Why The Corvette Z06 Flunked Motor Trend's Big Performance Car Test

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The new 650 horsepower Chevrolet Corvette Z06 is a fucking amazing car, but it’s had its share of mechanical headaches for owners. It also flunked out of Motor Trend’s heavily hyped Best Driver’s Car test. Here’s how it went down, according to General Motors and everyone else.

According to the top Corvette engineer himself, the Z06 that DNF’d with Motor Trend wasn’t in great shape going into the test; not after it got stuffed into a wall courtesy of Car And Driver.

That comes not from Car and Driver themselves, who ran the car at their Lightning Lap test before MT got hold of the Vette, complete with track-focused Z07 package. Instead the world heard this from the head of Corvette engineering himself, Tadge Juechter. Juechter had to explain why their Z06 heat soaked itself out of the running for Motor Trend’s Best Driver’s Car test at Laguna Seca.


You can read MT’s test in that link above, and you can watch their tame racing driver Randy Pobst explain exactly how the car stuttered on track in the video below. He says it felt like a ‘62 Ford on the straightaway.

Tadge explained those faults by saying that he and his team forgot to change the brake pads on the car, then failed to hook up the intercooler right. He’s not exactly an unbiased source, but here’s his report, originally posted on Corvette Forum and brought to our attention on The Truth About Cars.

During testing at C and D the car went off track into a tire wall. Stuff happens. It wasn’t the first time this has happened and I’m certain it won’t be the last. Fortunately, the damage to the car was cosmetic (rear fascia, supports and the energy absorption assembly). It didn’t have any fundamental structural or chassis damage. The alignment was fine. Basically, zip ties and some duct tape was all it took to make it track-worthy. The car then went out and ran the second fastest Lightening Lap they have ever recorded.

Any time there is an incident like that, we have to tear the car down, replace broken parts and make it like-new again. In the few days we had to prep the car for Motor Trend, we did a tremendous amount of work to make sure the car was safe, capable and pretty.


This sounds like it was a pretty serious wreck the way Tadge puts it. I got a hold of Car and Driver’s editor in chief, Eddie Alterman, and asked him about the crash. I also asked him why the incident hadn’t shown up in their online posts, but he said it’s coming in this month’s print magazine.

...I wouldn’t describe the Z06 incident at VIR as a crash. We went off at Turn 3 after being distracted by a flag, and tapped the tire wall with the rear of the car. We drove it back to the pits and zip-tied the lower bumper seam together.

As you know, Turn 3 is nicknamed NASCAR because it’s where the road-course guys go off. It’s a tricky corner. But the off didn’t put the car out of commission for more than an hour or so. We didn’t mention it in the limited space of piece and let Ezra handle it in his column.


That doesn’t sound particularly rough on the car. It would take a lot more to put the Z06 out of the running with Motor Trend.

“In our haste, two things were missed,” Tadge says about the work done on the Corvette post-Car and Driver. Those two things were that GM forgot to change the car’s brake pads and they didn’t correctly hook up the car’s intercooler, according to Tadge.


You can see the car’s integrated supercharger/intercooler mounted on the Z06’s V8 in these two pictures.


Above is the system mounted in the car and below you can see it in a cutaway.


Here’s Tadge’s detailed explanation.

The second unfortunate occurrence related to the intercooler circuit. One of our pre-loan checks is to bleed the intercooler circuit to make sure there is no air in it. Some customer complaints about over heating Z06s have been traced to improperly bled intercoolers. The technician doing the work plugged in the electrical connector for the intercooler pump and it seemed to seat and “click” into position, but the secondary latching mechanism did not fully lock into position leading to intermittent operation. Without the pump running there is no coolant flow, no intake charge cooling and the engine pulls spark to protect itself.

That is what Motor Trend experienced at random times during their testing. Unfortunately, the connector was seated enough that the pump and engine worked fine in all the pre-test driving done before trucking the car across the country to Motor Trend in California. Remember this is the same car that performed flawlessly a few weeks prior in sweltering heat during Car and Driver’s Lightning Lap. The possibility of bad fuel was discussed because it was clear there was an abundant amount of spark retard, but we didn’t discover the true root cause until the car had returned to the Milford Proving Grounds after the test. We have modified our procedure to run the pump remotely during the bleed process so this issue can be avoided in the future.


When you’re reading these year-end tests of production cars—supposedly similar to the same ones ordinary people can buy—it’s good to remember that this kind of service is totally normal. I’m sure all Corvette owners get their cars regularly checked at GM’s head test facility.

To be fair, GM themselves are blaming this one on poor servicing, with Tadge even saying the same Z06 “performed flawlessly a few weeks prior in sweltering heat during Car and Driver’s Lightning Lap.” But it’s still a big black eye for a car that’s supposed to be the beacon of everything GM does well.


Tadge even got interviewed by Stanford talking about the reinvented atmosphere at GM and Corvette. He also talked about how the ‘Vette is supposed to act as the shining light that leads the way for the whole company. “Corvette is the tip of the technology spear,” he noted.


So when the top Corvette gets borked, every American car fan cringes.

Also, this is far from the only problem that’s troubled the Z06. One car had a complete engine failure in the hands of a journalist, and owners have experienced more.


I’m blaming this all on Corvette putting a supercharger on the Z06. This is the kind of stuff when you ditch a purebred naturally aspirated formula, GM. Forced induction is the devil’s work.


Photo Credits: GM

Contact the author at raphael@jalopnik.com.