New Era in Small Block Performance Launches with Gen 5
10-29-2012, 07:16 PM
#1
New Era in Small Block Performance Launches with Gen 5
Next Corvette’s LT1 V-8 brings more power, new opportunities for builders and tuners
LAS VEGAS – The Small Block V-8 became a staple of the performance industry about five minutes after it debuted in production vehicles in 1955. Nearly 60 years later it remains the hot rod engine of choice for the majority of builders, whether they’re using a classic Gen 1 “350” or a late-model “LS” engine.
A new era in Small Block performance launches next year with the Gen 5 engine, which debuts in the next Corvette with the historic LT1 name. With preliminary output of 450 horses (335 kW), it will be the most powerful standard engine ever in the Corvette – the result of complete reengineering for superior performance and efficiency. It’s the most significant redesign of the Small Block in its nearly 60-year history.
The new, LT1 6.2L (376 cubic inches) retains the 4.40-inch bore center specification that has defined the Small Block architecture since its introduction – along with the compact size that enables great design flexibility in a sleek sports car such as the Corvette. It also uses a trio of Next-Gen technologies, including direct injection, Active Fuel Management and variable valve timing, to support an advanced combustion system, to deliver more power with greater efficiency. It marks the first time direct injection has been employed on the Small Block architecture and the first time all of the technologies have been used on the Corvette.
The new technologies and features of the Gen 5 are comprehensively different when compared with the Gen IV Small Block – from a camshaft with an additional lobe to drive the direct injection system’s fuel pump to an all-new cylinder head design and variable-displacement oil pump. The Gen 5 is also directed by a new “E92” controller.
“The Gen 5 Small Block represents a new chapter in the Small Block’s history and a new opportunity for the performance industry and builders,” said Jim Campbell, GM U.S. vice president of Performance Vehicles & Motorsports. “Some of its features, including the direct injection system and a new cylinder head design to support the advanced combustion system, will provide additional opportunities for the performance community. I’m sure it won’t be long after it debuts that higher-performance LT1s will be hitting the streets and tracks everywhere.”
Highlights and features of the LT1 include:
New aluminum cylinder block casting with nodular main bearing caps
Engine-driven fuel pump mounted in the valley beneath the intake manifold
Camshaft with new “tri-lobe” design to drive the fuel pump
All-new piston head design to support direct injection
11.5:1 compression ratio
Variable-displacement vane-type oil pump
Available dry-sump oiling system
Oil-spray piston cooling
Rocker covers with integral PCV system
“Four-into-one” exhaust manifolds
“Runners in a box” intake manifold design with 87mm throttle body
Redesigned cooling system with offset water pump and thermostat
Maximum engine speed of 6,600 rpm.
“Builders and the aftermarket manufacturers embraced the LS engine family,” said Campbell. “It will be exciting to see how the industry demonstrates its proven record of innovation and creativity with the Gen 5.”
General Motors’ investment in the Gen 5 Small Block will create or retain more than 1,600 jobs in five North American plants, including Tonawanda, New York, which recently received upgrades to support its production.
Next-Gen technologies
The key to the LT1’s more powerful, more efficient performance is its trio of Next-Gen technologies: direct injection, Active Fuel Management and variable valve timing. They work together and complement the engine’s supporting technologies to optimize combustion efficiency across the rpm band, delivering great low-end torque and excellent high-rpm horsepower – all with lower emissions than previous Small Block engines.
Direct injection is all-new to the Small Block architecture and is a primary contributor to the Gen 5’s greater combustion efficiency, because it fosters a more complete burn of the fuel in the air-fuel mixture. Direct injection keeps the combustion chamber cooler, allowing a higher compression ratio – which supports greater power – and improved combustion efficiency. It also delivers reduced emissions, particularly cold-start hydrocarbon emissions, which are cut by about 25 percent.
Active Fuel Management (AFM) – it’s first-ever application on the Corvette – helps save fuel by shutting down half of the engine’s cylinders in light-load driving. Additionally, the variable valve timing system that GM pioneered for overhead-valve engines is refined to support the Gen 5’s AFM and direct injection systems to optimize performance, efficiency and emissions.
Advanced combustion system
Introducing direct injection to the Small Block necessitated an all-new, advanced combustion system, which includes a new cylinder-head design and new, dished piston design. They work cohesively to exploit the high-compression, mixture motion parameters enabled by direct injection.
The Gen 5 head features a smaller combustion chamber designed to complement the volume of the dish on each of the pistons’ heads. The smaller chamber size and dished pistons produce an 11.5:1 compression ratio, while the head features large, straight and rectangular intake ports with a slight twist to enhance mixture motion. This is complemented by a reversal of the intake and exhaust valve positions, as compared to the Gen IV design. Also, the spark plug angle and depth have been revised to protrude farther into the chamber, placing the electrode closer to the center of the combustion to support the direct injection system.
The pistons feature dished heads and “risers” at the top designed to direct the fuel spray for a more complete combustion. The contours of the multi-plane piston heads are machined to ensure dimensional accuracy – essential for delivering the correct combustion ratio – and enhance strength.
Cylinder block and oiling system
The Gen 5 block is an all-new casting, but retains the deep-skirt design introduced on the Gen 3 and carried over to the Gen 4 Small Blocks. It also retains the six-bolt, cross-bolted main-bearing caps that limit crank flex and stiffen the engine’s structure. A structural aluminum oil pan further stiffens the powertrain.
The new block features nodular iron main caps, which represent a significant upgrade over more conventional powdered metal bearing caps. They are stronger and can better absorb vibrations and other harmonics to help produce smoother, quieter performance.
The Gen 5’s oiling system – including standard oil-spray piston cooling – supports the NexGen advanced technologies. It is driven by a new, variable-displacement oil pump that enables more efficient oil delivery, per the engine’s operating conditions. Its dual-pressure control enables operation at a very efficient oil pressure at lower rpm coordinated with the Active Fuel Management and operation at a higher pressure at higher engine speeds providing a more robust lube system with aggressive engine operation.
Standard oil-spray piston cooling drenches the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, friction-reducing oil via small jets located at the bottom of the cylinders.
An available dry-sump oiling system promotes exceptional lubrication system performance during extended high-rpm use under high cornering loads. It includes two stages of oil pumping, including the new, dual-pressure-control and variable-displacement vane pump and a scavenge pump.
Dexos semi-synthetic motor oil, including a 5W30 specification that helps reduce friction to enhance the LT1’s efficiency.
Supporting technologies and components
Tri-lobe camshaft: Compared to the Gen IV Small Block, the camshaft remains in the same position relative to the crankshaft and is used with a new rear cam bearing, but it features an all-new “tri-lobe” design to drive the engine-mounted, high-pressure fuel pump for the direct-injection combustion system. The cam’s specifications include 14mm/13.3mm (0.551/0.524-inch) intake/exhaust lift, 200/207-crank angle degrees intake/exhaust duration at 0.050-inch tappet lift and a 116.5-degree cam angle lobe separation.
Cam-driven fuel pump: The direct injection system features very high fuel pressure, up to 15Mpa (150bar), requiring a high-pressure, engine-driven fuel pump in addition to a conventional, fuel-tank-mounted pump. It is mounted in the “valley” between cylinder heads – beneath the intake manifold. It is driven by the camshaft at the rear of the engine.
PCV-integrated rocker covers: One of the most distinctive features of the all-new Gen 5 engine is its domed rocker covers, which house a patent-pending integrated positive crankcase ventilation (PCV) system that enhances oil economy and oil life, while reducing oil consumption and contributing to low emissions. The rocker covers also hold the direct-mount ignition coils for the coil-near-plug ignition system. Between the individual coil packs, the domed sections of the covers contain baffles that separate oil and air from the crankcase gases – about three times the oil/air separation capability of previous engines.
Intake manifold and throttle body assembly: The LT1’s intake manifold features a “runners in a box” design, wherein individual runners inside the manifold feed a plenum box that allows for excellent, high-volume airflow packaged beneath the car’s low hood line. The ports are designed to match cylinder head, while also accommodating the high-pressure fuel pump for the direct injection system, which is mounted in the valley area between the cylinder heads.
The manifold is paired with an electronically controlled throttle, featuring an 87mm bore diameter and a “contactless” design that is more durable and enables greater control.
Four-into-one exhaust manifolds: The LT1 uses a similar yet cast version of the “four-into-one” short-header exhaust manifold design used on the Gen 4 LS7 engine. The cast header passages enable consistent exhaust flow into the “wide mouth” collector at the converter.
Cooling system, humidity sensor and more: Additional features and technologies of the Gen 5 Small Block include:
A revised cooling system with and offset water pump and thermostat for more efficient performance
Air induction humidity sensor ensures optimal combustion efficiency, regardless of the surrounding air’s humidity
58X ignition system with individual coil-on-plug modules and iridium-tip spark plugs
All-new “E92” engine controller.
The Small Block V-8 debuted in the Corvette in 1955, when it displaced 4.3L (265 cubic inches) and was rated at 195 horsepower, drawing air and fuel through a four-barrel carburetor. In comparison, the power-dense Gen 5 LT1 engine, which uses the same cam-in-block architecture with 4.40-inch bore centers as the original Small Block, produces 231 percent more power from only 42-percent larger displacement.
Gen 5 Small Block (LT1) Specifications
Engine type: 90-degree V-8 with overhead valves; continuous VVT
Displacement: 6.2L (376 cubic inches)
Bore x Stroke (in / mm): 4.06 x 3.62 / 103.25 x 92
Cylinder block: cast aluminum with nodular main caps
Main bearing fasteners: six, including two cross-bolts per cap
Crankshaft: forged steel
Connecting rods: powder metal, 6.125 inches in length
Pistons: eutectic aluminum alloy
Compression ratio: 11.5:1
Cylinder heads: 319-T7 cast aluminum with 59.02cc combustion chambers
Valve angles (degrees): 12.5 intake, 12 exhaust
Intake valves: 2.13 inches (54mm) hollow
Exhaust valves: 1.59 inches (40.4mm) hollow sodium
Camshaft: Hydraulic-type with tri-lobe for fuel-pump drive
Camshaft lift: 0.551-inch (14mm) intake / 0.524-inch (13.3mm) exhaust
Camshaft duration: 200-degrees intake / 207-degrees exhaust (at 0.050-inch)
Lobe separation angle: 116.5 degrees
Fuel delivery: direct injection
Intake manifold: “runners in a box” design; composite construction
Throttle: 87mm electronically controlled throttle body
Ignition: 58X with individual coil-on-plug and iridium-tip spark plugs
Horsepower / kW: 450 / 335 (estimated)
Torque – lb.-ft. / Nm: 450 / 610 (estimated)
Max. engine speed 6,600 rpm (fuel cutoff)
Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 140 countries and selling more than 4 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature spirited performance, expressive design and high quality. More information on Chevrolet models can be found at 2013 Chevy Cars, Trucks, SUVs, Crossovers and Vans | Chevrolet.
LAS VEGAS – The Small Block V-8 became a staple of the performance industry about five minutes after it debuted in production vehicles in 1955. Nearly 60 years later it remains the hot rod engine of choice for the majority of builders, whether they’re using a classic Gen 1 “350” or a late-model “LS” engine.
A new era in Small Block performance launches next year with the Gen 5 engine, which debuts in the next Corvette with the historic LT1 name. With preliminary output of 450 horses (335 kW), it will be the most powerful standard engine ever in the Corvette – the result of complete reengineering for superior performance and efficiency. It’s the most significant redesign of the Small Block in its nearly 60-year history.
The new, LT1 6.2L (376 cubic inches) retains the 4.40-inch bore center specification that has defined the Small Block architecture since its introduction – along with the compact size that enables great design flexibility in a sleek sports car such as the Corvette. It also uses a trio of Next-Gen technologies, including direct injection, Active Fuel Management and variable valve timing, to support an advanced combustion system, to deliver more power with greater efficiency. It marks the first time direct injection has been employed on the Small Block architecture and the first time all of the technologies have been used on the Corvette.
The new technologies and features of the Gen 5 are comprehensively different when compared with the Gen IV Small Block – from a camshaft with an additional lobe to drive the direct injection system’s fuel pump to an all-new cylinder head design and variable-displacement oil pump. The Gen 5 is also directed by a new “E92” controller.
“The Gen 5 Small Block represents a new chapter in the Small Block’s history and a new opportunity for the performance industry and builders,” said Jim Campbell, GM U.S. vice president of Performance Vehicles & Motorsports. “Some of its features, including the direct injection system and a new cylinder head design to support the advanced combustion system, will provide additional opportunities for the performance community. I’m sure it won’t be long after it debuts that higher-performance LT1s will be hitting the streets and tracks everywhere.”
Highlights and features of the LT1 include:
New aluminum cylinder block casting with nodular main bearing caps
Engine-driven fuel pump mounted in the valley beneath the intake manifold
Camshaft with new “tri-lobe” design to drive the fuel pump
All-new piston head design to support direct injection
11.5:1 compression ratio
Variable-displacement vane-type oil pump
Available dry-sump oiling system
Oil-spray piston cooling
Rocker covers with integral PCV system
“Four-into-one” exhaust manifolds
“Runners in a box” intake manifold design with 87mm throttle body
Redesigned cooling system with offset water pump and thermostat
Maximum engine speed of 6,600 rpm.
“Builders and the aftermarket manufacturers embraced the LS engine family,” said Campbell. “It will be exciting to see how the industry demonstrates its proven record of innovation and creativity with the Gen 5.”
General Motors’ investment in the Gen 5 Small Block will create or retain more than 1,600 jobs in five North American plants, including Tonawanda, New York, which recently received upgrades to support its production.
Next-Gen technologies
The key to the LT1’s more powerful, more efficient performance is its trio of Next-Gen technologies: direct injection, Active Fuel Management and variable valve timing. They work together and complement the engine’s supporting technologies to optimize combustion efficiency across the rpm band, delivering great low-end torque and excellent high-rpm horsepower – all with lower emissions than previous Small Block engines.
Direct injection is all-new to the Small Block architecture and is a primary contributor to the Gen 5’s greater combustion efficiency, because it fosters a more complete burn of the fuel in the air-fuel mixture. Direct injection keeps the combustion chamber cooler, allowing a higher compression ratio – which supports greater power – and improved combustion efficiency. It also delivers reduced emissions, particularly cold-start hydrocarbon emissions, which are cut by about 25 percent.
Active Fuel Management (AFM) – it’s first-ever application on the Corvette – helps save fuel by shutting down half of the engine’s cylinders in light-load driving. Additionally, the variable valve timing system that GM pioneered for overhead-valve engines is refined to support the Gen 5’s AFM and direct injection systems to optimize performance, efficiency and emissions.
Advanced combustion system
Introducing direct injection to the Small Block necessitated an all-new, advanced combustion system, which includes a new cylinder-head design and new, dished piston design. They work cohesively to exploit the high-compression, mixture motion parameters enabled by direct injection.
The Gen 5 head features a smaller combustion chamber designed to complement the volume of the dish on each of the pistons’ heads. The smaller chamber size and dished pistons produce an 11.5:1 compression ratio, while the head features large, straight and rectangular intake ports with a slight twist to enhance mixture motion. This is complemented by a reversal of the intake and exhaust valve positions, as compared to the Gen IV design. Also, the spark plug angle and depth have been revised to protrude farther into the chamber, placing the electrode closer to the center of the combustion to support the direct injection system.
The pistons feature dished heads and “risers” at the top designed to direct the fuel spray for a more complete combustion. The contours of the multi-plane piston heads are machined to ensure dimensional accuracy – essential for delivering the correct combustion ratio – and enhance strength.
Cylinder block and oiling system
The Gen 5 block is an all-new casting, but retains the deep-skirt design introduced on the Gen 3 and carried over to the Gen 4 Small Blocks. It also retains the six-bolt, cross-bolted main-bearing caps that limit crank flex and stiffen the engine’s structure. A structural aluminum oil pan further stiffens the powertrain.
The new block features nodular iron main caps, which represent a significant upgrade over more conventional powdered metal bearing caps. They are stronger and can better absorb vibrations and other harmonics to help produce smoother, quieter performance.
The Gen 5’s oiling system – including standard oil-spray piston cooling – supports the NexGen advanced technologies. It is driven by a new, variable-displacement oil pump that enables more efficient oil delivery, per the engine’s operating conditions. Its dual-pressure control enables operation at a very efficient oil pressure at lower rpm coordinated with the Active Fuel Management and operation at a higher pressure at higher engine speeds providing a more robust lube system with aggressive engine operation.
Standard oil-spray piston cooling drenches the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, friction-reducing oil via small jets located at the bottom of the cylinders.
An available dry-sump oiling system promotes exceptional lubrication system performance during extended high-rpm use under high cornering loads. It includes two stages of oil pumping, including the new, dual-pressure-control and variable-displacement vane pump and a scavenge pump.
Dexos semi-synthetic motor oil, including a 5W30 specification that helps reduce friction to enhance the LT1’s efficiency.
Supporting technologies and components
Tri-lobe camshaft: Compared to the Gen IV Small Block, the camshaft remains in the same position relative to the crankshaft and is used with a new rear cam bearing, but it features an all-new “tri-lobe” design to drive the engine-mounted, high-pressure fuel pump for the direct-injection combustion system. The cam’s specifications include 14mm/13.3mm (0.551/0.524-inch) intake/exhaust lift, 200/207-crank angle degrees intake/exhaust duration at 0.050-inch tappet lift and a 116.5-degree cam angle lobe separation.
Cam-driven fuel pump: The direct injection system features very high fuel pressure, up to 15Mpa (150bar), requiring a high-pressure, engine-driven fuel pump in addition to a conventional, fuel-tank-mounted pump. It is mounted in the “valley” between cylinder heads – beneath the intake manifold. It is driven by the camshaft at the rear of the engine.
PCV-integrated rocker covers: One of the most distinctive features of the all-new Gen 5 engine is its domed rocker covers, which house a patent-pending integrated positive crankcase ventilation (PCV) system that enhances oil economy and oil life, while reducing oil consumption and contributing to low emissions. The rocker covers also hold the direct-mount ignition coils for the coil-near-plug ignition system. Between the individual coil packs, the domed sections of the covers contain baffles that separate oil and air from the crankcase gases – about three times the oil/air separation capability of previous engines.
Intake manifold and throttle body assembly: The LT1’s intake manifold features a “runners in a box” design, wherein individual runners inside the manifold feed a plenum box that allows for excellent, high-volume airflow packaged beneath the car’s low hood line. The ports are designed to match cylinder head, while also accommodating the high-pressure fuel pump for the direct injection system, which is mounted in the valley area between the cylinder heads.
The manifold is paired with an electronically controlled throttle, featuring an 87mm bore diameter and a “contactless” design that is more durable and enables greater control.
Four-into-one exhaust manifolds: The LT1 uses a similar yet cast version of the “four-into-one” short-header exhaust manifold design used on the Gen 4 LS7 engine. The cast header passages enable consistent exhaust flow into the “wide mouth” collector at the converter.
Cooling system, humidity sensor and more: Additional features and technologies of the Gen 5 Small Block include:
A revised cooling system with and offset water pump and thermostat for more efficient performance
Air induction humidity sensor ensures optimal combustion efficiency, regardless of the surrounding air’s humidity
58X ignition system with individual coil-on-plug modules and iridium-tip spark plugs
All-new “E92” engine controller.
The Small Block V-8 debuted in the Corvette in 1955, when it displaced 4.3L (265 cubic inches) and was rated at 195 horsepower, drawing air and fuel through a four-barrel carburetor. In comparison, the power-dense Gen 5 LT1 engine, which uses the same cam-in-block architecture with 4.40-inch bore centers as the original Small Block, produces 231 percent more power from only 42-percent larger displacement.
Gen 5 Small Block (LT1) Specifications
Engine type: 90-degree V-8 with overhead valves; continuous VVT
Displacement: 6.2L (376 cubic inches)
Bore x Stroke (in / mm): 4.06 x 3.62 / 103.25 x 92
Cylinder block: cast aluminum with nodular main caps
Main bearing fasteners: six, including two cross-bolts per cap
Crankshaft: forged steel
Connecting rods: powder metal, 6.125 inches in length
Pistons: eutectic aluminum alloy
Compression ratio: 11.5:1
Cylinder heads: 319-T7 cast aluminum with 59.02cc combustion chambers
Valve angles (degrees): 12.5 intake, 12 exhaust
Intake valves: 2.13 inches (54mm) hollow
Exhaust valves: 1.59 inches (40.4mm) hollow sodium
Camshaft: Hydraulic-type with tri-lobe for fuel-pump drive
Camshaft lift: 0.551-inch (14mm) intake / 0.524-inch (13.3mm) exhaust
Camshaft duration: 200-degrees intake / 207-degrees exhaust (at 0.050-inch)
Lobe separation angle: 116.5 degrees
Fuel delivery: direct injection
Intake manifold: “runners in a box” design; composite construction
Throttle: 87mm electronically controlled throttle body
Ignition: 58X with individual coil-on-plug and iridium-tip spark plugs
Horsepower / kW: 450 / 335 (estimated)
Torque – lb.-ft. / Nm: 450 / 610 (estimated)
Max. engine speed 6,600 rpm (fuel cutoff)
Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 140 countries and selling more than 4 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature spirited performance, expressive design and high quality. More information on Chevrolet models can be found at 2013 Chevy Cars, Trucks, SUVs, Crossovers and Vans | Chevrolet.
10-30-2012, 11:54 AM
#2
Registered User
Join Date: Jul 2004
Posts: 324
Re: New Era in Small Block Performance Launches with Gen 5
Are the ECU going to be harder to custom tune? I heard they had similar encryption as those on Chryslers, and would be difficult and expensive to "crack" for tuners.
10-30-2012, 06:36 PM
#3
Registered User
Join Date: Oct 2003
Location: Jupiter, FL
Posts: 1,647
Re: New Era in Small Block Performance Launches with Gen 5
Next Corvette’s LT1 V-8 brings more power, new opportunities for builders and tuners...
“The Gen 5 Small Block represents a new chapter in the Small Block’s history and a new opportunity for the performance industry and builders,” said Jim Campbell, GM U.S. vice president of Performance Vehicles & Motorsports. “Some of its features, including the direct injection system and a new cylinder head design to support the advanced combustion system, will provide additional opportunities for the performance community. I’m sure it won’t be long after it debuts that higher-performance LT1s will be hitting the streets and tracks everywhere.”
“The Gen 5 Small Block represents a new chapter in the Small Block’s history and a new opportunity for the performance industry and builders,” said Jim Campbell, GM U.S. vice president of Performance Vehicles & Motorsports. “Some of its features, including the direct injection system and a new cylinder head design to support the advanced combustion system, will provide additional opportunities for the performance community. I’m sure it won’t be long after it debuts that higher-performance LT1s will be hitting the streets and tracks everywhere.”
10-31-2012, 10:23 PM
#5
Registered User
Join Date: Jun 2004
Location: SeVa
Posts: 2,977
Re: New Era in Small Block Performance Launches with Gen 5
PCV-integrated rocker covers: One of the most distinctive features of the all-new Gen 5 engine is its domed rocker covers, which house a patent-pending integrated positive crankcase ventilation (PCV) system that enhances oil economy and oil life, while reducing oil consumption and contributing to low emissions. The rocker covers also hold the direct-mount ignition coils for the coil-near-plug ignition system. Between the individual coil packs, the domed sections of the covers contain baffles that separate oil and air from the crankcase gases – about three times the oil/air separation capability of previous engines
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