When you read the amount of horsepower a car produces, you see how much power the car makes at the crank. Real-world horsepower is lower and is often measured at the wheels using a dynamometer (dyno). The lower horsepower number is attributed to drivetrain loss – power lost through friction and rotational inertia. Every car suffers some drivetrain loss, including the 2019 Chevy Corvette ZR1. Earlier this week Hennessey Performance released a video of a few employees driving the ZR1 and yesterday the aftermarket tuner released a video of the supercar on the dyno.
The ZR1 suffers about a 13-percent drivetrain loss. At the crank, the ZR1’s supercharged 6.2-liter LT5 V8 engine produces 755 horsepower and 715 pound-feet of torque. However, at the wheels, the ZR1 makes 654 hp and 645 lb-ft of torque. That means 101 horsepower disappears due to drivetrain loss. Now, that doesn’t mean the ZR1 is a slouch. The 654 hp at the wheels means the ZR1 can hit 60 miles per hour from a standstill in 2.85 seconds and hit 100 mph in 6.0 seconds. The supercar is capable of completing a quarter-mile race in 10.6 seconds at 134 mph.
The ZR1 with “just” 654 hp still packed enough punch for Hennessey employees to sing praise about the high-performance Corvette. Reactions from the earlier video ranged from “For a stock vehicle this is really impressive” to “I’d lose my license in about a week.” And it’s not like drivetrain loss only affects the ZR1. Automobiles with SAE International horsepower ratings show the horsepower at the crank. These vehicles lose horsepower through drivetrain loss just like the ZR1.
If you’re not happy with the drivetrain loss, Hennessey already has three performance packages available for the ZR1 ranging from the HPE800 to the HPE1200. The base package produces 850 hp and 715 lb-ft of torque. The HPE1200 pack produces an absurd 1,200 hp and 1,066 lb-ft of torque thanks to a host of modifications that include a 7.0-liter engine upgrade and a high-flow supercharger. That should make up for any disappointing drivetrain loss.
Source: Hennessey Performance