GM LS engine

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GM LS engine
Manufacturer	General Motors
Also called:	GM Vortec engine
Production:	1997–present
Predecessor:	GM LT engine, Chevrolet Small-Block engine, Chevrolet Big-Block engine

The LS series is a new design intended as the only V-8 engine utilized in General Motors' line of RWD cars and trucks. The LS series was a clean sheet design with nothing in common with the classic Chevrolet small block V8. The LS is all-aluminum and has 6-bolt main bearing caps.

The LS engine has been the sole powerplant of the Chevrolet Corvette since 1997 and has seen use in a wide variety of other General Motors vehicles, ranging from sport coupes to full size trucks. Due to the engine's relatively compact external dimensions compared to its displacement and power output, the engine family is also a popular choice for kit cars, hot rods and even light aircraft.

Contents 1 Generation III 1.1 LS1 1.2 LS6 2 Generation IV 2.1 L76 2.2 L98 2.3 LS2 2.4 LS3 2.5 LS4 2.6 LS7 2.7 LS7.R 2.8 LSX 2.9 LS9 2.10 LSA 3 Vortec engines 4 Problems 5 See also 6 References 7 External links

[edit] Generation III

The Generation III V-8 engines replaced the LT family in 1997. These shared the same 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. 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. 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, so that the LS series now corresponds to the firing pattern of other modern V8 engines (for example the Ford Modular V8).

[edit] LS1

The LS1 shares little other than similar displacement, external dimensions, and rod bearings, with its predecessor. It is an all-aluminum 5.7 L (346 in³) pushrod engine and was rated between 305 - 350 hp (227 to 261 kW) and 335-365 ft·lbf (454-494 N·m) of torque in North America, depending on the application. 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 2004 Pontiac GTO was rated at 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 milder camshaft to keep power at the same level; this also allowed GM to remove the exhaust gas recirculation (EGR) system (Camaro/Firebird only; 97-00 Corvette LS1 never used an 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:

• 1997-2004 Chevrolet Corvette C5, excluding Z06
• 1998-2002 Chevrolet Camaro Z28, SS
• 1998-2002 Pontiac Firebird Formula, Trans Am, Trans Am WS6
• 2004 Pontiac GTO
• 1999-2005 Holden Commodore Ute
• 1999-2005 Holden Commodore (VT, VX, VY, VZ)
• 1999-2005 Holden Statesman (WH, WK, WL)
• 1999-2005 Holden Caprice (WH, WK, WL)
• 1999-2004 Holden Special Vehicles (all V8 models)
• 2001-2005 Holden Monaro CV8
• 2006-2007 Elfin MS8 Streamliner

[edit] LS6

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

The LS6 is a higher-output version of GM's 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 400 hp engine later. The V-Series used the LS6 for two years before being replaced by the LS2 in 2006. For 2006, the Z06 replaced the LS6 with the new 7.0L LS7.

The LS6 shares its basic block architecture with the GM LS1 engine, but other changes were made to the design such as windows cast into the block between cylinders, improved main web strength and bay to bay breathing, an intake manifold and MAF-sensor with higher flow, a camshaft with higher lift and more duration, a higher compression ratio and a revised oiling system better suited to high lateral acceleration. ^[1]

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

Applications:

• 2001-2004 Chevrolet Corvette C5 Z06
• 2004-2005 Cadillac CTS V-Series

[edit] Generation IV

In 2004, the Generation III was superseded by the Generation IV. This category of engines has provisions for high-displacement ranges up to 7.0 L and power 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 4 cylinders in alternating fashion from side to side and front to back 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 GM 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. It has been reported that the LS3 and an upcoming 6.0L Vortec engine represent the final two designs to be considered in the Generation IV engine family, and that future designs - expected around 2009 - will be part of the Generation V engine family.^[2]

[edit] L76

See also the Vortec 6000 L76

L76 was originally Holden's version of the 6.0 L (364.3 in³) Generation IV engine. While early models lacked the displacement on demand technology found on some versions, this feature is enabled on the 2008 Pontiac G8. The engine also meets Euro III emissions requirements. Output is 348 hp (260 kW) at 5600 rpm and 376 ft·lbf (510 N·m) at 4400 rpm for the Holden variant, and 361 hp (269.8 kW) and 385 ft·lbf of torque (526.5 N·m) for the G8 GT.^[3]

Applications:

• 2006 Holden VZ Commodore
• 2008 Pontiac G8

[edit] L98

For the tuned-port Generation I engine of the same RPO, see Chevrolet 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:

• 2006-2007 Holden VE Commodore
• 2006-2007 Holden WM Statesman / Holden WM Caprice
• 2007-2008 Chevrolet Lumina SS
• 2007-2008 Chevrolet Caprice SS

[edit] LS2

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:

• 2006-2007 Cadillac CTS-V

• 2005-2007 Chevrolet Corvette
• 2005-2006 Chevrolet SSR
• 2006-2008 Chevrolet TrailBlazer SS
• 2004-2007 Holden Special Vehicles (all V8 models)
• 2005-2006 Pontiac GTO
• 2008-2010? Saab 9-7X Aero
• 2005-2006 Vauxhall Monaro VXR

[edit] LS3

LS3 can also refer to a 402 in³ Chevrolet Big-Block engine of the 1970s

The LS3 was introduced as the Corvette's new base engine for the 2008 model year. It produces 430 hp (321 kW) at 6000 rpm and 424 ft·lbf of torque (575 N·m) at 4400 rpm and is SAE certified. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in creating a displacement of 6.2 L (376 in³), 0.2 L larger than the LS2. It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551" lift, a revised valvetrain with 6 mm offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.

The L76/L92/LS3 cylinder heads are the most advanced heads to date. They use 2.165" (55 mm) intake valves, and 1.59" (40.4 mm) exhaust valves. For use with 4" and larger bores, they allow for over 600 hp naturally aspirated. Improved manufacturing efficiency makes these heads cheaper than the outgoing LS6 heads, and severely undercuts aftermarket heads. The large valves, however, limit maximum rpm - 6000 in the L76 (with AFM), and 6600 in the LS3 (with hollow stem valves).

In addition to the above, a dual mode exhaust package with a bypass on acceleration is available. The dual-mode exhaust uses vacuum-actuated outlet valves, which control engine noise during low-load operation, but open for maximum performance during high-load operation. The system is similar to the C6 Z06, but uses a 2.5" diameter exhaust compared to the Z06's 3.0". Power is boosted to 436 hp (325 kW) and 428 ft·lbf (580 N·m) with this option.

Applications:

• 2008-present Holden Special Vehicles (all V8 models)
• 2008-present Chevrolet Corvette
• 2009 Pontiac G8 GXP (source: Pontiac web site, "Upcoming Vehicles," 3-16-2008)

[edit] LS4

LS4 can also refer to a 454 in³ Chevrolet Big-Block engine of the 1970s

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.

This engine is adapted for transverse front-wheel drive applications. In order to fit into the smaller engine compartments designed for V-6s, 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:

• 2006-2008 Chevrolet Impala SS
• 2006-2007 Chevrolet Monte Carlo SS
• 2005-2008 Pontiac Grand Prix GXP
• 2008 Buick LaCrosse Super

[edit] LS7

LS7 can also refer to a 454 in³ Chevrolet Big-Block engine of the 1970s

The LS7 is a 7.0 L (427.6 in³) engine, 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).

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 setting a new record for a production overhead valve pushrod engine.^{[citation needed]} 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 constraints 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. Most of these engines are installed in the Z06, but some are also sold to individuals by GM as a crate engine. It was rumored for several years now that Holden Special Vehicles will be using the LS7 in one of its vehicles. This has recently been confirmed, HSV will use its own version of the engine in its new E-Series W427, still based on the Holden Commodore. The HSV-tuned engine will produce 377 kW (510 hp). The vehicle was shown at the Melbourne Motor Show 29 February 2008.^[4]

Applications:

• 2006-2008 Chevrolet Corvette Z06
• 2008 Holden Special Vehicles W427

[edit] LS7.R

The LS7.R engine is a variation of the LS7 used in the highly successful C6.R American Le Mans Series racecar. It was crowned as Global Motorsport Engine of the Year by a jury of 50 race engine engineers on the Professional Motorsport World Expo 2006 in Cologne, Germany.

[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. It offers displacements ranging from 364 cubic inches to 511 cubic inches (4.25" Bore x 4.5" Stroke) 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, set to be available in authorized dealerships and retailers on March 31, 2007.^[5]

[edit] LS9

The LS9 is a 6.2 L (376 in³) supercharged engine, based on the LS3; the LS7 block was not used due to the higher cylinder pressures created by the supercharger requiring the thicker cylinder walls of the LS3. Cylinder dimensions are now 4.06 in (103.25 mm) bore with a 3.62 in (92 mm) stroke. It is equipped with an Eaton four-lobe Roots type supercharger. Power output is 638 hp (476 kW) at 6500 rpm and 604 lb·ft (819 N·m) of torque at 3800 rpm.

Applications:

• 2009 Chevrolet Corvette ZR1

[edit] LSA

The supercharged 6.2 L LSA is similar to the LS9 and scheduled to debut in the 2009 Cadillac CTS-V. Producing an estimated 550 hp (410 kW) of power and 550 ft·lbf (745 N·m) of torque, the LSA features a smaller 1.9 L capacity supercharger rather than the 2.3 L variant of the LS9. Other differences include a slightly lower 9.0:1 compression ratio, single unit heat exchanger and cast pistons.

Applications:

• 2009 Cadillac CTS V-Series

[edit] Vortec engines

Versions of both the Generation III and Generation IV V8 have also been used in trucks and SUVs. These are usually branded as GM Vortec engines.

[edit] Problems

In the early production run of the LS-series engine, some engines encountered abnormal amounts of 'piston slap' - a problem caused by too much clearance between the cylinder bore and the piston. ^[6] 'Piston Slap' sometimes sounds more like a knock or the sound of a diesel engine running, it is also typically worst when the engine is cold and lessens as the engine reaches operating temperature. The noise of 'Piston Slap' often is louder when listening for it below the oil pan.

[edit] See also

• GM Small-Block engine - Generation I
• GM LT engine - Generation II
• Chevrolet Corvette

[edit] References

[edit] External links

• LS1 article at AutoSpeed
• LS2 article at AutoSpeed