Suspension
Exceeding 1 g of lateral grip is no small feat, but Chevrolet says the ZR1 will do it. How? The role of fat rubber in achieving this peak number can't be ignored, but a sophisticated suspension system allows the ZR1 to shine no matter what the road condition. Though it uses the same basic front/rear SLA setup of other Corvettes (albeit with tweaks like larger anti-roll bars), the big news is the ZR1's use of a retuned version of the Magnetic Selective Ride Control that is optional on base Vettes. Many readers are probably already familiar with this system: by using special fluid exposed to magnetic fields, the damping properties of its shock absorbers can be altered in only thousandths of a second. This allows the system to adapt to driver inputs and changing conditions of the road virtually instantaneously.
Recently upgraded to Gen II spec for the 2008 model year, the MR system (as the engineers call it) is considered by most a near-$2,000 luxury alternative to the Z51 performance package on base Vettes. But for the ZR1, it's been retuned to allow for a top-notch suspension good enough for a supercar--with a ride quality that, although not soft per se, is said to be significantly more compliant than that of a Z06 when set in "touring" mode. A good part of the latter has to do with the MR system enabling the engineers to soften the rates of the composite leaf springs: the front spring is that used in Z51 cars, and the rear uses a modified Z06 spring with a bit less material. "In the past, we engineers had to compromise between ride quality and the way the car handles on a racetrack," says Danahy. "But with the MR system, you get the best of both worlds, as its variable damping allows the system to be tuned both for the track and for the street. [Corvette Chief Engineer] Tom Wallace likes to say this is a good car for going to get bread and milk--and it is. It's really a nice car to drive on the street!"
Delivering the best possible amount of grip to the tires along with a smooth ride is great, but the ZR1 also features a new, previously untapped side benefit to the MR system that is probably of additional interest to GMHTP readers (many of whom are, shall we say, "drag-happy"). Anyone who has driven a stock C6 Z06 surely knows that car's amazing propensity for traction, even from a slow-speed throttle stab. The situation can quickly change on hopped-up cars with aftermarket turbo kits and the like, so it's no stretch to imagine the additional 130 lb-ft (give or take) of blower-induced twist that will be provided by the LS9 would roast meats of any width in similar fashion. The MR system provides one nice solution by automatically detecting a high rate of lift on the front of the car and kicking the damping of the shocks down to around 33 percent, allowing maximum weight transfer to the back tires. Damping rates can then be modulated up to around 90 percent to hold it there as the car begins to accelerate. "So basically it allows the car to sit, squat, and then go. It's like an electronic traction bar," says Danahy. "It works great and we didn't have to engineer any new hardware. We just changed some 0s and 1s!"
In addition to a ZR1 badge, GM adds a new, full-width spoiler to the rear of the car. It looks a whole lot like the popular Genuine Corvette Accessory (or the one installed on the Ron Fellows-edition Z06), but it's different--and fully functional. According to Jim Danahy, "We specifically tuned that spoiler to work with the front splitter on the ZR1. Our development guys don't want to drive the cars if one is on and the other isn't! It really does reduce lift and help balance the car out." | 
The gauge cluster differs only slightly from other Vettes, with a ZR1 logo on the tach and a 15-psi boost gauge just to the right of the speedo (which now reads 220 mph, you'll note). As of this writing, testing to see just how close this car will come to pegging that needle has yet to be done ... | |