GM LS engine

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The LS is Generation III and Generation IV, the latest evolution of General Motors' line of small-block V8 engines. The LS series is an evolution of the LT family but is all-aluminum and has 6-bolt main bearing caps. The LS engine has been the sole powerplant of the Chevrolet Corvette, and has also been used in the Pontiac GTO, the Cadillac CTS V-series, the Holden Commodore and Monaro since 1999 and the late Camaro/Firebird V8 models.

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Generation III

The Generation III small-blocks replaced the LT family in 1997. These shared the same rough displacement and bore spacing (4.4 in) as their cast iron predecessors but almost everything else was changed. The bore was reduced to 3.9 in and the stroke longer at 3.62 in for greater torque. The block was cast from aluminum (for cars) instead of iron and had a new intake and injection technology and coil-on-plug ignition. The traditional five-bolt pentagonal cylinder head pattern was replaced with a square four-bolt design, and the pistons are flat instead of domed. Even the cylinder firing order was changed.

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LS1

Image:Chevrolet Corvette C5 LS1 engine.jpg

The LS1 was an evolution of the earlier LT small-block V8 but shares little other than similar displacement and external dimensions. It is an all-aluminum 5.7 L (5665 cc) pushrod engine and produces between 305 and 350 hp (228 to 261 kW) and 375 ft·lbf (508 N·m) of torque, depending on the application. Beginning in 2001, the LS1 received the higher-flowing intake from the LS6, and a smaller camshaft to keep power at the same level; this also allowed GM to remove the EGR system. The block is very similar to that of the higher-output LS6; beginning in 2002, some LS1 engines were actually built using the LS6 block instead. The LS1 was on the Ward's 10 Best Engines list for 1998.

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LS6

Image:Chevrolet Corvette C5 Z06 LS6 engine.jpg

LS6 can also refer to a 454 in³ Chevrolet Big-Block engine of the 1970s

The LS6 is a higher-output version of Chevrolet's small-block LS1 engine. It is an all-aluminum 5.7 L (5665 cc) pushrod engine. The initial 2001 LS6 produced 385 hp (287 kW) and 385 ft·lbf (522 N·m), but the engine was modified for 2002 through 2004 to produce 405 hp (302 kW) and 400 ft·lbf (542 N·m) of torque. The LS6 was originally only used in the high-performance C5 Corvette Z06 model, with the Cadillac CTS V-Series getting the 405 hp engine later. Holden Special Vehicles also used the LS6 for its GTS models. For 2006, the Z06 replaced the LS6 with the new 7.0L LS7.

The LS6 shares its basic block design with the GM LS1 engine, but other changes were made such as windows cast into the block between cylinders. Improved intake, a titanium exhaust, higher-lift cams, and higher compression boosts output, and a new oiling system is better suited to high lateral acceleration.

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Vortec engines

The Vortec 4800, 5300, and 6000 are truck versions of the LS1 engine with different bore and stroke dimensions. The 4.8L and 6.0L versions are iron-block only, while the 5.3L has been built with both iron and aluminum blocks, depending on the application.

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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.

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L76

See also the Vortec 6000 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.

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LS2

Image:GM LS2 engine.jpg

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.

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LS4

Image:2006 Chevrolet Impala SS LS4 engine.jpg 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).

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LS7

Image:2006 Chevrolet Corvette Z06 LS7 engine.jpg 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 Roger Penske Mark Donahue concept car) also featured variations of the 7.0 L size.

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Holden Special Vehicles is widely tipped to use the LS7 on its 2007 GTS.

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.

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LS9

Early reports indicate that a 6.2 L LS9 derivative is due in 2010. It is said to be supercharged and produce 600 hp (447 kW) or more.

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See also

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External links

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