GM Engineers Went Old School to Make the C8 Z06 LT6 an Amazing Powerplant

Though created using advanced tech, the C8 Z06 LT6 uses the same basic design that’s worked flawlessly for over a century.

By now, we know pretty much everything there is to know about the C8 Corvette Z06 and its piece de resistance – the high-revving, sweet-sounding, naturally-aspirated, flat-plane crank V8 under its bonnet. The most powerful N/A V8 in production car history, it’s safe to say that the LT6 was designed using the latest and greatest technology, but on the same token, it’s also decidedly old school in its approach, with zero forced induction or hybrid power assist. As it turns out, that was precisely the goal, as Popular Science recently discovered while speaking with the engineers that designed it.

“We will never implement technology for technology’s sake,” said Jordan Lee, chief engineer for Chevrolet’s Small Block team. “There has to be a real tangible benefit to the customer for it to be considered.” Instead of just throwing a bunch of futuristic components at an engine with the hopes that they’ll wow customers, Lee notes that new ideas are fine, but they must also “earn” their way into a project based on merit.

Thus, while the Small Block team uses the latest and greatest in terms of analysis tools, digital design, manufacturing processes, and advanced materials, at its core, the LT6 essentially operates the same way as internal combustion engines dating all the way back to the late 1800s. Eight years ago, Corvette chief engineer Tadge Juechter tasked his team with finding a way to develop an engine that was more powerful than the supercharged LT4 present in the C7 Z06, albeit while also going backwards in a sense and ditching its supercharger for N/A power. The idea here was to ensure that the new Z06 could run all day at the track without overheating, and it’s capable of doing precisely that – in 100 degree weather, with the air conditioner blowing.

In addition to that, the LT6 utilizes a mechanical valvetrain rather than a more modern hydraulic setup – which dates back to the 1900s, though it was largely ditched by the 1970s. The reasoning behind this is simple – a high-revving, short-stroke, twin overhead-cam powerplant like the LT6 could experience valve float if those units aren’t capable of keeping up, which can lead to catastrophic failure.

“With a mechanical valvetrain you really simplify everything,” said Small Block team assistant chief engineer, Dustin Gardner. It’s “a modern interpretation of an old school way to build a valvetrain.” Additionally, the team molded the engine’s intake manifold a total of 50 times to perfect it, though that resulted in 33 percent more air flow than the original design – as much as a larger 6.0-liter V8. “The LT6 is capable of about 110 percent peak volumetric efficiency. It’s effectively supercharging itself due to the harmonics and the resonance tuning in the induction system, helped by the flat-plane crank,” Lee said.

That doesn’t mean that the LT6 is some dinosaur by any measure, of course, as the Small Block team was given total creative freedom to create a clean-sheet powerplant in this case. “We were super excited that we weren’t restricted to anything typical of a high volume production truck or passenger car engine,” Lee said. “We were allowed to pick the best technology that we knew of to make the LT6. Boosted engines can come on really strong and there are some good ones out there including some from GM. But we like to think everything we do with the Corvette Z06 should tantalize your senses, including the engine. To me, nothing sounds better than a naturally aspirated V8 – it’s part of the emotional connection of the LT6-powered Z06 on top of the performance.”

Photos: Chevrolet

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