Corvette Chief Engineer Explains Motor Trend "Best Driver's Car" DNF

Mark Stevenson
by Mark Stevenson
corvette chief engineer explains motor trend best driver s car dnf

When you bring your halo-of-halo sports cars to a competition to sort out the “Best Driver’s Car”, you definitely want to give it a new set of brake pads, make sure all the electrical connections are seated properly, and maybe — just maybe — not send a car that was offed in a previous comparison test.

But that’s just what Chevrolet did for this year’s edition of Motor Trend’s “Best Driver’s Car”, and it came back to bite the General — hard.

In a post on Corvette Forum (via MotorAuthority), Corvette chief engineer Tadge Juechter explained just why the 650 horsepower, LT1-powered Corvette Z06 was unable to finish the test. Since Tadge insists on giving context, here was his reply nearly in its entirety:

During testing at C and D [Lightning Lap] 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. In our haste, two things were missed.We always replace brake pads before delivering a car, but this was missed. I can’t remember this ever happening before, but it did. We have since changed our pre-test check procedure so this can never happen again. Although Motor Trend made it a point in the article, they did not notice any issue with braking performance during their spirited street drives. Our engineer on-site noticed the linings were worn, and they were immediately replaced and burnished. This was done the day before the Z06 was run on track by Randy Pobst and had absolutely no bearing on the results of the test.

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.

If you want to check out the comparison for yourself, here you go.

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  • Wstansfi Wstansfi on Oct 16, 2015

    Here's the thing - there was a GM engineer on site, and they couldn't sort out the problem the whole week. If they can't sort out the engine tech issues for MT, over the course of a week, for an event like this, it makes me wonder what the ownership experience would be like for the average person buying the car. Truly, you get what you pay for... The so-called bargain supercar not much of a bargain if engine going to "limp mode" and other issues yet to be determined...

  • VenomV12 VenomV12 on Oct 16, 2015

    Here's what it boils down to, GM really doesn't care. Within my neighborhood and in a five mile radius there are at least 5 new Z06s, at least two of them with Z07 packages and whenever the dealerships in town get new Z06s they go fast. GM is selling them, selling them for full freight and the Z06 tested in the race could have blown up in a ball of fire, killed 10 people and it probably would not make a dent in their sales. They are probably trying to figure out how to add a Z08 package or something else so they can charge even more money, they just don't care. I am blown away by how well they are doing, around here I see more new Z06s on the road than Stingrays, ditto for when I am down in Texas and Oklahoma also. I remember back in the 90s Car and Driver or one of the other mags did a side by side review of a Lamborghini and a Ferrari and by the end of the test both were barely running and had a long list of stuff broken on them and it didn't matter, people still buy them and buy them all. It's not a Malibu or a Camry, no one cares that buy them cares. Like I said in the previous post, the guy down the road from me, his C6 Z06 burned his house and his cars down and he still just went out and bought a C7 Z06 with the Z07 package, if a car burning your house down doesn't deter you from getting another one, nothing will.

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