General Motors LS-Based Small-Block Engines

Overview

• Family of V8 and V6 engines by General Motors.
• Continuation of first- and second-generation Chevrolet small-block engines, very popular.
• Spans third, fourth, and fifth generations, with sixth expected soon.
• Available as crate engines.

Key Specifications

• Manufacturer: General Motors
• Designers: Tom Stephens, Ed Koerner
• Production: From 1997 to present

Layout

• Configuration: 90° V8, 90° V6
• Displacement: 293-511 cu in (4.8-8.4 L)
• Cylinder Bore: 3.78-4.185 in (96-106.3 mm)
• Piston Stroke: 3.3-4.125 in (83.8-104.8 mm)

Materials

• Cylinder Block: Aluminum, Cast iron
• Cylinder Head: Aluminum, Cast iron

Valvetrain & Combustion

• 16-valve, Overhead Valve (OHV), 2 valves per cylinder
• Fuel system includes Fuel injection and carburetors
• Fuel types: Gasoline, E85
• Oil System: Wet sump, Dry sump
• Cooling System: Water-cooled

Output

• Power Output: 255-755 hp
• Torque Output: 285-715 lb-ft

Dimensions

• Weight: 402-464 lb

History & Development

• "LS" Name: Originated from the Regular Production Option code LS1.
• Initial Launch: LS1 fitted in the Chevrolet Corvette (C5).
• Engines have powered various vehicles including Chevrolet Camaro, Pontiac Firebird, etc.
• Designed with modularity; many parts are interchangeable within generations.
• Popular for engine swaps in car enthusiast and hot rodding community.

Generation III (1997-2007)

• LS1: First of new architecture, 5.7L, used in Corvettes and GM F-Body (Camaro & Firebird), power improved over time.
• LS6: High-performance version, higher output, used in Corvette Z06 and Cadillac CTS V-Series.

Generation IV (2005-2020)

• Introduced high-displacement capabilities, displacement on demand technology.
• LS2: New base engine for Corvette, standard powerplant for GTO, improved torque.

Generation V (2013-present)

• Features include direct injection, piston cooling jets, active fuel management, and variable valve timing.
• LT1: First engine of Gen V, debuted in 2014 Corvette Stingray, increased displacement and advanced features.
• LT4: Supercharged variant, used in high-performance models like Corvette Z06.

Popular Models & Variants

• LS3: Base engine for Corvette in 2008, higher performance and efficiency.
• LSA: Supercharged engine variant used in Cadillac CTS-V.
• LS9: Supercharged, used in Corvette ZR1.

Issues & Considerations

• Early issues included piston slap and cylinder head cracking in certain models.
• Active Fuel Management (AFM) systems have had mechanical failures.

Future Developments

• Plans for a sixth generation LS engine underway, with significant investments by GM.

Notes

• LS Swap: Popular in the car modification community due to the availability of parts and ease of swaps.
• Modifications: LS engines support a high degree of aftermarket modifications and performance upgrades.

These notes summarize the development, specifications, and applications of the General Motors LS-based small-block engines. They focus on the historical context, variations through generations, and specific technical details essential for understanding the evolution and impact of these engines.