GM's Latest - The
2009 Corvette ZR1 and it's Supercharged LS9 Small-Block V-8.
The 2009 Corvette ZR1 will be moved by the most powerful production engine
ever built by GM.
writer: Courtesy Of GM
photographer: Courtesy of GM
When it arrives next summer, the 2009 Chevrolet Corvette ZR1 will be the
most powerful and fastest production car ever produced by General Motors,
with performance enabled by a new, supercharged 6.2L LS9small-block V-8
Incorporating the engineering experience already found in the CorvetteZ06's
LS7 engine and the new-for-2008 6.2L LS3 of the Corvette, GMPowertain is
targeting 100 horsepower per liter for the LS9, or 620horsepower (462 kW),
and approximately 595 lb.-ft. of torque (807 Nm);final SAE-certified power
levels will be available in early March 2008.
It is, indeed, the ultimate small-block engine for the ultimate Corvette.
"When you experience the LS9 in the Corvette ZR1, the terms performance and
refinement take on a new meaning," said Tom Stephens, group vice-president
for GM Powertrain and Quality. "The LS9 demonstrates an outstanding
performance range, with smooth drivability at low speeds, and surprisingly
fierce performance when the customer wants more power."
The enabler of the LS9's performance is a new, large positive-displacement
Roots-type supercharger - with a unique four-lobe design - developed for the
engine by Eaton. It is teamed with an integrated charge cooling system that
reduces inlet air temperature for maximum performance. The LS9 represents
the first of several new, supercharged small-block engines that will be
introduced in GM vehicles in the near future, each using superchargers of
"The small-block V-8 once again demonstrates it boundless horsepower
potential, versatile design and an architecture with proven quality,
durability and reliability," said Stephens. "We haven't yet realized the
small-block's performance potential."
More than just its tremendous peak horsepower and torque numbers, the
supercharged LS9 makes big power at lower rpm and carries it in a wide arc
to 6,600 rpm. GM Powertrain testing shows the engine makes approximately 300
horsepower (224 kW) at 3,000 rpm and nearly 320lb.-ft. of torque (434 Nm) at
only 1,000 rpm. Torque tops 585 lb.-ft.(793 Nm) at about the 4,000-rpm mark,
while horsepower peaks at 6,500rpm. The engine produces 90 percent of peak
torque from 2,600 rpm to6,000 rpm.
Heavy-duty and lightweight reciprocating components enable the engine's
confident high-rpm performance, while the large-displacement Eaton
supercharger pushes enough air to help the engine maintain power through the
upper levels of the rpm band.
"The sixth-generation design of the supercharger expands the 'sweetzone' of
the compressor's effectiveness, broadening it to help make power lower in
the rpm band," said Ron Meegan, assistant chief engineer. "To put it simply,
the low-end torque is amazing."
The LS9 is assembled by hand at GM's Performance Build Center, a unique,
small-volume engine production facility in Wixom, Mich., that also builds
the Corvette Z06's LS7 engine and other high-performance GMproduction
Cylinder block and reciprocating assembly details
The LS9's aluminum cylinder block features steel, six-bolt main bearing
caps, with enlarged vent windows in the second and third bulkheads for
enhanced bay to bay breathing. Cast iron cylinder liners - measuring4.06
inches (103.25 mm) in bore diameter - are inserted in the aluminum block and
they are finish-bored and honed with a deck plate installed. The deck plate
simulates the pressure and minute dimensional variances applied to the block
when the cylinder heads are installed, ensuring a higher degree of accuracy
that promotes maximum cylinder head sealing, piston ring fit and overall
Nestled inside the cylinder block is a forged steel crankshaft that delivers
the LS9's 3.62-inch (92 mm) stroke. It features as maller-diameter
ignition-triggering reluctor wheel and a nine-bolt flange - the outer face
of the crankshaft on which the flywheel is mounted - that provides more
clamping strength. Other non-supercharged6.2L engines, such as the base
Corvette's LS3, have a six-bolt flange. Atorsional damper mounted to the
front of the crankshaft features akeyway and friction washer, which also is
designed to support the engine's high loads.
Attached to the crankshaft is a set of titanium connecting rods and forged
aluminum pistons, which, when combined with the cylinder heads, delivers a
9.1:1 compression ratio. This combination is extremely durable and
lightweight, enabling the LS9's high-rpm capability.