How Chevy Designed the World’s Largest Flat-Plane-Crankshaft V-8 for the 2023 Corvette Z06


How Chevy Designed the World’s Largest Flat-Plane-Crankshaft V-8 for the 2023 Corvette Z06

Back in February when we reported future Corvette learnings from a GM insider we dubbed “Deep Burble,” our technical staff pushed back hard on the notion of a new 5.5-liter flat-plane-crankshaft V-8 engine. Flat-plane-crankshaft V-8s vibrate like two four-cylinder engines strapped together. That’s why the performance-engine world largely held the line on displacement of such V-8s to around 4.5 liters, until Ford pushed the envelope with the Ford Mustang Shelby GT350’s 5.2-liter Voodoo engine. Ford’s bold move came at the expense of some durability issues, however, so when we were invited to ride along with development engineers in the 2023 Chevrolet Corvette Z06, our very first questions were all about how the sports car’s 5.5-liter flatty solves the vibration question—especially with its 8,600-rpm redline.

We have a great explainer article outlining the differences and benefits of each crankshaft design here, but in a nutshell, a flat-plane V-8 crankshaft looks just like an inline-four crank with its throws 180 degrees apart and with room for two rods on each throw, whereas the cross-plane crank divides up the throws at 90 degree angles. The earliest V-8s all used flat-plane cranks, until in 1923 Cadillac introduced a cross-plane crankshaft with counterweights that quelled the nasty secondary vibrations (those that happen twice per revolution) inherent in a flat-plane crank for a smoother, more luxurious experience. Sports cars care less about comfort and more about squeezing the most power out of each drop of fuel, and flat-plane cranks help do that. But the bigger the pistons and the faster they move, the greater the secondary vibration, which can ultimately prove damaging to the engine and things that bolt to it. Hence why a V-8 as large as the Z06’s 5.5-liter is so surprising a choice for a modern engineering squad.

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

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