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LS9 Engine Guide: Specs, Features, & More

LS9 Engine

Most would agree that the Corvette’s no holds barred approach to performance excellence is high up on the list of the iconic American sports car’s most beloved characteristics. Just when one is inclined to believe that the Corvette’s overall output has peaked, with no perceivable way to provide any further noteworthy gains, GM’s design and development team shifts gears once more.

There has likely been no better case study of this unceasing dedication to forward progress than the LS9. Just when many had begun to question whether or not the further development of GM’s famed LS platform had plateaued, the LS9 burst onto the scenes, unequivocally elevating the 2009 ZR1’s performance merit and silencing all skeptics.

The History of the LS9

LS9 Engine with cover

In more ways than one, the LS9 was born out of what could easily be referred to as GM’s darkest hour. The financial crisis of 2008 had taken its toll on the illustrious automaker, and the piper had to be paid. With nowhere to go but under, GM filed for Chapter 11 reorganization on June 1, 2009, in Manhattan New York federal bankruptcy court.

Though GM would ultimately receive a taxpayer-funded bailout that would spare the automaker from demise, this did not come without cost. In the months to follow, GM would be forced to shudder 4 of its 8 brands, nixing Pontiac, Saab, Saturn, and Hummer from its portfolio. The automotive giant was also forced to eliminate 25% of its total workforce.

Despite this corporate turmoil, subsequent Corvette design and development efforts were left largely unchecked. Against all odds, plans for the Corvette’s latest power plant remained on the table. Those with knowledge regarding the specifics of this upcoming engine breathed a collective sigh of relief.

The engine in question was to be GM’s latest addition to its legendary LS platform, and held significant promise to become one of the most beastly underhood additions that the Corvette had ever been the recipient of. The LS9, as it was to be called, was developed out of necessity, as GM’s engineering staff knew that outfitting the upcoming ZR1 with a more robust powerplant than its already available sibling, the Z06, would be nothing short of a monumental task.

With expectations mounting, the race was on to produce an engine fitting of its prestigious placement under the hood of the ZR1. GM’s answer came in the form of a refined version of the base Corvette’s LS3 block, high-flow cylinder heads, and a four-lobed supercharger. The culmination of each facet proved to be nothing short of extraordinary, and GM’s highest-performance production engine to date was born.

LS9 Technical Specs and Configurations

At the heart of the 376 cubic-inch, LS9 is a 319-T7 aluminum block, which is essentially a more robust version of that which was used in LS3 production. Blocks used in the assembly of LS9 engines featured optimally sized bulkhead “windows”, which led to a 20% increase in strength over blocks used in prior LS production. It is widely speculated that this was done in a bid to make the LS9’s block more tolerant to the stresses of forced induction, which it was slated to endure.

The aluminum composition of the LS9’s block proved to be quite weight-reductive, weighing in nearly 100-pounds lighter than a conventional cast-iron block. This block was also fitted with cast-iron cylinder liners and featured a deep-skirt design to reduce vibration under varying operational loads. The LS9’s cylinder bores measure 4.065”, with a 3.622” stroke.

In a further bid to eliminate weak points that could be exposed by the pressures of forced induction, every LS9 block is deck plate honed. This enhances engine life and maximizes output by providing a higher-quality seal between the engine’s piston rings and cylinder bore. The LS9 utilizes a 9.1:1 compression ratio and its cylinders are fitted with polymer-coated forged pistons, which ride atop titanium connecting rods and a dropped-forged micro-alloy steel crankshaft.

The LS9’s block comes fitted with GM’s rotocast cylinder heads, which are rotated throughout the casting process as the molten alloy cools. This significantly reduces porosity, thereby bolstering structural integrity. The LS9’s heads are also of a “high-flow” design, which optimizes airflow. This, in turn, allows for the best possible use of the engine’s supercharger derived intake air.

Blue ZR1 Corvette with LS9 engine

Much of the LS9’s stellar output can be attributed to its use of a sixth-generation, 2.3L Roots-style supercharger. This supercharger consists of a 4-lobe design and tops out at 15,000 RPM. This air is cooled before entering the engine’s cylinders by a twin-brick style intercooler, leading to enhanced combustion and increased output.

In an effort to curb oil starvation during periods of intense acceleration and cornering, the LS9’s oil capacity was increased beyond that of the Z06’s LS7 powerplant. The LS9 features a total oil capacity of 10.75 quarts. This allows the LS9 to withstand 30% more g’s, without suffering a reduction in lubrication.

All things considered, the LS9 produces 638 horsepower, and 604 lb-ft of torque, while also propelling the ZR1 to ¼ mile times of 11.3 seconds. Additionally, the LS9 equipped ZR1 posts 0-60 MPH times of only 3.4 seconds and 0-100 MPH times of 7 seconds.

LS9 Specs Index

Horsepower: 638hp @ 6500 rpm

Torque: 604 lb-ft @ 3,800 rpm

Compression Ratio: 9.1: 1

Displacement: 376 cubic inches (6.2L)

Cylinder Bore: 4.065” (103.25 mm)

Stroke: 3.622” (92mm)

Side view of LS9 engine

LS9 Specialty Uses

Even after the LS9 was relieved from its duties under the hood of the Corvette, the iconic powerhouse remained a popular choice for those in search of the perfect crate engine for their build. The LS9 has found a home in the engine bay of everything from Camaros to Tahoes, and all points in between.

Holden Special HSV GTS-R W1

When specialty car manufacturer Holden Special Vehicles decided to bid farewell to their storied Commodore model in 2017, they concluded that it was only fitting for the line to go out with a bang. To make this happen, Holden outfitted all of their final year Commodores with LS9 engines.

These LS9 equipped Holden Commodores received a significant amount of media attention, as it seemed that gearheads the world over were eager to see just what applications the LS9 would be best suited for.

Pavement Pounding Performance

Even today, over a decade later, the LS9 captivates the minds of automotive performance enthusiasts from around the globe. Born from a pedigree of precision engineering, this engine made all stand and take note from the very date of its unveiling. As a result, the LS9 equipped ZR1 proved that the Corvette could compete on any stage, and take on any competitor, foreign or domestic.