How the C8 Corvette Z06’s LT6 Became the World’s Most Powerful Naturally Aspirated Production V-8


How the C8 Corvette Z06’s LT6 Became the World’s Most Powerful Naturally Aspirated Production V-8

Not only is the 2023 Chevrolet Corvette Z06’s LT6 engine the largest flat-plane crankshaft V-8 in the world, it’s also the world’s most powerful naturally aspirated production V-8, leapfrogging the 622-hp 6.2-liter M159 engine that powered the Mercedes-Benz SLS AMG Black Series from 2013-2014 and producing 670 hp at 8,400 rpm. How did Chevy more than manage to find “a replacement for [745 cubic centimeters’ worth of] displacement” relative to that mighty Benz? With better breathing and by spinning the engine a lot faster—horsepower is, after all, just torque times rpm divided by 5,252. Also note that at 460 lb-ft this is not the world’s torquiest V-8 (the Benz above made 468). Here are five ways Chevy accomplished this.

Two huge, 87mm throttle bodies feed a separate intake plenum for each cylinder bank of the Z06 engine. Altogether it holds 11 liters of air in total—twice the cylinder displacement. Fun fact: the C7 Z06 was fed by a single 87mm throttle body. Inside these plenums, each cylinder inhales through its own unique intake trumpet, angled in slightly different directions to optimize cylinder filling. The team would love to see the aftermarket develop a clear plenum that allows folks to see these trumpets, but it’s a structural part and it’s yet to be determined whether the plastic part can be reliably painted in Edge Red to match the cam covers, as shown on the display engine.

In a flat-plane-crankshaft V-8, the firing order always swaps from one bank to the other, lacking the syncopation cross-plane engines get from successive firing on a single bank (that’s what makes them burble). The real intake-manifold magic that leverages this potential volumetric efficiency windfall is a series of three valves connecting the two intake plenums that open in different combinations to vary the degree to which pressure waves communicate within or between the LT6 engine’s plenums.

For the full story, check out this article from Motor Trend.

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