Code Breaker

Also from Issue 61

  • The 1964 coupe
  • Best Corvette Buys for $8K
  • GM’s Performance Build Center
  • 1968 Big-block Coupe
  • 1966 Coupe
  • American Le Mans Series Report
  • How-To: Tie-rod Ends
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The Z07 package, which adds a not-insignificant $9,495 to the bottom line, brings a Z06 several important steps closer to its ZR1 big brother by raiding that top-of-the-line Corvette’s parts bin. Easiest to spot are the wheels. Spun-cast for Chevy by Speedline, these 20-spoke alloys measure 10 × 19 inches at the bow and 12 × 20 inches at the stern (up from 9.5 × 18 inches and 12 × 19 inches, respectively) and are painted the same Competition Grey color. As on the ZR1, they are shod with Michelin Pilot Sport PS2 tires, instead of the Z06’s standard Goodyear Eagle F1 Supercar G2 tires (which, by the way, are new and improved for 2011). The Michelins are slightly larger than the Goodyears, sized 285/30ZR19 up front versus 275/35ZR18, and 335/25ZR20 at the rear in place of 325/30ZR19.

The Z07 rolling stock is anchored to suspension that differs from standard Z06 fare in two ways. The biggest change is the inclusion of Magnetic Selective Ride Control (MSRC) shock absorbers. This real-time damping system, which is tuned slightly differently than its ZR1 counterpart because of the Z06’s 158-pound lower curb weight, replaces conventional mechanical-valve shocks with electronically controlled units filled with a synthetic fluid that contains minute iron particles. When an electrically induced magnetic charge is present, the iron particles instantly align with one another, and by doing so they provide increased damping resistance. More current yields more magnetic charge and greater resistance in the dampers, while less current does just the opposite.

MSRC “reads” the roadway an amazing 1,000 times per second and reacts accordingly, increasing or decreasing current to each of the four dampers independently to increase or decrease damping resistance. The system’s 1-millisecond reaction time is so quick that if you encounter a huge pothole at 70 mph, the damper for the wheel that reaches the hole first will have appropriately adjusted before it actually reaches bottom. This remarkable performance makes the shocks incredibly adaptable. This trait allowed Chevy to fit Z07-equipped Z06s with slightly softer springs, improving ride quality and reducing axle hop without sacrificing high-speed stability or increasing body roll. In addition, the MSRC’s two modes of operation—Tour and Sport—allow the driver to tailor the system to his or her driving preferences.

The advantages of MSRC were crystal clear during hundreds of miles of driving on the roads of Sheboygan County. Located in eastern Wisconsin on the western shores of Lake Michigan, this area is subjected to extremely harsh winters. The traumatic effects of repeated freeze-thaw cycles, snow plows and ice-melting chemicals have yielded some rough road surfaces. While the interior of the Corvette was annoyingly noisy at times, especially on concrete roads where the incessant tire hum was repeatedly punctuated by thumping sounds over expansion joints, the Z07 suspension (set in Tour mode) absorbed the rough stuff with aplomb. A standard Z06 would not have fared as well.

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