The goal for the LS6 was to improve upon the 2000 LS1's 345 hp by ten percent. "Part of how we got there was through an extension of our power curve," explains Bill Nichols, powertrain vehicle system engineer for Corvette. "And what that really means is extending the operating range of the engine by taking advantage of the small block and its light weight."

In order to extend the range of the engine, a number of changes had to be made to the Gen III block, heads, and valvetrain, as well as the intake and exhaust manifolds.

LS6 Engine

LS6 Specifications

OHV V-8, 5.7 liters (346 cid)

Power: 385 bhp @ 6,000 rpm

Torque: 385 lb.-ft. @ 4,800 rpm

Transmission: Six-speed manual

Rear axle ratio: 3.42:1

Performance

0 to 60 mph: 4.0 sec (average)

Quarter-mile: 12.6 sec @ 114 mph

BACK TO TOP

Revised Engine Block

In the previous Gen III engine, the main bearing webs that separate between pairs of cylinders and bring the block structure down the main bearing journals for strength also cause a build-up of pressure in the crankcase as the pistons pump air on their downstroke.

In order to balance the pressure within the crankcase, small slots are cast into the webs underneath the piston travel area. Approximately the size of a fifty-cent piece, the holes open up the bottom of the block and help share that working effort with the other cylinder pairs in the crankcase. With the pistons pumping less air, there is a reduced parasitic loss which enables higher rpm.

The reduced crankcase pressure also allows the engine oil to drain from the valvetrain back into the crankcase more quickly, so that even with higher engine operating speeds, lubrication is not compromised.

Redesigned Air Cleaner

An additional pathway has been added to the front of the air cleaner to reduce restriction in the air cleaner system and increase air intake. "We unplugged the air cleaner, in a manner of speaking, to get enough air to breathe at 6,500 rpm and to generate 385 bhp," Nichols explains. "Additionally, the front fascia openings now feed cool air into the air cleaner system."

BACK TO TOP

New Mass Air Flow Sensor Design

The mass air flow sensor was slightly altered to increase the intake diameter (ID) and increase air flow.

New Intake Manifold Design

As mentioned earlier, the LS6 shares its new intake manifold with the LS1. The new design reduces air intake restriction and improves flow into the heads, for better breathing.

Unique New Camshaft Design

As the air intake comes through the new manifold in greater volume and in a less disturbed fashion, it is important for that air to enter the combustion chamber as quickly as possible to produce power.

For this reason, the LS6 has a new camshaft design that incorporates a unique camshaft profile. The new camshaft increases valve lift from 12.7 mm to 13.3 mm, for an improvement of five percent. The additional lift allows more air into the chamber, enabling more power to be produced.

Higher-Rate Valve Springs

Intake and exhaust valves are the same specifications as for the LS1, but the valve springs are manufactured from a higher strength material and designed with increased load capability to enable a 6,500 rpm redline.

BACK TO TOP

New Cylinder Head Design

Improving the breathing capabilities of the intake manifold and high-lift camshaft profile would be an exercise in futility unless the cylinder head was also redesigned to accommodate this increased capacity. The LS6 has a new cylinder head design to enhance the breathing characteristics of the engine for added performance and to enable the extension of the engine's operating range.

The cylinder heads incorporate new ports to improve flow of the combustion gases. Doing so improved flow by ten percent. The cylinder heads have also been cast to increase the compression ratio of the LS6 to 10.5:1, an increase from the 10.1:1 ratio of the LS1. "The new cylinder heads are the heart and soul of the new LS6," enthuses Nichols.

Increased-Capacity Fuel Injectors

Fuel-injector capacity has been increased by ten percent, from 3.3 grams/sec. to 3.6 grams/sec.