The new lap is still 0.3 seconds slower than the best time of the Dodge Viper ACR, but it's a significant step forward for the ZR-1. And on a 12.93mi (20.8km) circuit with over 170 turns, 0.3 seconds is the smallest of margins. Nevertheless, it's an impressive feat for the aging Chrysler machine. The ZR-1 on the other hand is still wearing its newness like a badge of honor.
The previous quick lap, reported by Corvette's chief engineer Tadge Juechter on the GM Next blog and hot-shoed by GM development driver Jim Mero, significantly raised the bar for affordable performance. By taking more than a full second off the Pagani Zonda F's time, the 'Vette is also quicker around the Green Hell than the Porsche Carrera GT supercar as well.
In both cases, the car was completely stock except for the addition of communications and safety equipment. Shod in production-spec Michelin Pilot Sport 2s, the car was also set to the same ride height and alignment figures as stock, making it exactly like the production cars that will begin production in the next few months at the plant in Kentucky.
Juechter claimed after the first record lap that there was more performance left in the ZR-1, and Magnussen's lap seems to have proved it. Even more speed could be extracted, but that would likely also require setup changes. As it stands, the ZR-1 was tuned in development to provide a very fast but still comfortable compromise position. If the car had been built exclusively for the track, like many supercars, the ride quality would have suffered too much for daily liveability, something that is a real consideration in a supercar as affordable as the ZR-1.
Video of the previous lap time of 7:26.4 can be found below.