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GM Unveils All New 450 hp Small Block LT1 V8 for 2014 Corvette
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Features and Highlights
All-aluminum block and oil pan: The Gen 5 block was developed
with math-based tools and data acquired in GM’s racing programs,
providing a light, rigid foundation for an impressively smooth engine.
Its deep-skirt design helps maximize strength and minimize vibration. As
with the Gen 3 and Gen 4 Small Blocks, the bulkheads accommodate
six-bolt, cross-bolted main-bearing caps that limit crank flex and
stiffen the engine’s structure. A structural aluminum oil pan further
stiffens the powertrain.
The block features nodular iron main bearing caps, which represent a
significant upgrade over more conventional powdered metal bearing caps.
They are stronger and can better absorb vibrations and other harmonics
to help produce smoother, quieter performance.
Compared to the Gen 4 engine, the Gen 5’s cylinder block casting is
all-new, but based on the same basic architecture. It was refined and
modified to accommodate the mounting of the engine-driven direct
injection high-pressure fuel pump. It also incorporates new engine mount
attachments, new knock sensor locations, improved sealing and oil-spray
Advanced oiling system, with available dry-sump system: The
LT1 oiling system including oil-spray piston cooling was also
optimized for improved performance. It is driven by a new,
variable-displacement oil pump that enables more efficient oil delivery,
per the engine’s operating conditions. Its dual-pressure control
enables operation at a very efficient oil pressure at lower rpm
coordinated with AFM and delivers higher pressure at higher engine
speeds to provide a more robust lube system for aggressive engine
Standard oil-spray piston cooling sprays the underside of each piston
and the surrounding cylinder wall with an extra layer of cooling oil,
via small jets located at the bottom of the cylinders. For optimal
efficiency, the oil jets are used only when they are needed the most: at
start-up, giving the cylinders extra lubrication that reduces noise,
and at higher engine speeds, when the engine load demands, for extra
cooling and greater durability.
An available dry-sump oiling system promotes exceptional lubrication
system performance during aggressive driving maneuvers and high
cornering loads. It includes two stages: a pressure stage and a scavenge
stage. The pressure stage includes the new, dual-pressure-control and
variable-displacement vane pump.
Dexos semi-synthetic motor oil, with a 5W30 specification, helps reduce friction to further enhance the LT1’s efficiency.
New, tri-lobe camshaft: Compared to the Gen 4 Small Block, the
camshaft remains in the same position relative to the crankshaft and is
used with a new rear cam bearing, but it features an all-new “tri-lobe”
designed lobe which exclusively drives the engine-mounted direct
injection high-pressure fuel pump, which powers the direct-injection
combustion system. The cam’s specifications include 14mm/13.3mm
(0.551/0.524-inch) intake/exhaust lift, 200/207-crank angle degrees
intake/exhaust duration at 0.050-inch tappet lift and a 116.5-degree cam
angle lobe separation.
New, cam-driven fuel pump: The direct injection system
features a very-high-pressure fuel pump, which delivers up to 15Mpa (150
bar). The high-pressure, engine-driven fuel pump is fed by a
conventional fuel-tank-mounted pump. The direct injection pump is
mounted in the “valley” between cylinder heads beneath the intake
manifold and is driven by the camshaft at the rear of the engine. This
location ensures any noise generated by the pump is muffled by the
intake manifold and other insulation in the valley.
PCV-integrated rocker covers: One of the most distinctive
features of the new engine is its domed rocker covers, which house the,
patent-pending, integrated positive crankcase ventilation (PCV) system
that enhances oil economy and oil life, while reducing oil consumption
and contributing to low emissions. The rocker covers also hold the
direct-mount ignition coils for the coil-near-plug ignition system.
Between the individual coil packs, the domed sections of the covers
contain baffles that separate oil and air from the crankcase gases
about three times the oil/air separation capability of previous engines.
Intake manifold and throttle body assembly: The LT1’s intake
manifold features a “runners in a box” design, wherein individual
runners inside the manifold feed a plenum box that allows for excellent,
high-efficiency airflow packaged beneath the car’s low hood line.
Acoustic foam is sandwiched between the outside top of the intake
manifold and an additional acoustic shell to reduce radiated engine
noise, as well as fuel pump noise.
The manifold is paired with an electronically controlled throttle,
featuring an 87mm bore diameter and a “contactless” throttle position
sensor design that is more durable and enables greater control.
Four-into-one exhaust manifolds: The LT-1 uses a cast version
of the “four-into-one” short-header exhaust manifold design used on the
Gen 4 LS7 engine. The cast header passages enable consistent exhaust
flow into the “wide mouth” collector at the converter.
Cooling system, humidity sensor and more: Additional features and technologies of the Gen 5 Small Block include:
A revised cooling system with an offset water pump and thermostat for more efficient performance;
Air induction humidity sensor ensures optimal combustion efficiency, regardless of the surrounding air’s humidity;
58X ignition system with individual ignition coil modules and iridium-tip spark plugs;
All-new “E92” engine controller.
General Motors says its investment in the Gen 5 Small Block will create or
retain more than 1,600 jobs in five North American plants, including
Tonawanda, New York, which recently received upgrades to support its
For more information about Chevrolet, visit www.chevrolet.com. Also, check out the video that animates and explains how all of the new technology works together.
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