Great info on the LE8 engine differances. I recieved this from a friend who works at Chevy in Spring Hill TN who I was requesting torture test reviews from.
2010 Ecotec 2.2L I-4 VVT ( LE8 )
ECOTEC 2.2L I-4 (LE8) TRUCK ENGINE
2010 Model Year Features and Benefits Summary
• Gen II Engine Block ( E85 Variant for Chevrolet HHR )
• Cylinder Head Improvements
• E37 Engine Control Module
• Piston features
• Oil Pump NVH improvement
• Front Cover enhancement
• Intake manifold
• E85 Flex Fuel
• Variable Valve Timing
• Split Catalytic Converter
Full Description of Features and Benefits for 2010 model year.
E85 Flex Fuel engine for 2010 Chevrolet HHR
The Ecotec 2.2L I-4 VVT (LE8) powers the Chevrolet HHR Panel and Passenger Van for 2010 model year. This Ecotec engine is installed transversely, and equipped with either a Hydra-Matic 4T45 (MN5) FWD automatic or a Getrag F23/5 (M86) manual transmission. Horsepower improvements of up to seven horsepower gain will be realized in these applications and consistent with all new GM engine rpo’s, the (LE8) will be SAE Certified for 2010 model year.
Gen II Engine Block
The Ecotec 2.2L starts with a refined engine block, introduced for 2006 with the Ecotec 2.4L I-4 VVT (RPO LE5). The Gen II block was developed with data acquired in racing programs and the latest math-based tools. Both the bore walls and bulkheads, or the structural elements that support the crank bearings, have been strengthened, with only a minimal weight increase (approximately 2.5 pounds). The coolant jackets have been expanded, allowing more precise bore roundness and improving the block’s ability to dissipate heat. Coolant capacity increases approximately .5 liter.
The cylinder block is the engine’s foundation, and crucial to its durability, output and smooth operation. For GM, the common Gen II Ecotec block increases assembly efficiency. For the customer, the result is more efficient cooling, more strength to accommodate additional power, and better noise, vibration and harshness control.
Cylinder Head Improvements
The Ecotec 2.2L VVT I-4 also benefits from cylinder head refinements introduced on the 2.4L VVT. The exhaust ports have been enlarged slightly to expel exhaust gas more efficiently. The improvements to the cylinder head increase Ecotec 2.2L horsepower slightly in most applications (see specs). A semi –permanent mold (SPM), casting process with improved material properties was selected for these new heads. Upgraded valve seats on both the intake and exhaust ports improve durability and enable the engine to run on E85 fuel. The LE8 has High Silicon Molybdenum cast nodular iron exhaust manifold, chosen for its durability and sound-deadening properties.
E37 Engine Control Module
New Piston Features
The 2010 LE8 pistons have valve pockets to allow full use of the variable cam phaser and an anodized upper ring groove for improved durability. The oil control ring has lower tension for reduced friction and the upper compression ring is made of a new, more durable material, compatible with E85 fuel.
Front Cover Enhancements
For 2010, all Ecotec engine front covers incorporate a more efficient “Goosehead" port oil pump design, reducing cavitation at higher engine speeds and results in a measurable reduction in noise at the customer's ear, especially in cold-start and drive-away operation. The oil pump also includes a pressure-balanced oil relief valve, further improving the durability and reliability of the lubrication system, as well as a lower friction crank seal.
Intake manifold
The (LE8) intake manifold features a LE5 style welded seam composite manifold which contributes to engine mass reduction and NVH improvements while maintaining the
improved flow characteristics for improved engine performance numbers.
E85 Flexible-Fuel Capability (LE8)
GM has led the industry in introducing flex-fuel capability to its cars and trucks, and the new flex-fuel 2.2L I-4 VVT ( LE8 ) extends availability to an even broader range of customers. E85 is a clean-burning alternative fuel made in the United States from corn and other crops, composed of 85 percent ethanol alcohol and 15 percent gasoline. The 2.2L’s flex-fuel technology is both sophisticated and durable.
Flex fuel engines require special valves and valve seats to withstand the wear and corrosive effects of ethanol. The nitrided Silcrome 1 intake valves and 21-43 exhaust valves used in the 2.2L I-4 are up to the challenge. Compared to conventional iron-alloy valve material, nitrided Silcrome 1 includes tungsten, vanadium, manganese, silicone and higher chromium content. It is harder, and it improves durability, even under the rigors of ethanol operation. The 21-43 exhaust valves work equally well. Valve seat inserts have been upgraded to premium materials with a high percent of tool steel and solid lubricants resulting in excellent durability whether E85 or gasoline is run in the engine.
Hardware changes for flex-fuel operation are limited to the injectors. Because ethanol has fewer BTUs (less energy) than the same volume of gasoline, more fuel is required to produce the same horsepower at wide-open throttle. Flex fuel engines use unique stainless injectors with a greater cone angle and higher maximum fuel-flow rate. The fuel rail matches the injectors, but it’s manufactured of the same stainless steel used for all 2.2L I-4 fuel rails.
The flex-fuel 2.2L doesn’t require a special fuel sensor. The first flex-fuel engines used a light-reactive sensor to measure fuel composition from 100 percent gasoline to 85 percent ethanol. The 2.2L has a virtual sensor—software programmed in the E37 ECM with no separate physical sensor whatsoever. Based on readings from the oxygen (O2) sensors, fuel level sensor and vehicle speed sensors, the ECM adjusts the length of time the fuel injectors open for the type of fuel used. Within a few miles after filling up, the E37 controller determines what fuel is powering the 2.2L I-4 and manages the engine accordingly.
Variable Valve Timing
Variable Valve Timing (VVT) is included in these applications, and allows the powertrain system to take advantage of dual independent continuously variable valve timing for greater efficiency. Dual Independent VVT eliminates the compromise inherent in conventional fixed valve timing and allows a previously unattainable mix of low-rpm torque, even torque delivery over a broad range of engines speeds, and free-breathing high-rev horsepower.
The dual-independent cam phasers adjust intake and exhaust camshaft timing independent from one another for both intake and exhaust valves. A vane-type phaser is installed on the cam sprocket of both the intake and exhaust camshafts to turn these camshafts relative to the sprockets, thereby adjusting the timing of the valve operation. The vane phaser is actuated by hydraulic pressure from engine oil, and managed by a solenoid that controls oil pressure on the phaser. The phaser uses a wheel or rotor with five vanes (like a propeller) to turn the camshaft relative to the cam sprocket, which turns at a fixed rate via chain from the crankshaft. The solenoid directs oil to pressure ports on either side of the five phaser vanes; the vanes, and camshaft, turn as directed by this pressure. The more pressure, the more the phaser and camshaft turn. The engine control module directs the phaser to advance or retard cam timing, depending on driving demands. The dual-independent phasers can turn their respective camshafts over a range of 25 degrees relative to the cam sprocket, or 50 cam degrees from their parked positions.
The benefits are considerable. The cam phasers change valve timing on the fly, maximizing engine performance for given demands and conditions. At idle, for example, the intake cam is retarded and the exhaust cam is advanced which minimizes valve overlap, and allows for exceptionally smooth idling. Under other operating demands, the phasers adjust to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm, the intake phaser might retard intake timing to maximize airflow through the engine and increase horsepower. At low rpm, the intake phaser advances to increase torque. Under a light load (say, casual everyday driving), the phasers are calibrated to select the optimum valve centerlines to maximize fuel economy. Without cam phasing, a cam design and valve timing must be biased toward one strength or another—high-end horsepower or low-end torque, for example—or profiled at some median level that maximizes neither.
The cam phaser is timed to hold the intake valve open a short time longer than a normal engine, allowing a reverse flow into the intake manifold. This reduces the effective compression ratio, allowing the expansion ratio to increase while retaining normal combustion pressures. Efficiency is gained because the high expansion ratio delivers a longer power stroke and reduces the heat wasted in the exhaust. This increase in efficiency comes at the expense of some power from the lower effective compression ratio, but that can be compensated for by the overall higher mechanical compression ratio.
Variable valve timing allows linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or drivability. It also provides another effective tool for controlling exhaust emissions because it manages valve overlap at optimum levels.
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