• Mar 20th 2011 at 12:25PM
  • 12
2011 ALMS Corvette racing engine – Click above to watch video after the jump

The Chevrolet Corvettes that do battle in the American LeMans Series are, at first glance, acres removed from their street-dwelling cousins. Beneath the skin, though, the two cars are more similar than you might think, given their differing purposes.

For starters, Chevrolet uses similar engine architecture for both cars. The ALMS Vettes use the exact same block that goes into the Corvette Z06. That's where the similarities end. The racing engine is limited to two 28-mm air intakes in a bid to level the GT Class playing field. The ALMS engines are also limited to 5.5 liters of displacement, versus the production car's 7.0 liters.

Though the means may be different, the end is the same: maximized power and efficiency. Chevrolet develops and builds its racing engines in-house, to try and insure that some of the technology that goes into its endurance racers makes it into its street cars. To hear Chevrolet tell it, check out the video after the jump.

[Source: YouTube]



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    • 1 Second Ago
  • 12 Comments
      • 4 Years Ago
      ALMS rules are set up by a bunch of euro-snobs that are afraid to let Corvettes compete on a level playing field with their girly Porsches and BMW's.
      • 4 Years Ago
      MORE!!! Love these videos!!!
      • 4 Years Ago
      They must've massively destroked that engine, which could be a good thing since it lowers piston speed and allows higher RPMs.
        • 4 Years Ago
        The LS7 is 104.8mm x 101.6mm. With NASCAR/F1 friction tuning it might hit 7700rpm. If it were tuned for racing, and fueled with high octane gasoline, the engine could probably produce around 800hp-850hp depending upon the efficiency of the top end.

        Assuming the LS7 is only destroked, they have to reduce stroke by about 22mm to around 104.8mm x 79.6mm. The maxed out rev limit would be around 9800rpm. Peak horsepower would be roughly the same as the 7.0L version.

        The cars only produce around 500hp with the air restrictors equipped. Without air-restrictors 500hp would be achieved around 6,000rpm by a 5.5L engine, but I have no idea how much impact the air restrictors have on the rev ceilings. These are ballpark figures. I don't have the homologation forms, and I'm not a race engineer so don't take this as gospel.
      • 4 Years Ago
      I wish he went into more detail on what methods they apply to raise efficiency. Feels like the movie ended just as it was getting into the meat of the topic, damn. And the main presenter could use a happy pill.
      • 4 Years Ago
      That just shows how much they've lowered the engine mounting if they can put all that huge intake stuff on top and still fit it under the hood.
        • 4 Years Ago
        They also don't have to worry about potholes or speedbumps, like a road car. :D
        • 4 Years Ago
        What needs to be under a dry sump race engine?
      • 4 Years Ago
      no explanation of how they get a 7.0 down to a 5.5? do they just slice off the top bit from each side of the block?
        • 4 Years Ago
        Different stroke.
        • 4 Years Ago
        "Different stroke"s...

        ...for different folks.
        • 4 Years Ago
        The LS5.5R is 4.090"x3.185". A smaller bore and shorter stroke than a production LS7. If you look closely in the video you can see that the LS7 blocks they are starting with do not have liners installed in them yet.
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