Page 12 - Victory Driven: Cadillac V-Series sample pages

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After almost two decades of development, the Northstar V8 SC
had come to fruition. Its high-tech construction, performance and
exclusivity made it the perfect match for the V machines it powered.
HOT ROD ROADSTER: 2006 XLR-V
In the 2006 XLR-V, the DOHC Northstar V8 SC displaced 4.4 liters
and featured continuously variable valve timing (VVT). Initially, the
Northstar V8 SC followed the Evoq’s engine parameters with its
Fine Books © Dalton Watson Fi 4.2-liter displacement. However, GMPD’s increased horsepower
and torque requirements led to the larger 4.4-liter bore. This also
necessitated Eaton’s development of longer blower rotors and their
housing. The smaller bore size, 91 mm rather than the NA 4.6L
Northstar 93 mm, made for a more rigid block, a definite benefit for
the more powerful engine. With a blower-friendly 9.0:1 compression
and 12 psi of maximum boost, the XLR-V put down 443 hp/414 lb-ft.
Although completely based on the RWD Northstar V8, the (LC3)
Northstar V8 SC incorporated many new, specific features for its
supercharged duties. These included a sand-cast aluminum upper
block/cylinder case (rather than die-cast) and a closed deck design
for greater strength to handle the increased power.
Primary to its forced-induced operation, the LC3 employed features
© Dalton Watson Fine Books © Dalton Watson Fine Books for increased strength and cooling. They included:
Revised coolant paths around the bores for greater flow
Piston oil-coolers cast into the oil galley. These jet
nozzles provided constant lubrication from the crankcase,
strategically spraying the underside of each piston during
its downward stroke
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A heavy-duty 9.0:1 piston design and heat-treated
connecting rods that were utilized to withstand and
optimize the higher level of supercharged combustion
A forged steel crankshaft with rolled fillets was carried over
from the higher-compression, natural aspirated Northstar V8
© Dalton Watson Fine Books © Dalton Watson Fine Books The LC3’s aluminum cylinder heads were unique in that they were
designed to seamlessly integrate with the supercharged induction
system. The features that differentiated the LC3’s cylinder heads
from the NA Northstar V8 included:
A modified combustion chamber, with a deeper exhaust
port septum
The exhaust ports were polished using a patented process
Continuously variable valve timing (CVVT) was carried over from
called Extrude-Hone which created a smooth, completely
the NA Northstar V8. For the LC3, the engine control computer was
friction-free passage for greater exhaust flow from the head
specifically recalibrated, optimizing the system for supercharged
performance.
VELOCITY // ThE V1 CTS-V, XLR-V aND STS-V (2004-2009) CADILLAC’S V-SERIES Both the intake and exhaust valve seats were copper-
infiltrated for better heat transfer under the SC’s greater
thermal loads. The NA Northstar V8 had this treatment only
But what gives the LC3 Northstar V8 SC its name and fame was
on the exhaust side
a patented integral design, helical roots-type, high twist rotor,
alton Watson Fine Books © Dalton Watson positive-displacement intercooled supercharger. The blower-
The LC3’s cylinder head deck height was also increased
intercooler unit was cleverly designed to be part of a greater
and multi-layer steel head gaskets were installed to ensure
induction module that also included the intake manifold.
proper sealing
It was very important for this supercharged induction system to be as
The LC3’s roller chain dual overhead camshaft drive was the same
low-profile as possible. Although eventually applied to subsequent V
as used on the NA Northstar V8 but with necessary upgrades for
models as a functional necessity and aesthetic advantage, Cadillac
its supercharged application. The flame-hardened, cast nodular
did not want to modify the XLR’s hood, fearing this would further
iron camshafts featured revised profiles. This increased intake and
obstruct the already hunkered-down view through the windshield.
exhaust valve duration greatly improved the blown motor’s ability
Even with lessons learned from the Evoq, this still represented the
to breathe.
ine Books ©