base Boxsters and Cayman S models. Until now, the cars only had
6-cyl. boxer engines. The new 718 Boxster went on sale in the U.S. in June, and the 718 Cayman arrives in November.
The new engines represent the first time Porsche, with a rich legacy of horizontally opposed piston engines, has developed one that combines
turbocharging and only four cylinders.
The 2.0L and 2.5L engines share a 7,500-rpm redline, 9.5:1 compression ratio, direct fuel injection, four valves per cylinder, water-to-air intercooling, an
on-demand water pump, integrated dry sump lubrication, demand-controlled oil pump and VarioCam Plus valve stroke adjustment for intake and
The single turbochargers, supplied by BorgWarner, are unique to each engine. The 2.0L with a conventional wastegate benefits from 20.3 psi (1.4 bar) of
maximum boost, while the 2.5L employs a variable-turbine geometry unit that produces 14.5 psi (1 bar) of thrust. This turbocharger is similar to the one
previously used in the Porsche 911 Turbo.
The 2.0L turbo-4 boxer will be included in the 2017 Wards 10 Best Engines competition, thanks to starting base prices of $53,900 for the 718 Cayman and
$56,000 for 718 Boxster in the United States.
However, the 2.5L is ineligible for the competition, exceeding this year’s $62,000 base price. Starting prices are $66,300 for the Cayman S and $68,400 for
the Boxster S again in the United States.
Porsche engineered both the 4-cyl. engines about the same time as the 370-hp 3.0L twin-turbo flat-6 in the 911 (which began production in Germany in
“All three are based on the same technology, so we have a lot of synergy between those engines,” says Markus Baumann, manager of boxer engines at
For instance, the 2.0L and 3.0L share the same identical connecting rods, accessory drive, timing belt, connecting rods, seals, bearings, vacuum pump,
camshaft adjusters, valvetrain components, fuel injectors and cylinder liners plasma-coated with iron through a rotating single-wire process.
The aluminum blocks and heads are made on one assembly line by one supplier. The automaker tried to use plastic for the oil pan but ultimately needed
aluminum because of thermal challenges.
Baumann calls the overall strategy with the new engines “turbo rightsizing” instead of downsizing.
“We get 300 hp, and these engines are good at low revs and at high revs,” Baumann tells journalists here during the media launch of the 2.0L and 2.5L
powerplants in the new mid-engine 2-seaters.