2020 CORVETTE C8’S HORSEPOWER, TORQUE FIGURES MAY BE SERIOUSLY UNDERRATED
Officially, the mid-engine 2020 Chevrolet Corvette’s 6.2-liter naturally aspirated V8 produces 495 hp and 470 lb-ft of torque at 6,450 rpm and 5,150 rpm, respectively. But a series of dyno pulls Motor Trend performed on a test car suggest that it could produce more — much more.
The publication managed to strap one of the Corvettes to a dynamometer and was surprised to record 558 hp and 515 lb-ft of torque at the wheels; assuming a 15 percent drivetrain loss, that works out to an estimated output of 656 hp and 606 lb-ft. (And even assuming an impossible zero percent drivetrain loss, the V8 was still putting out way more than the official numbers.)
Further pulls revealed similar numbers, so this wasn’t a one-off anomaly — something is up here. The possibilities as we see it:
– Chevrolet is dramatically underrating its engines
– This particular press car has been tuned to put out much more than your average stock 2020 Corvette will produce
– Differences between testing methodologies used by Motor Trend and Chevrolet, and/or conditions on the day of testing, account for the difference
– The dyno Motor Trend used is way out of whack
Underrating engines is not an unheard-of practice, but that shouldn’t be the case here: The new Corvette engine’s output has been independently certified by the Society of Automotive Engineers (SAE). So the horsepower and torque for the model should be more or less known quantities.
Differences in testing methodologies could account for the gap between stated and apparent output. Of the SAE’s approach, Motor Trend writes:
“Their testing does not involve a simple pull from idle to redline, either. Rather, rpm are slowly ramped up and allowed to stabilize before accelerating further. This process results in significantly more heat generation than any single pull from our six dyno runs. For that reason, the engineers say, it’s not uncommon for single chassis dyno pulls to register higher output (and it is extremely unlikely any car will ever generate less than rated output).”
So that could explain some of the discrepancies, but we’re not talking about a few percentage points difference here. Could the problem be in the dyno? That’s certainly possible — dynamometers are great for showing relative increases in power (e.g., boosted output after an engine has been tuned or otherwise modified) but shouldn’t be automatically trusted to provide accurate baseline figures.
But Motor Trend says it’s taken that into account:
“The dyno we used complies with the SAE J1349 procedures, and we’ve used it multiple times in the past. To prove there wasn’t a problem with the dyno, we ran a 2020 Ram 2500 Limited powered by the 6.7-liter turbodiesel Cummins engine, which produces 850 lb-ft of torque but is not SAE-certified. The dyno read 760 lb-ft at the wheels, which means there’s about 890 lb-ft at the crank, much closer to the numbers Ram claims.”
Head to the Motor Trend article to see all the numbers, check out the dyno test reports and read more about the test methodology. There’s some speculation about what may be behind the higher output, including the possibility that the publication’s test car was punched up by Chevy. Until publications can test multiple cars on multiple dynos, we won’t have any real sense of what’s going on.
You can read our first drive of the 2020 Corvette here; we haven’t managed to strap one to a dyno just yet, but be on the lookout for more drives and impressions of the car in the coming days.
Souce: Graham Kozak, AutoWeek