Now that the 2020 Corvette C8 is officially out in the world, all us auto journalists finally have a chance to poke and prod it to see what makes it tick. Motor Trend took the opportunity to put the new mid-engine Chevrolet Corvette on the dyno to see what sort of numbers it would post, and long story short, the results are unbelievable.
After acquiring a pre-production build for testing purposes, Motor Trend ran six dyno pulls with the 2020 Corvette. The numbers from the first run left the testers floored—558 horsepower and 515 pound-feet of torque at the wheels. Holy moly.
Those are huge numbers, far above Chevy’s claim of 495 horsepower and 470 pound-feet of torque with the optional performance exhaust system. What’s more, it has to be said that the manufacturer’s claimed numbers were certified by the Society of Automotive Engineers (SAE), which conducts much far rigorous testing then the runs performed by Motor Trend.ù
After doing a few more runs and talking to various experts, Motor Trend was stumped. The testers also strapped up a 2020 Ram 2500 to see if the dyno was wonky, posting 760 pound-feet of torque, a bit closer to Ram’s claimed 850 pound-feet of torque.
After all the runs, the 2020 Corvette’s lowest numbers were 478 horsepower and 536 pound-feet of torque.
Road & Track’s Jason Cammisa ain’t buying it. In a post to Instagram, Cammisa laid out some math and specs on why Motor Trend’s numbers don’t make any sense.
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The C8 Corvette Stingray does NOT make 650 hp! A certain media outlet published a story today that they dyno’ed one and got more than 500 hp at the wheels… calculating back to 650 hp at the crank. This isn’t possible. 650 hp from 6.2 liters of displacement can’t happen with at only 6500 rpm without forced induction. Horsepower is a function of torque x rpm… and there’s a maximum torque-per-displacement (otherwise known as BMEP, or Brake Mean Effective Pressure) that’s vastly exceeded by Motor Trend’s dyno runs. MT’s 630 lb-ft number suggests the LT2 makes 17.2 bar BMEP. The most efficient naturally aspirated engines are around 13. The LT2 is SAE rated at 12.9. Did it have turbos on it that no one saw? I suspect not… but they sure didn’t show up in acceleration testing… Here’s the real reason I know the dyno results are invalid. See the screen-shot on image 2. This is my acceleration simulator. My nerdiness knows no boundaries, but I’ve been using this calculator since the early 1990s. I inputted a DynoJet plot from a 7-speed manual Z51 C7 I found on the Internet… 417 hp and 415 lb-ft at the wheels. Then I plugged in the C8’s actual weight, gearing, tire size, and I estimated drag coefficient and frontal area. The numbers (in black, on the right) line up almost exactly with the testing results @roadandtrack got (in red) – within ~0.3s all the way to 150 mph. The most damning is top speed, which calculates to 182 mph. Chevrolet claims 184 mph for the Z51 C8. I’d expect a couple mph higher with the C8’s LT2 engine (495 hp instead of the C7’s 460 that I used here.) If the thing really made 650 hp, top speed would be vastly higher. Like, 200+ mph. MT’s dyno piece doesn’t pass science muster. I’m disappointed that they published it — something was clearly broken on that dyno. They should have brought it elsewhere and re-tested. Or at least realized that the numbers didn’t line up with the reality of their tests. #C8Dyno #CorvetteDyno #C8Power #C8 #C8Corvette #Corvette #Dyno #DynoJet #Dynamometer #Science
We agree that the Motor Trend numbers don’t really add up. While manufacturers do slightly underrate power and torque numbers from time to time, the discrepancy here is far above anything like that. While it’s possible the tester was simply tuned to produce more power, we think the much likelier suspect is the dyno itself.
We’ll stay on the lookout for further developments. In the meantime, subscribe to GM Authority for more mid-engine Corvette news, Corvette C8 news, Corvette news, Chevrolet news and around-the-clock GM news coverage.
Source: Motor Trend