During development, using Z06s with prototype, ’02 LS6 engines, there were a few clutch failures. The extra 15 lb/ft. torque put enough additional stress on the clutch that GMPT decided to upgrade the pressure plate. Clamp load was increased seven percent. This was accomplished by a change in the self-adjusting system inside the pressure plate. The result is an increase in clutch pressure from 2315 lbs. to 2475 lbs. There is also an increase in pedal effort that was deemed acceptable for a high-performance application such as the Z06.

The ’02 LS6’s additional torque output also had the potential to "bottom-out" the damper springs in the clutch driven-disc during clutch action. Damper spring rate was increased by 1.5 pound-feet per degree and a higher quality steel wire is used. Lastly, the disc flange plate (or hub) thickness was increased by twenty percent, from 5 mm to 6 mm.

The head-up display (HUD), introduced for 1999, is popular with C5 owners–so popular that, since its introduction, sales have been 25-40% higher than expected. Even with that popularity, the Corvette development team has been divided on whether or not a HUD belongs on a car like the Z06 and, in ’01, it wasn’t available. Customer input forced a change.

"It was not unanimous," Dave Hill told us. "There was a faction that felt, ‘We don’t like the reflections from the HUD frame.’ and ‘This is not something you need to make a high performance car.’

"Another faction said, ‘Anytime you can communicate information to the driver with no-eyes-off-the-road time, that’s a driving skill enabler–it’s a driving safety enabler.’

"So, it was dead-even. We wanted the Z06 to have relatively few free-expression choices, so, in ’01, we decided to error on the side of affordability.

"The customer input flipped us over. Customers said, ‘If you’re making a driver’s car, why wouldn’t want to use it? We really request that you do that.’

"We had some little mass offsets here and there that could pay for it. It was clear Z06es were seen as more than affordable for what the customer was getting. The HUD is a driver’s aid. We have a HUD that’s the envy of the industry. The customers are asking for it. We decided to make the HUD standard on Z06 for ’02.

While there have been some unseen changes in the HUD since it was introduced in 1999, what we see on the windshield has not changed. My favorite thing to do with the HUD is set it for speed only and use that for turn exit practice.  Image: Steve Stringfellow.

At first, this writer was not a big fan of the HUD. At a press briefing for ’99 Corvettes, after listening to Dave Hill suggest the it was a road racer’s aid because of its shift light, then testing ’99s at Putnam Park, a road course in Indiana; I came away feeling the shift light was of questionable value because it was too hard to pick out in the HUD display. Last winter, a long discussion with John Heinricy (multi-championship Corvette racer, GM’s Director of Vehicle Dynamics and former Corvette Assistant Chief Engineer) about the Z06, convinced me the reason to have the HUD in a performance driving environment was display of turn exit speeds, the reason being: exit speed is an excellent benchmark of the car’s and driver’s performance in negotiating the turn.

Several months later, on my trip up Glendora Mountain Road at high-warp, I set the HUD in that blue Z06 to display digital speed only. Sure enough, no matter how "busy" I got driving the car; it was easy to see my exit speeds. Ok. Now, I’m a HUD fan.

Those who liked the ’96 Grand Spots will feel right at home in an Electron Blue Z06 with these seats. Image: Author. Click Images for Larger View

The ’02 Z06 wheels are a tiny bit lighter and made by a different supplier using a new process but they carry over the "old" look. Speedline, the Italian company that does the magnesium wheels (RPO N73) to be discontinued at the end of this year, is the new supplier. Speedline is an industry leader in a manufacturing process called "cast-spun" and the new/old wheels are cast-spun aluminum alloy rather than the forged aluminum used in MY01.

The change in source and process was driven by 2001 Z06 production being restricted because of a wheel shortage. The conversion was planned and implemented under pressure from the shortage but it was impossible to ensure the change would come right at the model year break. Because GM was desperate for Z06 wheels, the decision was to keep the appearance consistent. That way, whenever the new/old wheel came available, the break-point would be transparent to the customer and there would be no problem with cataloging different wheel designs in the same model year. As it turned out, the switch will come at the model change.

Speedline’s cast-spun technology and the history of C5 wheel processes are interesting stories related to us by Dave Hill. "In 2000, we went with forged wheels. We wanted more toughness for potholes, underinflated tires or really hard driving where you might strike something hard enough to damage the rim and have an air loss. There could be gradual air loss due to rim damage with the old pressure-cast wheels we had in the beginning of the C5 lifetime.

"Basically, the center section (of the ’02 wheel) is a casting. They take that, spin it and work the material out to the rim so it’s more like a wrought wheel at the outer circumference. This technology gives the center section better shape flexibility–which we can use for styling reasons or to reduce mass–but on the rim, it gives you the a crystal structure having the toughness of a forged wheel without being an actual forging.

"We like this because we can get better throughput, which we need to be able to build more Z06es, and we’ve been able to take some mass out. A set of Z06 wheels is .7 kilos (1.5 lbs) lighter than 2001 forged wheels. That’s a tiny amount of mass, but it’s in the right direction. In 2002, the painted (base) wheels and the Z06 wheel will use this cast-spun technology. It really is the next, new technology that’s the best for making a Corvette wheel.

There are two big changes, here, you really can’t see: 1) a new front brake pad that offers better fade resistance and a slight improvement in decel and 2) the lightening in the spun-cast wheel. Image: Jim Fets/GMPT Click Images for Larger View

"As for the appearance of the new wheel, the customer probably can’t tell. On the back side of the spokes there is some undercutting that makes the wheel lighter but you can’t easily see that. For all practical purposes, they’re interchangeable."