After what must have seemed like an eternity of waiting, Austin Everett, the vlogger behind the Speed Phenom channel on YouTube, just took delivery of his new C8 Corvette Z06 at the National Corvette Museum in Kentucky. Luckily for us, on his way back home to San Diego, California, Speed Phenom decided to make a stop in Texas at Dallas Performance to have his latest acquisition tested on the shop’s Dynojet in-ground chassis dynamometer. And the results are stunning.
The Run In
It turns out that the 700-mile drive between the Corvette Museum and Dallas Performance was quite important. This is because the Z06 electronically limits engine torque in low gears during the first 500 miles as part of the new vehicle's “break-in” procedure. Similarly, Chevrolet recommends refraining from full-throttle acceleration and downshifting to brake the mid-engine sports car during the break-in period. Having to refrain from mashing the loud pedal at every opportunity sounds like a major challenge to us, especially because Speed Phenom’s Z06 also has the optional Z07 performance package which includes:
- Carbon fiber aero package with larger front splitter, front-corner dive planes, a rear wing, and underbody strakes that enhance downforce
- Unique FE7 suspension with specific Magnetic Ride Control 4.0 calibrations
- Michelin Sport Cup 2 R ZP tires developed specifically for the Z06
- Available carbon fiber wheels that deliver a 41-pound (18.6 kg) reduction in unsprung mass
- Brembo carbon ceramic brake system featuring larger, 15.7-inch-diameter (398 mm) front rotors and 15.4-inch-diameter (391 mm) rear rotors
As you can see, Austin's Z06 (or is it Z07?) was pretty loaded with options and as such, cost about $185,000 "out the door" with taxes and fees. That's still a relative bargain for an American supercar that can run with the best of what Europe has to offer. However, like Toyota's GR Corolla and other high-demand vehicles, some unscrupulous dealerships and car flippers are adding an extra $50,000 - $100,000 markup above MSRP for the high-perf 'Vette.
The New LT6 Powerplant
While the base C8 Corvette Stingray is a very capable machine that is also eminently functional as a daily driver, there was a lot more performance potential bottled up in the mid-engine Corvette platform. The recently released C8 Z06 aims to unleash that performance with a focus on dominating racetracks. To accomplish that, Chevrolet made a bold maneuver to ditch the supercharged 6.2-liter V-8 used by the C7 Z06. Instead, engineers started fresh on a naturally aspirated 5.5-liter V-8 with a flat-plane crankshaft and 32 valves, derived from the C8.R endurance racing car.
Dubbed the LT6, this new powerplant cranks out 670 horsepower at a screaming 8400 rpm. Torque maxes out at 460 pound-feet at 6300 rpm, which is nearly the redline in a regular Stingray! The end result is a rocket that can accelerate from zero to 60 mph in only 2.6 seconds. This marvel of engineering is assembled by master engine builders at the Performance Build Center inside the Bowling Green Assembly Plant in Kentucky, where GM has made the Corvette since 1981.
The Moment Of Truth
In an auspicious beginning, the red 'Vette barely fit on Dallas Performance’s chassis dyno because the Z06 is a whopping 3.6 inches wider than the regular Corvette C8 Stingray. Its tires were at the very edge of the dyno rollers. According to the Dallas Performance staff, this is similar to dyno testing the Lamborghini Aventador, which is also uber-wide. Great care was taken strapping down the C8 to avoid scratching its carbon fiber Z07 wheels, but eventually, it was time for the moment of truth.
After three runs, the results were impressive. The first two dyno pulls calculated around 597 to 600 horsepower at the wheels. But after letting the engine cool down for an extended period, the Corvette Z06 laid down 610 horsepower at 8,400 RPM in fifth gear, achieving a wheel speed of 190 miles per hour in the process! That represents about a nine percent power loss from the engine’s crankshaft to the wheels.
Traditionally, losses from the transmission, transaxle, differential, etc. are estimated to rob about 15 percent of the horsepower as measured at the crankshaft. So Chevy either underrated the Z06 or the Tremec-sourced eight-speed dual-clutch gearbox is incredibly efficient. We suspect the former.
As a point of comparison, Dallas Performance showed that a 2021 Mustang GT500, which is rated at 760 horsepower at the crankshaft, made only 647 horsepower on their chassis dyno. So either the GT500’s drivetrain is much less efficient than the C8 Corvette's or Ford may have exaggerated the specs of their supercharged V-8!
Lastly, Sean Wilson from Dallas Performance stated that Chevrolet builds the Corvette engines with 100,000-mile longevity and warranty considerations in mind. But for customers that are more interested in extracting every last ounce of power, it’s not difficult to add an extra 100 horsepower with simple bolt-on parts. Perhaps Speed Phenom will be gracious enough to make the mods and return to the dyno to let us know? It's a tough job, but someone has to do it.