Motor Trend has admitted the C8 Corvette's dyno test results were wrong.
Officially, Chevrolet claims the 2020 Corvette Stingray's 6.2-liter LT2 V8 produces 495 horsepower and 470 lb-ft of torque, but MotorTrend recently discovered the mid-engine sports car could be significantly more powerful than advertised. After performing a dyno test, MotorTrend concluded the new Corvette produces a whopping 656 hp and 602 lb-ft at the crank – that's 161 more hp than Chevrolet claims.
Factoring drivetrain loss, this equates to 558 hp and 512 lb-ft of torque at the wheels. MotorTrend discovered an issue with gear ratios so the car was tested again with results of 478 hp and 544 lb-ft at the wheels (562 hp and 640 lb-ft at the crank), which is still more powerful than Chevrolet claims.
If this seems too good to be true, that's because it is. Many people were skeptical about the results, and after investigating the dyno test, MotorTrend has admitted it made some mistakes. According to the publication, the dyno operator selected two dyno settings that were incorrect.
One was the road-load horsepower at 50 mph, which incorporates friction and aero drag. Due to the short amount of time MotorTrend had with the C8 Corvette, the number was estimated to be 12.6 based on C7 Corvette data, but Chevrolet has confirmed it should have been 15.4. As for the other error, the dynamometer was set to all-wheel drive. As a result, the Corvette's powertrain was overcoming more inertia than it really was, leading to inflated results.
To correct the mistake, MotorTrend examined data from their best drag strip runs. The results showed the Corvette produces around 500 horsepower. However, MotorTrend managed to perform a "road dyno" test on a second Corvette and found it delivered a "shade under the rated output" of 465 hp and 412 lb-ft of torque in second- and third-gear.
These results aren't necessarily conclusive, however, as the road-dyno testing may "involve too much uncertainty or speculation," but the publication is "convinced our red test car was certainly making every bit of its rated output of 495 hp at 6,450 rpm and 470 lb-ft at 5,150 if not slightly more." With this setup, the C8 Corvette will hit 0-62 mph in 2.9 seconds with the Z51 package installed.