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The lighter-weight aluminum alloy
V-6 is more powerful than its predecessor partly because of its
new cylinder head design, which has a revised intake port design
that enhances airflow to the combustion chambers.
Larger-diameter intake valves in the heads and new,
longer-duration intake camshafts help provide the engine’s boost
in horsepower.
By using larger valves and holding
them open longer, more air is pulled into the combustion
chamber, for more powerful combustion. Often, the tradeoff for
greater power is greater fuel consumption, but engineers
optimized the fuel system for the engine’s performance
parameters.
“As a result, there is more power
without sacrificing fuel economy,” Sutter said. “The
more-efficient combustion also means reduced emissions.”
The engine retains direct fuel
injection, enabling greater combustion efficiency, but uses a
new fuel pump and a new, isolated fuel rail. The new fuel pump
is quieter, while the isolated fuel rail further reduces fuel
system noise to help maintain LaCrosse’s quiet-tuned operation.
Direct injection also delivers reduced emissions, particularly
on cold starts, where hydrocarbon emissions are cut by about 25
percent.
The new V-6 uses several
lighter-weight components that help maintain LaCrosse’s fuel
efficiency while boosting its horsepower. The new integrated
cylinder head/exhaust manifold design saves about 13 pounds
compared to the cylinder heads and manifolds of the previous
engine, while the new composite intake manifold saves about 5.5
pounds. Additionally, a light-weight structural front cover and
lightweight, high-strength connecting rods bring the total
weight savings to 20.5 pounds, improving fuel efficiency and
enhancing the feeling of driving balance.
“Thanks to increased use of
lightweight components and other enhancements, the new 3.6L V-6
offers 2012 LaCrosse buyers improved acceleration with no hit to
fuel efficiency,” said Doug Osterhoff, LaCrosse product
marketing manager. “This new engine is an attractive option on
the car that’s been widely hailed as one of the most attractive
luxury sedans on the road today.”
Photo: GM
(2011-06-22)
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