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on 10
Mar
2016 |
All rights reserved.
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Cadillac has been
falling for decades – actually since its peak in the late 1950s. Those
remember that it was once the world standard for luxury cars must be
very old or already dead. In recent years, General Motors is keen to
revive Cadillac as a world-class luxury car brand, something truly
comparable to Mercedes and BMW without resorting to heavy discount or
fleet sales. The new ATS and CTS show some promising signs. Although
their sales numbers have been disappointing (perception takes time to
change), I believe sooner or later it will get the success it deserved
providing it keeps pushing relentlessly. In the latest round of “the
empire strikes back”, its battlefield is stretched to the range-topping
F-segment. The new luxury limousine is called CT6.
We have been missing large Cadillacs since the demise of STS and DTS
four years ago. Fortunately, Cadillac has not forgotten its roots. The
CT6 is part of a huge, $12 billion investment program under which 8
all-new vehicles will be introduced. They will adopt a new
nomenclature, too. Sedans will be called CT-plus-number, while SUVs
will be XT-plus-number, where the number denotes class positioning.
This means the ATS and CTS could be renamed to CT4 and CT5 respectively
in the future.
The CT6 is large, unquestionably. It measures 5184 mm from nose to tail
and 3109 mm in wheelbase, longer than a standard-wheelbase Mercedes
S-class or BMW 7-Series. However, it is incredibly lightweight. The
range starts at 1659 kg with a four-cylinder engine and RWD or 1781 kg
with V6 and AWD, considerably lighter than other cars in the class. No
wonder Cadillac describes it as the size of 7-Series and the weight of
5-Series. What makes the lightweight possible is an aluminum-intensive
multi-material construction. It consists of mostly aluminum and
high-strength steel, including 13 high-pressure cast aluminum parts
used in the lower structure. All body panels are aluminum. The
structure is fabricated by adhesives, rivets, laser welding and a newly
developed aluminum spot welding. Overall, 64 percent of the structure
(including skins) is made of aluminum. It saves 99 kg compared with an
equivalent structure made of high-strength steel.
The CT6 is the first application of GM's new rear-drive Omega platform.
Naturally, it is classier and more advanced than the Alpha platform
underpinning ATS and CTS. Its front suspension is a
double-wishbone-based multi-link setup, while the rear is a 5-link
arrangement. Both are constructed largely in aluminum to save unsprung
weight, while Magnetic Ride Control provides infinitely variable
damping. To make the large car agile to steer, it is served with active
rear-wheel steering (like BMW 7-Series). Cadillac claims it offer
class-leading ride and handling, something we should not ignore after
witnessing the accomplishment of ATS and CTS.
The base 4-cylinder model is rear-wheel drive, but V6 engines mate with
a new active on-demand AWD system. It employs a variable clutch and a
transfer case to distribute power to the front wheels. In Normal mode,
60 percent power goes to the rear axle. In Sport, this is increased to
70 percent. Winter mode splits 50/50 to enhance traction. As the AWD
system is designed to work permanently, its transfer case features 2
gears, one for low speed and one for high-speed cruising, so that fuel
economy is improved.
There are 3 engines. The entry-level choice is the familiar 2.0-liter
direct-injection 4-cylinder turbo, carried over from ATS and CTS and
makes 265 hp here. It is unusual for a large luxury sedan to employ a
4-banger, which is traditionally seen as disgraceful (Mercedes used
4-cylinder engine only on the hybrid S-class). Perhaps Cadillac wants
it to capture the lower end of the market segment. After all, the
lightweight chassis makes such a small engine acceptable.
More conventional choice is a pair of new generation V6s. LGW is a
3.6-liter naturally aspirated unit with direct injection and cylinder
deactivation. It produces 335 hp and 284 lbft of torque – the latter is
actually slightly less than the turbo four. LGX is a 3.0-liter
twin-turbo direct injection V6, again equipped with cylinder
deactivation to save fuel. It produces 404 hp and 400 lbft of torque,
saving the need for a V8 engine. However, rumors said a new 4.2-liter
twin-turbo V8 is being developed for the forthcoming Vsport model. All
3 engines work with GM's new 8-speed automatic transmission.
In terms of mechanicals, the CT6 seems to be competitive against the
best of the world. However, as a flagship luxury car, it underwhelms in
many subjective areas. One of them is styling. While the CTS-inspired
front-end design looks graceful enough, its side view is dull, and the
blocky trunk has no aesthetic to speak of. Moreover, it lacks the
elegant fine details that a top-notch luxury car needs. As a result,
the visual quality fails to match the likes of Mercedes or BMW.
Inside, the cabin design is equally disappointing. It looks busy and
lacks coherence. The woods, carbon-fiber trim and leather mix and match
arbitrarily without showing a clear design philosophy. Quality feel is
hampered by using too many plastic bits here and there. The TFT color
instrument is more attractive to look than conventional dials, of
course, but its graphics are plain and the numbers are overcrowded.
Most controls lack the slick touch and impeccable feel of those on
German limousines.
The CUE infotainment system is once again its single biggest flaw.
Although its touchscreen has been enlarged to 10.2-inch, the menus have
been simplified and a touchpad has been added on the transmission
tunnel as an alternative input, it is still frustrating to operate
while the car is moving. Why not simply use a tactile rotary control
knob like its German rivals?
Still, the cabin offers acres of room. The front seats are comfy. Rear
passengers are served with a 4-zone climate control, entertainment
screens as well as reclining, heated, cooled and massaging seats. This
large Cadillac will be sold globally – yes, for the first time perhaps
– but a lot of them are expected to serve Chinese customers who would
spend time only at the back seat.
However, those willing to take the driver seat will find pretty good
fun, especially on the base 2.0 Turbo model. Its nose is lighter, and
the whole car is light yet stiff. It steers faithfully and delivers
good road feel into your hands. Body roll is well checked by the
magnetic ride control suspension while ride quality is generally
smooth. The four-pot engine is surprisingly refined under the bonnet of
CT6, transmitting little sense of vibration and noise into the cabin.
It also pairs well with the 8-speed automatic to achieve a smooth and
linear power delivery. At speed, the Cadillac remains whispering quiet,
just as you would expect for a world-class limousine.
The V6 models are less remarkable. With a heavier nose and compulsory
4WD that complicates the steering feel, they are not as nimble or as
communicative as the 2.0 Turbo. The naturally aspirated 3.6 V6 needs to
work harder to deliver extra performance. The twin-turbo V6 is more
effortless to do so, but neither would you call it a sports saloon,
because it takes over 5 seconds to go from 0-60 mph. The V6s are
smoother, of course, but the transmission does not shift as precisely
when mate with them. 4-wheel steering regains some agility at slower
corners, but in faster bends it fails to tame the understeer.
As the first effort to re-enter the top luxury segment, Cadillac CT6
has quite a lot of areas to improve. Its styling shall be more elegant.
Its build quality and finish should be improved. Its infotainment
system should be overhauled. More power won't be wrong. Having said
that, the base 2.0T model with its crisped handling and bargain price
should find a unique space in the market segment.
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Verdict:  |
Published on 7
Feb 2020
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All rights reserved.
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CT6-V
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When
it made debut in 2018 Detroit auto show, no one knew it would be the
farewell model of CT6...
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By the time you have read
this overdue article, Cadillac CT6-V has already ceased production. In
fact, the entire CT6 line went out of production last month when GM
shut down
its Detroit-Hamtramck assembly plant. That is just less than 4 years
since the
car went on sale. It symbolizes the failure of Cadillac’s pursuit of
challenging German premium brands. GM seems to have already given
up this dream when it sacked Cadillac boss Johan de Nysschen in April
2018.
The CT6 was a substantial investment by GM. It introduced an all-new
multi-material chassis and new technologies like a variable AWD and
rear-wheel steering. As a result, the finished car offered a better
handling than its German counterparts. However, it was also flawed in
some crucial areas, such as dull design, a cheap interior and
underpowered engines. In addition to an inferior brand image, it turned
out to be a commercial failure. Cadillac sold just over 10,000 units of
CT6 in
North America even in its peak year. Sales in China is a little better,
but that is just because it is sold at half the price of its rivals. No
wonder GM’s top management ran
out of patience and decided to write off the investment early.
The development plan of CT6-V is no less ambitious, because it
introduces an all-new quad-cam twin-turbo V8 called “Blackwing”. That
is GM’s first DOHC V8 since the demise of Northstar V8. In
specifications, it closely matches its German rivals: 4192 c.c.,
all-aluminum construction, hot-Vee architecture (turbos sit inside the
V-valley for short piping hence less turbo lag), a pair of twin-scroll
turbochargers running a maximum boost pressure of 1.4 bar, 9.8:1
compression ratio, direct fuel injection, “Active Fuel Management”
cylinder deactivation technology (one of the few technologies pioneered
by GM), dual-VVT and forged steel crankshaft and con-rods. The
state-of-the-art engine was designed purely for the applications of
Cadillac, though now GM might wonder whether to scrap it or adapt it
for the go-faster version of Corvette.
On the CT6-V, the Blackwing produces 550 horsepower. It is not quite as
powerful
as Mercedes-AMG S63 or BMW M760Li, both of which exceed 600. That is
why Nysschen originally planned to badge it Vsport instead of V.
Somehow, when GM sacked Nysschen and cut back the investment on
Cadillac’s sedan and performance car lineup, it simply rescaled the V
sub-brand to a notch below AMG and M, so the new V is more like BMW’s M
Performance models. As for torque output, the Blackwing V8 is very
competitive at 640 lbft, but its torque band is not quite as wide as
its rivals. The peak torque is available at a rather high 3400 rpm, and
you don’t get 90 percent of which until 2000 rpm.
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“Blackwing”
is GM’s first DOHC V8 since the demise of Northstar V8.
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On
the road, the CT6-V is by no means slow. Aided by standard AWD, it is
good for 0-60 in 3.8
seconds and 100 mph in just over 9 seconds. However, maybe because of
the smooth power delivery, or the slight hesitation before the turbos
spool up, or simply because its peak torque doesn’t arrive as urgently,
it never makes you sweat. The induction noise and exhaust note are
rather subdued, lacking the excitement of AMG motors, explaining why it
should have been badged Vsport. In isolation, this is a good engine by
the standard of GM. If they tell us it was a turbocharged version of
LT2
small-block, we would applause. Unfortunately, when you compare with
the rivalling quad-cam hot-Vee motors of Mercedes, BMW, Audi and
Porsche, you will be disappointed by its narrow power band. Not only
its peak power is produced at 5000 rpm, but it will cut out fuel at
6000 rpm. When the V8 switches to 4-cylinder mode at lighter loads,
there is noticeable vibration at the transition point. Not as powerful,
not as eager and not as refined as rivals, the Blackwing has room for
improvement.
The V8 is hooked up to a new 10-speed automatic co-developed with Ford.
Considering the transmission is shared with some Ford trucks, it works
remarkably well on a luxury car. Gearshift is smooth and generally well
timed, although 10 ratios might be too many for an uninterrupted
acceleration. Drive harder or use paddle shift, however, you will
find gearshifts slower and less refined than the best ZF or Mercedes
trannies.
Changes to the exterior is subtle, Q-car like. Apart from a mesh
grille, some revised intakes and a tiny boot spoiler, little
distinguish it from lesser CT6. The chassis is similar. As mentioned,
this car should have been a Vsport, so it is no surprise to see
modifications are limited to springs, anti-roll bars, retuned software
of Magnetic Ride Control dampers and steering etc. Oh yes, a mechanical
LSD is added to the rear axle and Brembo brakes are adopted. That said,
it carries over the rear-wheel steering and AWD system from the CT6.
The latter still splits torque by 40:60 front to rear normally, but if
you switch to Sport and Track mode, it will change to 20:80 and 5:95,
respectively.
In truth, the CT6-V handles its mass better than the limousines coming
from AMG or M. Its narrower tires might afford less grip, but on public
roads this doesn’t matter. The point is, with 4WS and an inherently
better balanced chassis, it feels smaller than its rivals. The steering
is lighter and a touch more communicative. Meanwhile, the ride quality
is still very high, certainly smoother than BMW M760Li. In terms of
ride and handling balance, Magnetic Ride Control seems to have an upper
hand over its rivals with air suspensions. The only obvious weakness of
its chassis is braking. While the Brembo brakes are strong enough, the
electric servo is overboosted, resulting in a spongy feel.
Inside, the CT6-V still suffers from some cheap materials, unappealing
fit-and-finish and second-class CUE infotainment system.
Disappointingly, the seats are the same as standard car, lacking
lateral support to deal with increased performance.
Overall speaking, as a farewell model of the CT6 line, the V is not
bad. It would have been better to call it Vsport to reflect its true
market positioning and performance level. Although it is not going to
be a classic, it is still sad to see the brand-new Blackwing V8 ended
in this way. Had it been given sufficient fine tuning and continuous
development,
it certainly has potential to be a world-class engine. Only about 600
Blackwing-powered CT6 has been built until its extinction, 450 of which
were the CT6-V, while the remaining were CT6 Platinum, whose engine
detuned to 500hp and chassis lacked the V upgrades.
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