It looks like the 2020 Chevy Corvette isn’t more powerful than GM says it is after all.
We’re not sure if this is disappointing or affirming. MotorTrend recently ran a correction on a previous article that explained how they dyno tested the new C8 Stingray and found it to make close to 650 hp instead of the 495 hp that Chevy says it did.
At the time, we were all shocked. A number that big is usually reserved for the Z06 trim, not the base Corvette. And why would GM lowball their Corvette’s power figures so drastically? They have no reason to, unlike Toyota and their new Supra (where we assume there’s a gentleman’s agreement to not upstage the BMW Z4, which actually has less power than it’s Japanese-built twin).
GM responded to MotorTrend’s test by saying they performed a far more thorough evaluation of the Corvette’s performance using standards set out by the Society of Automotive Engineers (SAE). Which sounded reasonable, but that still put things in a difficult “he said, she said” position.
Corvette fans and other publications also cast doubt on MotorTrend’s numbers. So much so that MotorTrend went back and investigated their original data and discovered that there were some errors made during their tests.
The first error was in determining the C8's road-load at 50 mph. MotorTrend didn't have an accurate value for this, so they just used the C7's number as a rough approximation. It turns out, the two numbers actually differ by a good 20%, so it was a bad guesstimate.
The second error was in the dynamometer itself. It was set to assume the car being tested was all-wheel-drive, which the Corvette is not.
"These two factors conspired to make the dyno believe the Corvette's powertrain was overcoming way more inertia than it really was, which led to the inflated results," MotorTrend admitted.
They weren’t able to correct the numbers from their original pull, so instead, they did a few road tests using Vbox data and got power figures a lot closer to the 495 horses and 470 lb-ft that GM advertises. Still plenty of power, but we’ll have to wait for the Z06 trim before the 2020 Corvette starts making 650 hp.