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 mains. 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, 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.
LS1
Chevrolet_Corvette_C5_LS1_engine.jpg
The LS1 was an evolution of the earlier LT small-block V8 (and is almost identical to the LT4 except for its aluminum construction). It is an all-aluminum 5.7 liter (5665 cc) pushrod engine and produces 350 hp (261 kW) and 375 ft·lbf (508 N·m) of torque. It shares its block with the higher-output LS6. The LS1 was on the Ward's 10 Best Engines list for 1998.
It is used in the following vehicles:
- 1997-2004 C5 Corvette base model
- 1998-2002 Chevrolet Camaro Z28, SS
- 1998-2002 Pontiac Firebird Formula and Trans-Am
- 2004 Pontiac GTO
LS6
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 liter (5665 cc) pushrod engine and produces 405 hp (302 kW) and 400 ft·lbf (542 N·m) of torque. It is used in the high-performance C5 Corvette Z06 model and the Cadillac CTS V-Series. The C6 Corvette Z06 will get a new 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.
Vortec engines
The Vortec 4800, 5300, and 6000 are cast-iron versions of the LS1 engine with different bore and stroke dimensions.
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 500 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.
LS2
GM_LS2_engine.jpg
The LS2 is the new base engine in the Corvette. It produces 405 hp (302 kW) and 400 lbf·ft (540 N·m) from a new 6.0 liter V8 based on the old LS1. It is similar to the high-performance LS6, and a higher-performance version of this engine is called the LS7.
Applications:
- 2005 Chevrolet Corvette
- 2005 Pontiac GTO
- 2005 Chevrolet SSR
- 2006 Chevrolet TrailBlazer SS
LS4
The LS4 is a smaller 5.3 L version of the Generation IV block. It is sold for use in trucks as the vortec 5300 LH6.
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
LS7
The LS7 is the latest high-power LS engine. It is a 7.0 L (7008 cc) 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 500 hp (373 kW) at 6200 RPM and 475 ft·lbf (644 N·m) at 4800 RPM with a 7000 RPM redline.
The LS7 will be 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.
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.
See also
- GM Small-Block engine - Generation I
- GM LT engine - Generation II
- Chevrolet Corvette
- LS1 article at AutoSpeed (http://www.autospeed.com/cms/A_2054/article.html)
- LS2 article at AutoSpeed (http://www.autospeed.com/cms/A_2062/article.html)