Finger follower valve train: instead of
opening valves directly with cam lobes pressing bucket tappets, the finger
follower design does that job with pivoting beams. Finger followers use static
hydraulic lash adjusters to diminish the mass of valve train components in
motion. The new GT3 design provides a large contact area between each cam lobe
and its follower.
Porsche's near-comical expansion of the 911
family there were more than 20 derivatives of the last-gen car makes it all but
certain to capture every last potential buyer. It also guarantees constant
attention over the 911's life span as the inevitable waves of redesigned
variants roll in one after the other. We've already seen the convertible and
four-wheel-drive models drawn from the 991 gene pool. Now it's time for a more
sporting version: the GT3. Introduced as a 2010 model, the last GT3 was
powerful, fast, and among the most satisfying cars extant. Porsche's challenge
is to improve on it while incorporating the new generation's longer wheelbase
and wider tracks. Here's how Stuttgart brings the ruckus
The
new GT3 design provides a large contact area between each cam lobe and its
follower.
Steering
As with the new 911, the GT3 gets
electrically assisted rack and pin ion steering specifically calibrated for
this application. The last GT3 had perhaps the sweetest steering feel we’ve
experienced, so we will be looking closely at the execution of this critical
control. Perhaps even more signify cant is the addition of rear-wheel steering
in which two actuators steer the rear wheels up to i.5 degrees. Below 31 mph,
the rear wheels steer opposite the fronts to improve maneuverability and
provide quicker directional changes. Above 5o, they steer in sync with the
fronts for increased high-speed stability, making the GT3 feel as if its
wheelbase were 20 inches longer at speed.
Aerodynamics
As usual, the GT3 is distinguished by
larger front air intakes to provide the cooling necessary for extended track
use-Porsche claims that 8o percent of GT3s spend time at the racetrack. There's
also a prominent lip spoiler, an adjustable rear wing, and a composite molding
that incorporates the engine air intakes. A diffuser supplements the down force
produced by the new wing.
A
diffuser supplements the down force produced by the new wing.
Power
The previous GT3 was the only 911 that
didn't get direct fuel injection, yet it still managed to extract 435 horse-
power and 317 pound-feet of torque from its 3.8 liters. The 2014 version
finally gets direct injection, plus a whole lot more to bump output to 475
ponies and 325 pound-feet from the same displacement.
Based on the latest Carrera S engine and
sharing its bore and stroke, the new GT3 engine has forged pistons and titanium
rods, hollow valve stems, new cylinder heads with finger-follower valve
actuation, and a more elaborate dry sump lubrication system with seven oil
pickups. The engine is some 55 pounds lighter than the old one, but more
robust. Its power peak jumps from 7600 rpm to 8250 and its redline from 8400 to
9000. Credit a freer-flowing intake system, camshafts with long duration and
lots of lift, and a 12.9:1 compression ratio. The 3.8's 125 horsepower per
liter ties the Ferrari 458's 4.5-liter V-8 for the highest specific output for
a naturally aspirated engine in production. Porsche claims a top speed of 196
mph. Based on the 3.6-second zero-to-6o time of the last GT3 we tested and the
addition of a dual-clutch auto with launch control, we'd expect this one to
manage the job in 3.2 seconds and to cover the quarter-mile in about 11.6
seconds.
The
2014 version finally gets direct injection, plus a whole lot more to bump output
to 475 ponies and 325 pound-feet from the same displacement.
Transmission
Unlike the last GT3, which came exclusively
with a close-ratio six-speed manual, the new model is only offered with
Porsche's seven-speed dual-clutch automatic. As you'd expect, the gears are
more closely spaced than the regular Carrera PDK's with an overall ratio spread
of 4.5, down from 6.3. Coupled with a 3.97:1 final-drive ratio instead of the
Carrera's 3.44, this arrangement yields 57-percent higher revs in seventh gear.
That will help keep the screaming 3.8 six within striking distance of its
6250-rpm torque peak, as well as its nine-grand redline. Paddle shifters
provide the driver full manual control, but if you prefer to let the car shift
itself, it will. It might be slightly tamer that way, but your mother still
won't approve. The only automatic modes are "sport" and
"racetrack"
Unlike
the last GT3, which came exclusively with a close-ratio six-speed manual, the
new model is only offered with Porsche's seven-speed dual-clutch automatic.
Chassis
The new GT3's suspension is based on the
standard Carrera setup, but with stiffer springs and firmer shock calibrations
in its standard PASM (Porsche Active Suspension Management) system. The GT3's
body rides 1.2 inches closer to the pavement than a standard Carrera's. Several
racy touches are carried over from the last model, including two-piece wheel
hub and brake carriers, as well as center lock wheels. The front wheels are now
9 x 20 inches in size, up half an inch in width and one inch in diameter. The
rears remain 12 inches wide, but despite the move to a 20-inch diameter, wheel
and tire assemblies are slightly lighter than before. Aluminum front struts,
lighter coil springs, and various other components shave pounds from both
sprung and un-sprung weight.
