The power in 2017 was off the charts
Almost a decade after setting a record in the C6 ZR1, he would return to the Nürburgring in an attempt to do the same thing in the C7 ZR1. Now, we've recently talked about this car in several stories. We took one for a virtual spin around the Green Hell in Assetto Corsa, but couldn't go faster than 7:37 by using a keyboard. It took quite a bit of effort to go that fast, and you can't help but think of how much better Jim's lap was in this machine. And we also looked at the auction history over on BaT to see how the market value for this rare sports car has evolved since it first rolled out of the factory.
Now, before we dive into the story, here's a brief recap of what the C7 ZR1 is capable of. Under the hood of this thing, you'll find a 6.2-liter V8 with a 2.6-liter Eaton supercharger that is rated for 755 horsepower (765 PS) at 6,300 rpm. Peak torque figures are just as impressive with 715 lb-ft (969 Nm) available at 4,400 rpm. Pratt & Miller have provided their input on the aero package for this vehicle, and the whole thing weighs 3,560 lbs (1,614 kg) in coupe form. We've read plenty of stories about GM's attempt at setting a record at the Nordschleife in the C7 ZR1, but we thought it would be best to learn the true version from the mouth of the man who did the driving.
Some people will tell you that he completed the 12.94 miles (20.83 km) lap in seven minutes and four seconds. While others have pointed out that he might have been even faster than that. "Our overall segment times for the 2019 ZR1 were significantly faster than 6:57. However, many of those segments were taken in April 2017. Those two weeks were very cold which normally aspirated engines love. The power in 2017 was off the charts. The great hope was when we went back in April 2018 that we would benefit from the same ambient temperatures."
Needless to say, we were furious
But things don't always go according to plan. And there are always some changes being made to the way things are handled at the Nürburgring. "For 2018 the Nürburgring decided to change the format in which fast laps are conducted. Also, the Industrypool session in March 2018 was canceled due to snow. So we would be the first to run the new format. The new format would be a 1.5-hour session after Industry Pool had concluded. However, the 1.5 hours would be split with any manufacturers who wanted to participate. I had no problem with that thinking I would at least get two shots to run for time."
You have to be aware of the fact that setting a record isn't all about just going for a fast lap. Tires have to be brought up to temperature, and the driver needs to warm up as well. One has to get in the zone before he can go all out in a car that powerful, and one such a challenging layout. But Jim and GM were about to take another unexpected hit that week. "One hour before we started the session for timed laps, the Nürburgring had a meeting and changed everything. They decided that we would not enter the track where we normally do."
"Instead, we would enter near the end of the long straight right before you go under the second bridge, go through three turns and begin the lap for time. They also decided to put a bus stop chicane right before the start line. Also, there would be no warm-up lap. So, we would have approximately 3/4 of a mile (1.2 km) and three turns before we started for time. Now, up until that point for a fast lap, I typically only had one lap to get the time. But I always got a warm-up lap before the timed lap. I had the warm-up lap perfected to have the tires at peak grip in the first turn of the timed lap. We just assumed the Nürburgring’s new protocol would include a warm-up lap, and it was never implied that we would not until one hour before the session for time."
It might've been one of the best laps I had ever driven
"And suddenly, we knew that going sub 7 minutes was impossible. We had tire warmers, but that was pointless. To properly warm up tires takes four to six hours. You must bring them up to temperature slowly, then about 45 minutes before they go on the car you crank them up to 200°F (93.333°Celsius). We did think it was odd when Porsche rolled up with a semi-truck and rolled out four or five tire ovens filled with tires. I had no choice but to just go for it."
Most people have probably seen race car drivers swerve left and right before the start of the race to bring the tires up to temperature. But Jim provided a more in-depth explanation of that process and what it takes to get things working properly. And with our limited virtual C7 ZR1 driving experience we can vouch for the fact that this car can be a handful even when the tires are working at their best.
"The proper way to warm tires on the track is to utilize tractive and normal forces to slowly warm up not only the tread but the entire carcass, sidewalls, the wheels, everything. Instead, I was using slip angles that were larger than anything we had ever seen. Slip angles are not the way to warm up tires. I’m talking about a car that was perfect an hour before, and it was perfect the next morning, but on cold tires the grip was terrible. Even when they got some temperature into them the balance was so far off."
One can only imagine how fast the ZR1 could have gone if not for all the challenges encountered by the team. Perhaps that would have made for a difficult moment for Porsche, Lamborghini, or Mercedes. Alas, we may never see another official GM test of it on the Nürburgring, but we can only hope that they'll bring out the C8 Z06 for a fast lap sometime soon. If you've enjoyed part three of our Jim Mero story, you'll be happy to see part four coming out soon.