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AUTOMOTIVE ENGINEERING 6 November 2015
POWERTRAIN
Porsche unveils new downsized, boosted 3.0-L boxer six
The words “Porsche” and “turbo” have
been synonymous with ultimate high per-
formance since 1972, when the automaker
first used boosted engines in the mighty
917/10 Can-Am racecars. For 2016MY, the
company is introducing all-new turbo-
charged 3.0-L flat-six engines for the 911
Carrera and Carrera S road cars, replacing
naturally aspirated (NA) 3.4-L and 3.8-L
units. The 911 that carries the specific
“Turbo” designation, however, will con-
tinue to use a 3.8-L engine.
The 3.0-L Carreras were unveiled at the
2015 Frankfurt Motor Show. The down-
sized-and-boosted “boxer” brings new
levels of efficiency and added power; the
Carrera gets an extra 15 kW (20 hp) tak-
ing peak output to 272 kW (365 hp). The
Carrera S produces 309 kW (414 hp), also
a 15-kW improvement. The new engines
use two BorgWarner turbos, one per cyl-
inder bank.
The S version of the 3.0 L features
modified turbine compressors, a specific
exhaust system and tuned engine man-
agement. Boost pressure is 0.9 bar (13
psi) in the Carrera and 1.1 bar (16 psi) in
the Carrera S. The new engine also pro-
duces more peak torque—an added 60
N·m (44 lb·ft), delivered from 1700 to
5000 rpm, to provide 450 N·m and 500
N·m (331 and 368 lb·ft), respectively. Both
variants are rev-limited to 7500 rpm.
Performance of both the Carrera and
Carrera S is slightly improved, the S fit-
ted with PDK (dual clutch) and Sport
Chrono Package achieving a claimed
0-100 km/h in 3.9 s, and top speed of
307 km/h (190 mph). But fuel consump-
tion and emissions are markedly better;
the S with PDK achieves a combined fig-
ure of 7.7 L/100 km, an improvement of
1.0 L/100 km. Claimed CO
2
emissions are
169 g/km for the regular Carrera, 174 g/
km for the Carrera S.
According to Porsche technology
spokesperson Nick Perry, the new 911 mod-
els will not be badged “Turbo.” He also
explained that the very high performance
911 GT variants were a “separate topic”
with regard to the application of turbo-
charging: “The current Turbo will continue
to be described as that; the model offers a
different image and attributes to those of
the Carrera. We have turbochargers in the
Panamera, Cayenne and Macan, but there,
too, we use the designation Turbo for top
of the range versions.”
Inside the new boxer
Track-to-road technology transfer is a
major element of Porsche’s engineering
creed but its racing 911s have NA engines
to meet regulations. “The NA GTRS 4.0-L
engine will continue to power our 911s in
the motorsport realm,” Perry explained.
“But for road cars there is a multitude of
criteria to meet, which is why we are in-
troducing the new engine.”
He described the new engine as a
“step-change”—the 3.0-L being all-new
and not a derivative of the 3.4 and 3.8
engines. The move is similar to when
Porsche went to liquid cooling (1998MY)
to reduce drive-by noise, improve perfor-
mance and efficiency, running the engines
hotter and achieving better combustion.
Another step-change came in 2008 with
the introduction of direct fuel injection.
Porsche is making no formal comment
about the new 3.0-L turbo family forming
the basis of engines for other models
ranges including the Boxster and Cayman,
but siblings can be expected.
The use of forced induction has re-
quired a new engine airflow system for
combustion and intercooling at the rear of
the Carreras. The engine gets its combus-
tion air centrally in front of the rear spoil-
er. From two lateral ports on the air filter
box, the airflow reaches two induction
channels to the lower-mounted turbo-
chargers. The compressed and heated air
then flows through two intercoolers lo-
cated laterally behind the wheel arches
and onwards to the engine’s induction
manifold via the throttle plate. Two other
ducts guide the air for cooling the heated
combustion air (also from the air screen
in the rear lid) to the intercoolers.
The 3.0-L’s injectors are located in the
The latest Porsche boxer six features plasma-coated cylinder bores, lighter
crankcases, an engineered-plastic oil pan, and direct injection that operates at
up to 250-bar system pressure. The water pump is now clutched and can remain
disengaged at low coolant temperatures, for reduced friction.
Semi-ghosted view of the 2016 Carrera shows engine air-intake and
exhaust gas paths, along with intercooler location. The all-new 3.0-L
boxer six delivers 42% more peak power than the original 1974 Turbo
of the same displacement, with significantly higher fuel efficiency.
TECHNOLOGY REPORT