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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 was a clean sheet design, drawing on the heritage of the classic small-block, but is all-aluminum and has 6-bolt main bearing caps. The LS engine has been the sole powerplant of the C5 and C6 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 1998-2002 Camaro and Trans Am models.

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[edit] Generation III

The Generation III small-blocks replaced the LT family in 1997. These shared the same rough displacement and bore spacing (4.4") 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 low end torque. The engine blocks were cast in aluminum for car applications, and iron for most truck applications (notable exceptions include the Chevrolet TrailBlazer). The engine also introduced coil-on-plug ignition to the small-block V8. The traditional five-bolt pentagonal cylinder head pattern was replaced with a square four-bolt design, and the pistons are of the flat-topped variety. The cylinder firing order was changed to 1-8-7-2-6-5-4-3.

[edit] LS1

Image:1998ChevroletCamaroZ28-engine.jpg

The LS1 shares little other than similar displacement, external dimensions, and rod bearings, with the earlier small-block V8 engines. It is an all-aluminum 5.7 L (346 in³) pushrod engine and was rated between 288 - 345 hp (212 to 257 kW) and 325-350 ft·lbf (439-475 N·m) of torque in North America, depending on the application. However, regardless of application, the LS1s used in vehicles would usually produce an actual 345 hp (257 kW) measured at the flywheel. In Australia, continuous modifications were made to the LS1 engine throughout its lifetime, reaching 382 hp (285 kW) in the HSV's YII series and a Callaway modified version, named C4B, was fitted to HSV GTS models producing 402 hp (300 kW). The version fitted to the Pontiac GTO featured a higher-lift camshaft to produce 350 hp (261 kW) and 365 ft·lbf (494 Nm) of torque. 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 exhaust gas recirculation (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.

Applications:

[edit] 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 (346 in³) 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. The V-Series used the LS6 for two years; it was replaced with the LS2 in 2006. 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. An improved intake manifold, higher-lift cam, and higher compression ratio boost output compared to the LS1, and a new oiling system is better suited to high lateral acceleration.

The casting number, located on the top rear edge of the block, is 12561168.

[edit] 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.

[edit] Generation IV

In 2004, the Generation III was superseded by the Generation IV. These big-bore engines are some of the largest small-blocks yet, and were quickly phased in to replace the previous generation. Displacement ranges up to 7.0 L and output to 505 hp (373 kW). Building upon the Generation III design, Generation IV was designed with displacement on demand in mind, a technology that allows one bank of cylinders to be deactivated. It can also accommodate variable valve timing. A 3-valve per cylinder design was originally slated for the LS7, which would have been a first for a pushrod engine; but the idea was shelved owing to design complexities and when the same two-valve configuration as the other Generation III and IV engines proved to be sufficient to meet the goals for the LS7.

[edit] 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.

Applications:

[edit] L98

The L98 is a slightly modified version of the L76, devoid of some redundant hardware relating to displacement on demand. Power increased to 362 hp (270 kW) at 5700 rpm and 391 ft·lbf (530 Nm) at 4400 rpm.

Applications:

[edit] LS2

Image:GM LS2 engine.jpg

The LS2 was introduced as the Corvette's new base engine for the 2005 model year. It produces 400 hp (298 kW) at 6000 rpm and 400 ft·lbf (542 N·m) at 4400 rpm from a slightly larger displacement of 6.0 L (364.3 in³). It is similar to the high-performance LS6, but with an improved power peak and more torque throughout the rpm range. The E-series HSV's are equipped with a 412 hp (307 kW) and 406 ft·lbf (550 Nm) version.

Applications:

[edit] LS4

Image:2006 Chevrolet Impala SS LS4 engine.jpg

The LS4 is a smaller 5.3 L (325 in³) 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 and it uses the same cylinder head as the Generation III LS6 engine.

A version of this engine is adapted for transverse front-wheel drive application. In order to fit into the smaller engine compartments designed for V-6s, in the front-wheel drive Pontiac Grand Prix GXP, for instance, the LS4 engine block had to be shortened by one inch. Displacement on Demand is also used. Output of this version is 303 hp (226 kW) and 323 ft·lbf (438 N·m).

Applications:

[edit] 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 in³) unit, based on the Gen IV architecture. The block is changed, with a larger 4.125 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 forged titanium, and the pistons are hypereutectic, possibly to keep the relatively small mass pistons in check when they thermally expand at operating temperature. The two-valve arrangement is retained, though the titanium intake valves by Del West have grown to 2.20 in (55.9 mm) and sodium-filled exhaust valves are up to 1.61 in (40.9 mm). The LS7 is also the only current Gen IV engine to feature dry sump lubrication.

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. During GM's reliability testing of this engine in its prototype phase, the LS7 was remarked to have been repeatedly tested to be 8000 rpm capable, although power was not made at that rpm level, due to the restraints of the camshaft's profile and the intake manifold ability to flow required air at that engine speed.

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. No other vehicles are currently confirmed to use the LS7 in the future.

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.

Applications:

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.

[edit] LSX

At the 2006 SEMA show, GM Performance Parts introduced the LSX engine, an all-new cast-iron racing block based on the LS7 engine. It was designed with help from drag racing legend Warren Johnson, and despite being based on GM's small-block design, it offers displacements ranging from 364 cubic inches to over 500 cubic inches And is capable of withstanding 2500 bhp. This block incorporates two extra rows of head-bolt holes per bank for increased clamping capacity. The six bolt steel main caps are the same ones used on the LS7 engine. The engine debuted at the auto show in a customized 1969 Camaro owned by Reggie Jackson. The LSX will be available starting the second quarter of 2007.[1]

[edit] LS9

Early reports indicate that a 6.2 L LS9 derivative is due in 2008. Displacement was a reportedly decreased for a thicker cylinder wall, to promote a stronger cylinder to deal with the rigors of possibly forced induction. A picture of this motor was seen drifting around on the internet, and it seems to be equipped with a positive displacement supercharger and is stated to produce 650 hp (485 kW).

[edit] See also

[edit] External links

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