__________________________________________________________________________________
5.7L V8
LS1 - 1998



__________________________________________________________________________________

“The genuine Chevrolet LS1 has a smooth idle that belies
the torque available from about 1500 rpm up to 5000.
Redlined at 6000 rpm, the forceful 5.7-liter engine has more
horsepower and torque-345 bhp and 350 lb.-ft.-- than either
the LT1 V-8 or LT4 V-8 variants of last year...”
Road & Track
February, 1997



__________________________________________________________________________________
Product Specifications

Type: 5.7L V8	Bore x Stroke: 99.00 x 92.00 mm (3.90 x 3.62 in)	Materials
Displacement: 5665 cc (346 CID)	Fuel System: SEQUENTIAL FUEL INJECTION	Block: CAST ALUMINUM
Compression Ratio: 10.1:1	Horsepower: 345 @ 5600 rpm (Y) 305 @ 5200 rpm (F)	Cylinder Head: CAST ALUMINUM
Valve Configuration: OVERHEAD VALVES	Torque (lb-ft): 350 @ 4400 rpm (Y) 335 @ 4000 rpm (F)	Intake Manifold: COMPOSITE
Assembly Site: ROMULUS, MI	Maximum Engine Speed: 6000 rpm	Exhaust Manifold: INSULATED DUAL WALL STAINLESS STEEL
Valve Lifters: HYDRAULIC ROLLER	Emissions Control: • CATALYTIC CONVERTER • AIR INJECTION REACTION (AIR) • POSITIVE CRANK CASE VENTILATION (PCV) • EXHAUST GAS RECIRCULATION (EGR) (F)	Main Bearing Caps: POWDER METAL
Firing Order: 1 - 8 - 7 - 2 - 6 - 5 - 4 - 3		Crankshaft: CAST IRON WITH UNDERCUT AND ROLLED FILLETS
		Camshaft: HOLLOW STEEL
		Connecting Rods: POWDER METAL
		Additional Features: EXTENDED LIFE SPARK PLUGS EXTENDED LIFE COOLANT OIL LEVEL SENSOR
		Applications: Chevrolet Corvette - base Chevrolet Camaro - option Pontiac Firebird - option
		Information may vary with application. All specifications listed are based on the latest product information available at the time of publication. The right is reserved to make changes at any time without notice.

__________________________________________________________________________________
Features and Benefits:
1998 F-CAR

Cylinder head - The LS1 features replicated ports to optimize air flow into the engine. This means that each cylinder head port is identical in every detail, and allows for very constant cylinder-to-cylinder airflow distribution. Better air flow means better performance for the customer. A four-bolt head and improved cylinder head fasteners reduce bore distortion, which in turn improve both fuel economy and emissions.

Intake manifold - The intake manifold is designed to provide capability to meet the performance, emissions and fuel economy requirements of the LS1. The LS1 intake manifold breathes better, thanks to use of new composite materials. The material is smoother and cooler, and allows air to glide with less restriction through the tubular thermoplastic intake manifold. This also enhances performance and reduces mass.

Valvetrain - The LS1 valvetrain offers customers some significant benefits in the areas of increased performance capability, fuel economy and noise reduction. Engineers designed a hollow camshaft to take mass out of the engine, based on the “lighter = faster” theory. The camshaft has larger bearing journals, which in turn, allows larger lobes; thereby, reducing lobe stress. In doing so, engineers have added the capability to design a more aggressive cam profile, which gains performance. Next, they’ve incorporated cast steel roller rocker arms. This adds stiffness to the valve train structure that reduces friction and enables higher speeds. You’ll also find hydraulic roller valve lifters that minimize friction and help eliminate internal power loss. They also maximize fuel economy and improve wear resistance over time.

Engine block - The LS1 has an aluminum block with a unique design. Engineers call it a “deep skirt” configuration because the block actually extends further down. This allows the main bearing caps to cross bolt into the block - six bolts per cap. This increases stiffness, and reduces crankshaft bending and, therefore, engine noise. Cast iron liners provide for durable cylinder bore wear. Also featured is a crankshaft with hollow main bearing journals - a definite improvement for mass as well as improved engine breathing. Improved breathing means that less energy is used “internal” to the engine, which in turn, leaves more horsepower available for the vehicle to improve performance.

Accessory drive - The system sets industry standards for quality, reliability and durability, and reductions in noise, vibration and contamination. Some enablers to achieve these goals are neat direct mount accessories; low static belt tension; slack side tensioner placement; dual track drive and the elimination of captured components, fasteners and wet attachment holes. Additionally, this system gives vehicle designers flexibility in packaging the powertrain.

Structural oil pan - The LS1 engine utilizes a structural aluminum oil pan which increases overall powertrain bending stiffness and allows 360 degree bolting to the transmission bell housing. This design increases the powertrain stiffness thereby reducing vibration. The oil pan-to-block sealing surface is a single plane allowing for the usage of a simple flat gasket, which will improve oil sealing quality and reliability.

Gerotor oil pump - The LS1 incorporates a high-efficiency gerotor oil pump, driven at the front of the crankshaft. It provides numerous customer benefits, such as improved low temperature oil delivery and better performance, due to less parasitic loss and improved pump efficiency.

Pistons - Another goal of the LS1 engine is emissions compliance well into the future. To that end, engineers have redesigned the piston with its top ring closer to the top of the piston to reduce hydrocarbon emissions. They also eased tension on the piston rings to reduce friction and improve fuel economy. LS1 pistons and rods are also very lightweight, which enables spinning of the engine at higher RPMs. This allows engineers to achieve more power from lower, more fuel efficient displacements.

Ignition system - Engineers have developed a new coil per cylinder ignition system. It features eight individual coils secured to two aluminum rocker covers. The coils themselves feature a composite material coil housing and integrated interface electronics to control the coil. The coil is located near the plug for high ignition energy, which results in increased combustion, better emissions and durability. The electronic spark timing signals for the coil are derived from crankshaft and camshaft position sensors to enable high accuracy spark delivery and misfire detection.

Powertrain Control Module (PCM) - The PCM for the LS1 engine is one of the industry’s most sophisticated. In fact, it may have more power than your home computer. It incorporates two custom integrated circuits. They include a multi-functional device that combines control functions for the fuel pump, linear EGR, and transmission line pressure control actuator output drivers into one package; and a new method to control engine knock, utilizing a digital signal to noise enhancement filter eliminating the plugin module and PCM access cover. Both are industry firsts. The “up-integration” of the features reduces mass and improves reliability by reducing the number of external wiring connections.

Exhaust manifold - The new design is significantly different from the conventional cast manifold. The right hand dual-wall fabricated manifold consists of two layers of high strength stainless steel, with an air gap in between. The thin inner wall heats up quickly, allowing rapid converter light off, thus reducing cold start emissions. The air gap helps as an insulator and this prevents the heat loss from the exhaust gas. This latest technology was selected primarily for its ability to aid in the reduction of cold start emissions by cutting down drastically on the time-to-temperature requirements. It dramatically improves the efficiency of the catalytic converter, maintaining at the same time, its ability to meet all other performance goals such as durability, enhanced performance and reduction of noise level. The air gap between the two layers of stainless steel helps to reduce the heat loss from he gas which in addition to helping meet the emissions goals, aids in reducing the underhood temperature. To further enhance the ability to reduce emissions, this dual wall manifold features integrated AIR passages. The left hand manifold incorporates a close-coupled converter therefore a single wall manifold is used.

Sequential Fuel Injection (SFI) - Enthusiasts understand the importance and benefits of SFI. The LS1 incorporates the most sophisticated use of this technology. SFI is a very precise fuel delivery system in which the powertrain control module (PCM) individually controls the fuel injectors. With SFI, each of the eight injectors are fired one at a time, in a sequence that matches the firing order, further improving fuel timing for optimal combustion. With SFI, the fuel is precisely metered, taking into account overall system pressure and temperature. SFI offers greater idle stability, performance, durability, fuel efficiency and driveability.

Other features - Other features of the LS1 that result in a variety of customer benefits include: powder metal connecting rods for improvements to fuel economy, emissions and pleasability; roller timing chain with nylon tensioners, also for improved pleasability; composite lifter restricters that decrease mass and increase fuel economy; dual electronic spark control sensor located in the valley of the block for increased spark control; integrated air fuel module for durability; and a mass air flow sensor to improve emissions.