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[Press] 2005 Corvette: Most Standard Power Ever

Rob

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From: http://www.gminsidenews.com
2005 CORVETTE ENGINE: MOST STANDARD POWER EVER


DETROIT - GM announced the 2005 Corvette will feature the most powerful standard engine ever in Corvette history: the 400 horsepower, 6.0-liter, small-block V-8.

The new 6.0-liter LS2 is part of the fourth generation of GM’s small-block engines. The LS2 raises the bar for standard performance in the Corvette, delivering 400 horsepower at 6000 rpm and 400 lb.-ft. of torque at 4400 rpm – an increase of 50 horses and 40 lb.-ft. of torque over the previous Corvette’s LS1 engine.

LS2 engine’s range of power and torque is broad and very usable in everyday driving. This engine is smoother, and more refined, but at the same time retains tire-thrashing output.

Design changes
LS2 incorporates several significant changes over the LS1 that improves performance, reliability and serviceability:

- All-new aluminum block casting incorporates provisions for external knock sensors and revised oil galleries; external sensors improve serviceability
- Cylinder bore diameter increased to 101.6 mm (4.00 inches), increasing displacement to 6.0 liters
- Camshaft lift increased to take advantage of increased cylinder head flow
- Camshaft sensor relocated from the rear of the block to the front of the block provides room for new oil galleries
- Flat-top piston design with lower ring tension reduces friction
- Piston floating wrist pins help quiet the engine
- Redesigned, “wingless” oil pan with cast baffling has reduced mass and provides superior oil control under high-performance driving maneuvers
- Revised exhaust manifolds are 33 percent lighter
- More efficient ignition coils require less energy to provide a comparable spark
- Compression raised to 10.9:1
- Larger, 90-mm single-blade throttle body
- Reduced-mass water pump design with improved sealing capability
- Engine “redline” raised to 6500 rpm
- Revised and more powerful engine controller incorporates all electronic throttle control functions.
- Mass has been reduced by 7 kilograms on the automatic version.

Cylinder heads for the LS2 are derived from designs used in previous Z06 models. Raised intake ports and an unshrouded-valve combustion chamber (with the flat top pistons) produces a more efficient swirl of the air/fuel mixture. This efficiency enables a higher 10.9:1 compression ratio, which increases fuel economy and horsepower.

Valves measure 2 inches for the intake and 1.55 inches for the exhaust. The valve springs also have been upgraded to withstand the engine’s increased power and rpm range.

The LS2’s new oil pan provides better oil control under the extreme demands of high-rpm/high g-force driving maneuvers. The elimination of the previous “gull wing” oil pan design also reduces the engine’s oil capacity from 6.5 quarts to 5.5 quarts with a dry filter.

Exhaust manifolds are reworked to increase the efficiency and reduce the mass. Wall thickness of the manifolds is reduced from 4 mm to 3 mm, eliminating weight and helping enhance airflow by approximately 4 percent.

Features of the LS2 are incorporated as continuous improvements to later versions of the Gen III engine, including long-life, iridium-tip spark plugs; pistons with full floating wrist pins; a redesigned water pump that significantly reduces the probability of a leak; and a stronger, long-life timing chain.

The Gen IV builds upon the strengths of the Gen III small-block architecture, including:

Aluminum, deep skirt block (structural rigidity and operating smoothness is enhanced because the engine block extends below the crankshaft centerline) with iron cylinder bore liners: The lightweight block is cast from 319-T5 aluminum with cast-in-place iron cylinder bore liners. A die-cast aluminum valley cover and upper deck rails tie together the cylinder banks, increasing torsional and bending stiffness.

A 90-degree cylinder bank arrangement and 4.40-inch bore centers – the distance between the center of one cylinder and the center of the next.

Two horizontal cross bolts for each main bearing cap complement four traditional vertical main cap bolts and contribute additional strength and smoothness to the engine’s rotating assembly.

Gerotor oil pump fits the shallow oil pan and offers superior pumping capability.

Balanced cylinder head design performance/efficiency with identical airflow and energy direction for each cylinder.

A separate ignition coil pack and short spark plug wire for each cylinder maximize the efficiency of the delivered coil energy, enhancing fuel efficiency and power.

Electronic throttle control system improves driveability and reduces overall system complexity by eliminating typical conventional mechanical items, such as the idle air control motor, cruise control module and throttle relaxer (traction control).

Because the LS2’s new engine controller incorporates ETC commands, the separate ETC module used on the LS1 is no longer required. This allows faster communication of the controller to the throttle, as well as reducing the mass and complexity of the system. Additionally, emissions are slightly improved with the damping of unnecessary throttle movement.

Improvements to the engine’s crankcase breathing and ventilation were made similar to the LS6 engine, including moving the crankcase ventilation system’s PCV valve away from the rocker covers and into the block valley.

Other Advances: Exhaust System

Advances in catalyst substrates made possible catalytic converters that are at the same time more effective and less restrictive for the LS2’s exhaust. The new converters are mounted closer to the exhaust manifold for quicker lightoff and reduced cold-start emissions. As a result, the more restrictive quad catalyst design of the LS1 – with its small, auxiliary “pup” converters – was not necessary to meet emissions requirements. An additional benefit of the exhaust system’s development was the elimination of the LS1’s air injection reaction system.

Sharp angles in the tubing have been replaced with more gradual bends. A larger muffler volume and tri-flow technology eliminated certain periods prone to unwanted noise, particularly between 1500 and 2400 rpm. An inline muffler that flows more efficiently replaces the laterally mounted muffler in the C5. These changes, coupled with one converter per exhaust bank, reduced backpressure in the system and contributed to the LS6’s 400 horsepower and 400 lb.-ft. of torque.​
 

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