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C1 - 1953 to 1962
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1968
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* Added 1-16-08
C7 - the Future Corvette

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C7 Reveal
Engine - The New LT1 Engine
Exterior - A New Look for a New Generation
Interior - Finally World Class
Chassis -An Aluminum Masterpiece
Driveline - The Electric Vette!

Engine - The New LT1 Engine

The Chevrolet (GM) small block V8, More of these engines have been built than any other automotive engine on the planet. Not only do they power automobiles like the C7 Corvette, but they also move boats over water, run generators, industrial equipment,ect. Basicly if a engine can run it, somewhere a small block V8 does it.

Todays small block is the fifth generation of an engine design that employs the cylinders arranged in a 90-degree V, pushrod operated overhead valves, and 4.4 inch bore centers, That is basicly where the commonality ends between the Ed Cole designed small block of 1955 and the next generation. The new engine borrows only the look and name of small blocks past.

The new engine builds on the properties of the Generation 4 small block. It has a cast aluminum cylinder block with cross bolted nodular iron main bearing caps. On the fourth generation small block, the main bearing caps were constructed from powdered metal castings. The block extends beyond the crankshaft centerline, providing the support necessary to contain the 11.5:1 compression ratio. While the block is made of 319 cast aluminum, the cylinder liners are made of cast iron for duarability and are cast into place. For increased durability and sealing, the liners are cast over. At the rear of the block, the high pressure mechanical fuel pump for Direct Injection is cast into place.

The LT1 will be available with either a wet or dry sump oiling system, both using a front mounted gerotor oil pump. . Chevrolet's first use of a dry sump on a production car was on the 2006 Corvette Z06's 427ci LS7 V8. The dry sump system has a seperate oil tank that comes factory filled with 10.5 quarts of GM Dexos 5W30 semi-synthetic engine oil. Pervious Corvettes have specified Mobil 1 full synthetic oil. The lubrication system also has presurized oil cooling jets that spray oil on the bottoms of the pistons and give the cylinder walls additional oiling to reduce wear. The oil spray only occurs at startup and during high engine speeds when the thermal loads are higher. An added benefit of the jets spray on the cylinder wallsand wrist pin area is noise reduction. The crankshaft is a stout piece, made from 1538MV forged steel, with induction hardened journals for increased durability. Even the main bearings are upgraded with increased bearing surface, a reult of a 1.5mm narrower upper grove in the bearing, now limited to 4mm. To further stiffen the block, a cast aluminum oil pan that serves as a structural menber is used.

GM began building direct injected engines in 2008 for U.S. consumers, but this is GM's first attempt at building a DI overhead valve gasoline V8. The injectors which spray fuel at much higher pressures than electronic fuel injection systems rely on an engine driven pump that uses an extra lobe on the rear of the camshaft. The pump operates at 2,175psi and has a flow rate of 1.49ccs of fuel per engine revolution. This fuel is distributed along the fuel rail where the fuel is injected directly into the combustion chambers, optimizing fuel delivery. The flow rate of these injectors maximizes at 22ccs per second.

Like the block, the cylinder heads are of a new design, displacing only 59.02ccs of volume. The compression ratio is 11.5:1, the highest compression ratio of any GM small block, yet still a point lower than the closed chamber L88 427 V8. That engine had a race car like 12.5:1 compression ratio. With the combustion chamber's small volume, reliefs in the pistons were developed to provide more complete combustion using less fuel and lower emissions. The relief pockets work in conjunction with the variable valve timing as the the cam phasing will allow the valves to be in an open position when normally they should be closed. The pocket keep the valves from coming into contact with the pistons. In the effort for more complete combustion, the spark plug has been relocated, now residing closer to the center of the combustion chamber. The valve sizes remain the same as the LS3 at 2.165" for the intake and 1.59" for the exhaust, however the intake and exhaust valves swap positions. The valves are now splayed at 2.5 degrees to optimize the flow rate of the heads. The engine is still comact, a benefit of using a cam in block, overhead valve arrangement.

By emloying variable valve timing, the cam can be phased by a total of 62 crankshaft degrees, giving the C7 maximum performance or economy, depending on the will of the driver. In the older small block V8s, a 1.5 rocker arm ratio was used for Years. Afermarket suppliers affered 1.6 or 1.65 rocker arms, which meant a lower lift cam tould provide greater overall lift without a camshaft change. The LT1 will go well beyond what Ed Cole could have envisioned by using a 1.8 rocker arm ratio. This has been used in another small block; the ZR1's 638hp supercharged LS9 V8. The gross camshaft lift is the same as the LS3, with.551" of intake lift and .529 for the exhaust. The duration of a lift event is 200-degrees on the intakes and 207-degrees for the exhaust with 116.5-degrees of lobe seperation.

The intake plenum continues to be contructed of composite materials, and is termed as a "runners in a box design. The plenum is designed to supply a rapid charge of air under high engine speeds. The air is injested by 87mm throttle body. The plenum is designed to lower the engine noise with acoustic foam layered attop the plenum to reduceinduction noise and the plenum itself damping mechanical noises from the inner workings of the engine. On the exhaust side of the combustion process, thin wall cast iron manifolds replace the tubular steel manifolds of the LS3. By constructin the manifolds out of cast iron, engine exhaust noise is dampened.

The result is and engine that is expected to propel the C7 Corvette from 0 to 60 in under four seconds. The LS3 in a Corvette is rated at 26mpg highway, and the LT1 is anticipated to better that. All in all the LT1 is an efficient, lightweight, powerful engine, packed in and exceptionally small package. A world beater indeed!

C1 - 1953 to 1962
C2 - 1963 to 1967
C3 - 1968 to 1982
C4 - 1984 to 1996
C5 - 1997 to 2004
C6 - 2005 to 2013
C7 - The Future Corvette - 2014 to ?

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