VETTE magazine was recently invited to Texas Motor Speedway in Fort Worth to get acquainted with the 638hp '09 Corvette ZR1. Our on-site hosts were Texas Driving Experience Instructor Don Barnes and Corvette Vehicle Dynamics Engineer Jim Mero, who was on hand to wring out the test cars beyond what our limited driving skills would allow.
Mero, you'll recall, is the man responsible for throwing down a stunning 7:26.4 lap on the Nrburgring in a preproduction ZR1, a feat documented earlier this year in a widely circulated Web video. Just prior to heading onto the course, the veteran test driver offered the following appraisal of the car's performance capabilities: "This thing is the fastest vehicle you've ever been in. Are you ready for what it's got?" Having crossed paths with some of the most radically modified C6s in the country, we thought we knew what to expect.
We were mistaken.
In just seven seconds, we accelerated from 0 to 100 on the track's tight infield road course, then carved its multiple twists and turns at speeds in excess of 140 mph. After three non-stop hot laps, we paused for a few moments to catch our breath and process our radically altered notions of what factory Corvette performance can entail.
Those tasks accomplished, we then sat down with Tadge Juechter, vehicle chief engineer (Corvette and Cadillac XLR), to get the behind-the-scenes story on the fastest production Corvette in history.
VETTE Magazine: What were your first thoughts when you were given the ZR1 project?
Tadge Juechter: My first thought was, Wow! They want to do this?
VM: Were you given specific instructions on what to accomplish, or did you define the goals within the engineering department and then sell them to the corporation?
TJ: Our goals were totally our own [Team Corvette's]-namely, build the best Corvette possible for a $100,000 price point. [The car would have] more acceleration, braking, and cornering, but also more comfort, and [it would] retain the utility of a daily driver.
VM: How many engineering team members were responsible for the ZR1?
TJ: The engineering team started with just a handful working in secret but grew to a few dozen as the car moved toward production as an approved program.
VM: Is the ZR1 an America-only success story, or did GM teams from across the globe participate in its development?
TJ: The ZR1 was engineered primarily in North America, but we partnered with some of the best companies in the world, [including] Michelin from France and Brembo, [which is] based in Italy.
VM: Was the LS-series engine the only one you considered for the ZR1? Did you look at alternate displacements? What about a big-block-motor? Was a front-engine layout the only option you considered?
TJ: We talked about the big-block but felt it would be too heavy, and we wouldn't meet our goals for mass and weight distribution. As an advanced version of the Z06, the engine had to remain in the front of the car. All-wheel drive would have torn up the structure and made the car much heavier. We looked at a couple possible displacements, settling on 6.2L as [embodying] the right balance of power and durability.
VM: As was the case with some of the vintage 427s, was consideration given to making the ZR1 an off-road-only vehicle?
TJ: No, the ZR1 was always conceived to be a road car that happened to be extraordin-arily fast and capable on the track. Sales vol-ume of off-road-only variants would be too low to make an acceptable business case.
VM: What components of the ZR1 gave you the easiest validations? The hardest?
TJ: The aluminum frame originally engineered for Z06 duty stepped up to the higher loads and thermal stresses admirably, causing us few headaches. The LS9 engine has also proved to be exceptionally robust, making us comfortable in offering the same 100,000-mile powertrain warranty that other GM products have. Areas that challenged us until the very end included brake cooling, the intercooler circuit, and the exposed carbon-fiber parts.
VM: Did you consider a sequential manual transmission for the ZR1?
TJ: No, the packaging of our rear transaxle makes the use of other transmissions very difficult. A sequential trans would not have been appropriate in an on-road car.
VM: In terms of development, what percentages of your engineering resources were dedicated to engine, driveability, and safety issues, respectively?
TJ: That's impossible to quantify. I mean, for example, are huge brakes a performance, driveability, or safety feature? All of them, of course.
VM: Please tell us about your first drive in a test ZR1, and your first drive in a production model. What were your impressions? Did the vehicle change much between development and production?
TJ: The vehicle changed tremendously. Engine power, ride smoothness, exhaust sound, steering calibration, and braking performance all improved as we moved through the development process. The first prototypes could be described as underwhelming. The finished product lived up to our philosophical battle cry of "shock and awe."
VM: In order of importance, what were the five most significant engineering challenges in designing the ZR1?
TJ: There were so many, and it's too hard to quantify. Thermal management (engine, induction, and fluid cooling); driveline durability (aside from the engine); brake cooling (even though we have oversized ceramics, we still have to route cooling air to them without penalizing lift or drag); and the clearcoated carbon panel's surface and appearance quality all come to mind.
VM: What challenges did you face in integrating ZR1 production into the Corvette assembly line in Bowling Green?
TJ: The ZR1 builds much the same as the other Vettes. Some of the new cooling circuits were a challenge to assemble.
VM: If you were a ZR1 owner, what modifications would you make to improve the car's performance? What mods would you suggest against?
TJ: I would not modify the production car. It is a very balanced design as produced, and almost any change could void the warranty.
VM: Can the ZR1 be serviced at any GM dealership, or are there trained, regional centers that handle service issues?
TJ: There are numerous certified Chevy dealers that can service the car, but not all of them [can].
VM: Would you ever consider building a mid-engine Corvette or ZR1, or an all-wheel-drive one?
TJ: Never say never, but there are huge compromises with either.
Check out next month's issue for exclusive dyno, dragstrip, and road-course tests of the incredible new ZR1. Until then, you can find all the latest ZR1 info on our website, www.vetteweb.com.
Who is Tadge Juechter?
Tadge Juechter was appointed vehicle chief engineer of the Chevrolet Corvette and Cadillac XLR in July 2006. He currently spends his time working to continuously improve the current models, as well as planning the features and technologies under consideration for future models. With such responsibility, Juechter works closely with Tom Wallace, vehicle line executive and global chief engineer of GM's Performance Cars.
Juechter began his career with General Motors in 1977. Prior to his work on Corvette, he held a number of engineering positions in manufacturing, product design, research and development, and vehicle development.
In April 1993, Juechter was named total vehicle systems engineer for the fifth-generation (C5) Corvette program, where he became involved in all aspects of the cre-ation of the new-for-'97 model. He was also instrumental in bringing the C5 Z06 to fruition. In 1999, he was promoted to assistant chief engineer, and he held that position throughout the development and launch stages of the sixth-generation (C6) Corvette.
Juechter received a Bachelor of Science degree in mechanical and aerospace engineering from the University of Rochester in 1979, and he earned an MBA from Stanford University in 1986. During his off-hours, he enjoys running, biking, skiing, and touring the USA in Corvettes.