GM LS engine: Encyclopedia II - GM LS engine - Generation IV

GM LS engine - Generation IV

Hot on the heels of the Generation III was Generation IV. These big-bore engines are some of the largest small-blocks yet, and will quickly replace the previous generation. Displacement ranges up to 7.0 L and output to 505 hp (373 kW). Generation IV will later feature displacement on demand, a technology that allows one bank of cylinders to be deactivated. It will also offer variable cam phasing and 3-valve per cylinder designs, a novelty in a pushrod engine.

GM LS engine - L76

L76 is Holden's version of the 6.0 L Generation IV engine. It lacks the displacement on demand technology found on some versions, but meets Euro III emissions requirements. Output is 348 hp (260 kW) at 5600 rpm and 376 ft·lbf (510 N·m) at 4400 rpm.

GM LS engine - LS2

The LS2 is the new base engine in the Corvette. It produces 400 hp (298 kW) at 6000 rpm and 400 ft·lbf (542 N·m) at 4400 rpm from a new 6.0 L (364.3 ci) V8 based on the old LS1. It is similar to the high-performance LS6, but with an improved power peak and more torque throughout the RPM range.

Applications:

• 2005-2006 Chevrolet Corvette
• 2005-2006 Pontiac GTO
• 2005-2006 Chevrolet SSR
• 2006 Chevrolet TrailBlazer SS
• 2006 Cadillac CTS-V
• 2005-2006 HSV GTO - Holden Special Vehicles
• 2005-2006 HSV Clubsport - Holden Special Vehicles
• 2005-2006 HSV Grange - Holden Special Vehicles
• 2005-2006 HSV Maloo - Holden Special Vehicles
• 2005-2006 HSV Senator - Holden Special Vehicles
• 2005-2006 Vauxhall Monaro VXR

GM LS engine - LS4

The LS4 is a smaller 5.3 L (325 ci) version of the Generation IV block. Though it has the same displacement as the Vortec 5300 LH6, it differs in that it has an aluminum block rather than an iron one.

A version of this engine is adapted for transverse front wheel drive application, the first time a small-block family engine has been used in this manner. Displacement on Demand is also used. Output of this version is 303 hp (226 kW) and 323 ft·lbf (438 N·m).

Applications:

• 2006 Chevrolet Impala/Monte Carlo SS
• 2006 Pontiac Grand Prix GXP

GM LS engine - LS7

The LS7 is the latest high-power LS engine. It is a 7.0 L (427.6 ci) unit, based loosely on the LS2. The block is changed, with a larger 4.13 in (104.9 mm) bore and longer 4.00 in (101.6 mm) stroke than the LS2. The small-block's 4.4 in (111.8 mm) bore spacing is retained, requiring pressed-in cylinder liners. The crankshaft, and main bearing caps are forged steel for durability, the connecting rods are titanium, however cast pistons were retained to avoid the piston slap issues that forged pistons have on startup. The two-valve arrangement is retained, though the titanium intake valves have grown to 2.20 in (55.9 mm) and sodium-filled exhaust valves are up to 1.61 in (40.9 mm).

Peak output is 505 hp (377 kW) at 6300 rpm and 470 ft·lbf (637 N·m) at 4800 rpm with a 7000 rpm redline.

The LS7 is hand-built by the General Motors Performance Build Center in Wixom, Michigan. Up to 15,000 LS7s will be produced each year starting in 2005. Most of these engines are installed in the Z06, but some are also sold to individuals by GM as a crate engine.

The 7.0 L mark had already been reached by the LS-series of racing engines, famously in the 24 Hours of Le Mans Corvette C5R. GMMG Berger Camaro ZL1s made late in 2002 and GMMG Berger Dick Harrell Camaros (inspired by the Penske Donahue concept car) also featured variations of the 7.0 L size.

Applications: 2006 Corvette Z06

Chevrolet also had an experimental big-block engine named LS7 in the late 60's that were supposed to be in the 1970 Corvette, but it never materialized. Some LS7 heads were sold as an aftermarket product in 1971 and 1972 though.

Adapted from the Wikipedia article "Generation IV", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki