Going into the 2010 model year, the Corvette lineup is growing to four models with the revival of the Grand Sport nameplate that slots in between the base and Z06 models. This is the third iteration of the Grand Sport, the first being a run of just five race-ready cars built by original Vette chief engineer Zora Arkus Duntov. The second batch was a run of 1,000 cars built in 1996 to close out the C4 generation. This time around, the Grand Sport is a regular production model and General Motors promises to make as many examples as customers demand.
The first customer bound production examples should be arriving at dealers this week, and the Corvette crew invited Autoblog out to the Milford Proving Ground for a tasting session. Thankfully, when Corvettes and Milford mix, that usually means a visit to the Milford Road Course (MRC), better known as the "Lutz 'Ring." MRC was completed five years ago at the south end of the company's proving grounds and as you might imagine, it's a suitably wonderful place to evaluate Corvettes. We spent the better part of an hour thrashing the Grand Sport around the MRC and came away impressed with this middle child. Read all about it after the jump.
Photos copyright ©2009 Sam Abuelsamid / Weblogs, Inc.
The Grand Sport borrows from its big brother, the Z06, to offer Vette drivers something a bit less hardcore but with similar visual appeal. The front fascia with the center mounted scoop and wider rear fenders are common to the Z06. The front fenders, however, get a new side scoop design unique to the GS with a chrome badge along the top edge. Unlike the Z06, the GS retains the standard steel frame of the base model, meaning it is available in both removable roof coupe and retractable roof convertible bodystyles.
Filling up those wider wheel wells are the same size Goodyear Eagle F1s fitted to the Z06 – 275/35ZR18 in front and 325/30ZR19 at the back. However, the GS gets a unique five spoke wheel design to show off bigger brakes also borrowed from the Z06. The alloys are available in the usual silver and chrome finishes, but the real winner is probably the Competition Gray, especially when contrasted against the white or silver body colors.
GS buyers who fondly remember the 1996 edition will also be able to get the Heritage package that includes a pair of contrasting fender top hash marks in either white, red, gray or silver. Unlike the last version that only got the stripes on the drivers side, the new model sports the markings on both flanks. Heritage pack buyers also get two-tone leather seats with the Grand Sport logo embroidered on the head rest, which is a deal at just $1,195.
For those more interested in functional upgrades, the big news comes with the manual transmission coupe. The GS retains the LS3 engine designation for its 430-horsepower 6.2-liter V8, but three-pedal coupes get the dry sump used on the LS7 (Z06) and LS9 (ZR1). When the lateral Gs start to really build as they do on the MRC, this system really helps to ensure that all of the engine's moving bits in the engine stay well lubricated. Aside from the cast aluminum pan and the reservoir, the only other internal changes are to the front of the crankshaft and the inclusion of a wider two-stage gerotor oil pump, which is needed to scavenge the pan and then pump oil back from the reservoir. The dry-sump LS3 for the GS will henceforth be hand-built on the same line at the GM Performance Center in Wixom, MI that builds the LS7, LS9 and LSA for the Cadillac CTS-V.
The GS also gets the bigger brake package from the Z06 consisting of cross-drilled rotors all around spanning 14 inches in front and 13.4 inches in the rear. The front discs are squeezed by massive six-pot calipers while the rears get four-piston units. Shift-it-yourself GS manuals also get shorter gearing that helps cut about two-tenths off their 0-60 mph times, bringing the stopwatch to a halt in about 3.95 ticks. Given that some 70% of all Corvettes are sold with automatic transmission, it warms our hearts to see the three-pedal Vettes get upgrades that those other folks miss out on.
The last of those improvements and one that actually applies to all Corvette models with a clutch pedal is launch control. We'll describe our experience with launch control separately, but suffice it say that Corvette chief engineer Tadge Juechter emphasized the fact that using the new launch control system "WILL NOT VOID YOUR WARRANTY" – unlike a certain Japanese sports car.
After getting the lowdown on the Grand Sport, it was time to drive. The MRC is a three-mile long, 17-turn road course where, according to test driver and track designer Jim Mero, 97% of every lap is spent under lateral acceleration. To keep things under control, GM had us come into the pits every lap so they could set up a cone chicane on the back straight. The course is designed as an engineering test facility rather than a racetrack and includes two off-camber turns, increasing and decreasing radius turns and even two "jumps" to unload the suspension.
The complaints about the Corvette's interior are well known and don't really need to be re-hashed – but hash away we will. In general, the layout of the controls is fine and the relative position of everything works well. The problem is the materials that, especially in base form, come off as decidedly cheap looking and feeling for a $50,000 car. Compared to a Lexus or Audi of the same price point, the Corvette doesn't stand up. However, it must be remembered that this is not a mid-level luxury sedan, but rather a giant among sports cars. When compared to cars of like performance, the Vette remains an outright bargain. Clearly GM had a budget and a price point to work with and the engineers and designers decided to put the money where it counts first for a sports car. Despite our complaints, it's no Aveo inside, so for the most part we'll give the interior a pass.
The reason we say "for the most part" is the seats. Simply put, they are the one functional aspect of this car that is unacceptable. For a vehicle with the ability to sustain 1 g cornering loads, the bolsters are just not up to the job. We asked Tadge Jeuchter why they don't offer the wonderful Recaros from the CTS-V as an option and it turns out that they simply don't fit. The structural center tunnel doesn't leave enough room for any current off-the-shelf performance seat to fit in the C6 and fixed race seats are out of the question for a production car. Presumably, now that we know a C7 will be coming in just three years, this "little" problem will be addressed.
Once we got all settled in and adjusted so that our helmets cleared the roof, it was time to fire up the LS3. Certainly, compared to a ZR1, the LS3's mere 430 hp and 424 lb-ft of torque might not seem all that impressive. But looking at what else is out there, the GS pretty much matches the twice as expensive Porsche 911 GT3 in performance and most specs, ensuring that it has nothing to be ashamed of. The more modest torque curve means the GS doesn't need a dual plate clutch, but the effort to release the left-most pedal is still relatively light. Take-up is fairly progressive and smooth launches are easy even without engaging the launch control. Operating a Corvette in stop-and-go traffic is generally not a problem, as this is not a car that requires excess slippage of the clutch or a lot of revs to get moving.
The only other car we have driven on the MRC is the ZR1, and that was a year ago. Right off the line coming out the pits and aiming for turn one, the maximum speed we were able to hit before braking is several miles per hour slower than the supercharged supercar. That said, this is still one seriously fast automobile and there's just nothing like the sound of a big American V8 at wide-open throttle. Slowing into turn one, the brakes offered plenty of assurance they were up to the task of dissipating this much kinetic energy, with a firm pedal and precise modulation ability.
The challenges start right from the first turn at MRC as the radius gradually tightens before heading into a drop away left-right combination. The GS makes its massive grip easy to use, even for a someone with limited track experience. Unlike the Z06, which has often been accused of having very abrupt and twitchy breakaway behavior, the Grand Sport does more of a tiptoe over the edge of adhesion. It's easy to feel the back end slide if you give it gas a bit too early coming out of a turn, and backing off brings the tail right in line. If you stay in it, the stability control will eventually nudge the car back into position. Fortunately, the Corvette engineers have worked with Bosch engineers to make sure the stability control allows enough slip even in normal mode to have plenty of fun before it intruding, and even then it doesn't beat you over the head with its heavy-handedness.
The six-speed gearbox in the Vette isn't the slickest unit on the planet, but it gets the job done as long as you don't try to force it. Third gear in particular on the car we drove seemed hesitant to engage if pushed too fast. The steering feel, on the other hand, was superb and gave a precise accounting of the forces building and diminishing at the front wheels as the car changed direction. The Corvette is generally a very well balanced sports car that allows amateur drivers to approach its outrageously high limits without biting them if they make a mistake. But even more experienced drivers can switch the stability control to Competitive mode or even turn it off entirely to truly test their car handling skills.
Corvette buyers who want that extra bit of juice that the Grand Sport offers can get the coupe starting at $55,720 with the convertible going for $59,530. That's only about $6,000 more than the base car and nearly $20,000 less than the Z06. This may be one of the best performance bargains on the road even if its seats do suck. Zora would be proud.
Photos copyright ©2009 Sam Abuelsamid / Weblogs, Inc.