|11-06-2007, 12:25 PM||#1|
I used to be Dragoneye...
LS3 Specs, and Descriptions
The following items are official GM released specs, pictures, and descriptions of the latest iteration of the legendary Small-block, the LS3.
Please Note, that this engine HAS NOT been decided on as a motor for the new 5th generation Camaro. However it is a contender, which is why this motherload of information has been created.
|11-06-2007, 12:35 PM||#2|
I used to be Dragoneye...
2008 “LS3” 6.2L V8 (LS3)
6.2L V8 (LS3) CAR ENGINE
Description of New and Update Features
· Displacement increase to 6.2L from the 6.0L LS2
· Performance enhancement from base Corvette LS2
· SAE Certified Power & Torque
· Horsepower increase from 400 to 430
· Torque increase from 400 to 424 lb.ft.
· Additional +6 Hp increase with optional active exhaust system
For 2008, General Motors Powertrain engineers have again added a performance kick to the Corvette base engine with introduction of the new LS3 6.2L engine which replaces the LS2. The 2008 6.2L LS3 V8 with 430 Hp @ 5900 rpm and 424 lb.ft. torque @ 4600 rpm is the most powerful Corvette base engine ever and is SAE Certified for 2008 model year.
The LS3 engineering team focused on design elements to increase flow efficiency in addition to the displacement increase to meet the performance enhancement. The bore was increased to a larger 103.25 mm diameter compared to the LS2 bore of 101.6. Engine stroke remains at 92.0mm. Intake flow efficiency was optimized by straightening out and optimizing the flow path from the intake manifold into the cylinder heads. A high flow efficiency induction system is borrowed from the Z06 application. The cylinder head exhaust ports have been modified to increase flow. Also now available in the Corvette with the LS3 is a butterfly valve in the exhaust system which opens at high exhaust flow levels and by-passes the “tri-flow” S-shaped path the exhaust gases normally follow. This reduces exhaust restriction, yet allows the Corvette LS3 to hum at a more muted burble during part-throttle operation. The LS3 also meets the more stringent Bin4 emission standards and again avoids the gas guzzler tax. The small block tradition of more for less continues.
High Flow Cylinder Heads
The intake port shape size and shape have been modified to increase flow. The higher flow intake ports are similar to the L92 6.2L. Casting changes were made to increase the opening at the exhaust face to improve exhaust port flow. A new exhaust manifold opening is required to match the heads.
The inlet rocker arm is offset 6 mm between the valve tip and rocker bolt/push rod to enable a more direct intake port. The intake valve diameter is increased from 50.8 to 55.0 mm. Hollow stem intake were implemented to enable the 6600 rpm capability (13% reduction in mass from LS2). The 40.4 mm diameter exhaust valves are carried over from L92. Carryover LS2 high load valve springs are also included for 6600 rpm capability. Intake lift increases from 13.25mm to 14.0mm. Exhaust lobes are carryover LS2. Camshaft timing is revised.
Higher flow intake manifold with acoustic shell
Intake ports revised to match new cylinder head. The new composite intake manifold is manufactured with a lost core process to improve runner to runner variation and to reduce flow losses. Acoustic foam is sandwiched between the outside top of the intake manifold and an additional “skull cap” acoustic shell to reduce radiated engine noise. Structural enhancements have been added to the manifold bosses.
Larger bore block with structural improvements
Casting and machining in the bulkheads was revised to improve block structure and to improve bay to bay breathing. The enhanced cylinder block is shared with the the 6.2L truck applications.
A new larger diameter piston design is introduced for which includes design enhancements for the higher engine output.
Higher Flow Injectors
Higher flow 5.0 g/s injectors were used from the LS7 engine.
New Acoustic / Beauty Cover
The new beauty cover has a revised appearance and new acoustic treatment
|11-06-2007, 12:51 PM||#4|
I used to be Dragoneye...
2008 "LS3" 6.2L V8 (LS3) Car
Type:......................................6.2L Gen IV V8
Small BlockDisplacement:........6162cc (376.0 ci)
Valve configuration:..................overhead valves (2 valves per cylinder)
Assembly site:........................St. Catharines, Ontario
Valve lifters: ...........................hydraulic roller
Firing order: ...........................1 - 8 - 7 - 2 - 6 - 5 - 4 - 3
Bore x stroke:.........................103.25 x 92mm
Fuel system: .........................sequential fuel injection
Fuel type:...............................premium fuel recommended
Valves per cylinder:.................2
Bore Center (mm):..................111.76
Fuel shut off:..........................6600 rpm
Emissions controls:................catalytic converterthree-way catalystpositive crankcase ventilation
Applications: hp ( kw )/Torque ( Nm )
430(321kW) @ 5900 / 424(575Nm) @ 4600 SAE CERTIFIED
Chevrolet Corvette w/ Optional Exhaust:
436(325kW) @ 5900 / 428(580Nm) @ 4600 SAE CERTIFIED
Cylinder head:...........cast aluminum
Intake manifold: ........composite
Exhaust manifold:......cast nodular iron
Main bearing caps:.....powder metal
Crankshaft:................cast iron with undercut and rolled fillets
Connecting rods:.......forged powder metal
...........................extended life spark plugs
...........................extended life coolant
...........................oil level sensor
...........................Oil Life System
|11-06-2007, 01:04 PM||#6|
I used to be Dragoneye...
GM's 436-horse LS3
by Tony Whatley
Being a GM enthusiast, there is no doubt that you have been exposed to the buzz going on about the upcoming 2008 updates to the base model Corvette. With the 1997 introduction of the LSX-series engines, GM has continued to raise the bar every few years when it didn't seem possible to do so. The 5.7L LS1 debuted with a rating of 345hp. Then along came the 6.0L LS2 in 2005 to bring the Corvette 400hp under the hood. For 2008, we now have the new 6.2L LS3 engine: SAE rated to 436hp and 428lb-ft of torque! This provides enough motivation for the 2008 Corvette to reach 190-mph top speeds, which makes it the fastest base-model Corvette ever produced.
The LS3 is still considered the GM Generation IV architecture small-block, and it shows a nice progression from the LS2, which it replaces. The new engine block is the same as the 6.2L L92 aluminum blocks found in the 2007 Escalade and Denali trucks. It has the typical cast-in iron cylinder sleeves, but the bore diameter has increased from the previous LS2's 4.00 inches up to 4.06 inches, which results in a displacement increase from 6.0L to 6.2L. Some casting and machining updates were made with the LS3/L92 block, resulting in 20% stronger bulkheads inside. It is interesting to note that all of the base model Corvette LSX engines have shared the same crankshaft stroke of 3.62 inches, and this remains with the LS3. By using some simple hot-rodder math, readers have probably figured out that these 4.06-inch cylinder bores can be used to build some relatively inexpensive 414ci stroker engines by just swapping in a 4.00-inch rotating assembly. Looking back in the LSX world a few years ago, it would have required costly resleeving of the 3.90-inch bore LS1 blocks to achieve displacements beyond 382 ci. Needless to say, the GM performance aftermarket loves the parts GM now offers over the counter.
Inside of the block, we find newly designed flat-top pistons with coated side skirts. These hypereutectic cast-aluminum pistons help bring the compression ratio to a pump-gas-friendly 10.7:1. The piston oil control rings have revised tension to handle the higher 6,600 rpm redline. Even the piston profile and pin bore were revised to reduce engine noise and vibration. The pistons use a new pin that is taper-bored to reduce mass. At the big end of the connecting rods, the bolts have been upgraded to 12.9-grade material, similar to what is used in the 505hp LS7.
GM also decided to use a slightly more agressive camshaft in the LS3. The intake lift has increased from 0.521 inch found in the LS2 to 0.551 inch for the LS3. Slightly less overlap was also used for the LS3 cam.
The biggest change between the LS2 and the LS3 is the introduction of rectangle port cylinder heads, which replace the popular "cathedral" port shape of the LSX head family. The LS3 borrows this performace technology from the C5-R and C6.R Corvette racing programs, where similar intake ports were developed and have dominated the race circuits. Rectangle ports first appeared on the 7.0L LS7 found in the 2006 Z06, and have now trickled down to little brother. This is definitely not a hand-me-down to complain about!
The intake port entrance is similar in design compared to the LS7 head, but the location and size of the ports are different enough to require LS3 specific intake maniforlds. The aluminum LS3 cylinder head castings are also shared with the L92 truck engines, mentioned above. Although the castings on the LS3/L92 are the same, the valvetrain is upgraded on the LS3 to handle higher rpm. Lightweight hollow-stem valves are used, along with LS6 valvesprings that can handle the higher intake lift found in the LS3 camshaft. The intake valve diameter has increased from 2.00 inches found in the LS2 to 2.16 inches for the LS3. Exhaust valve diameter has increased to 1.60 inches from 1.55 inches. In order to make room for the rectangle ports and the larger valve sizes, the rocker arms had to be offset 6mm from center on the intake side. The exhaust side rockers remain unchanged from the previous LS2 design. All of these changes result in cylinder heads that flow over 17% more at the same peak flow lift of the previous LS2 casting, and they continue flowing at higher lifts where the LS2 port would stall.
One item that isn't shared with the GM truck parts bin is the newly designed LS3 intake manifold. GM uses a lost-core process to manufacture the new composite plastic intake manifold. One unique development is a layer of sound insulation foam, contained inside of an area between the internal air runners and the external top shell. This results in less valvetrain and high-frequency noise transmitted to the passengers. Even the typical Corvette fuel rail beauty covers now have acoustic dampening material added underneath to reduce engine noise. Initial tests show the new SL3 intake design flows much more than the LS2 intake, but also does so with 2% less internal restriction. The fuel rail is identical to the LS2 fuel rail, but now LS7 fuel injectors are used to handle the power increase. The same 90mm diameter, four-bolt mounting-style throttle body is carried over from the LS2.
The most interesting aspect of these LS3 enhancements isn't how well they perform right off the dealer showroom, it is their potential in the modified engine aftermarket. The flow numbers seen from these LS3/L92 cylinder heads are only scratching the surface of potential when in factory form. The larger bore cylinders only make it easier to build more reliable and inexpensive stroker engines. The newer intake manifold is an impovement over the popular LS6 intake manifold bottleneck. Engine builders are using these heads and blocks to produce beasts making 700hp on engine alone, and that is with very little development or experimental testing. It seems every year LSX world records are set when GM releases new engines, which makes this a truly exciting time to be a part of the GM performance community. The real horsepower wars didn't happen in the 1960's-the are going on today!