The Ultimate Expression of the Corvette

By Greg Ary, Contributor Email
Date posted: 05-13-2008

There are lots of tuner Corvettes out there, but few come from actual racing companies. And only one comes from an outfit that has won at the 24 Hours of Le Mans, not to mention every road-racing venue in North America. And that would be the 2008 Pratt & Miller Corvette C6RS.

Blindingly powerful, incredibly sexy and surprisingly refined, the 600-horsepower C6RS is like a Chevrolet Corvette Z06, only better in every way. Really, it's practically a 2009 Corvette ZR1. Just don't call it a tuner car, at least not to Pratt & Miller's face.

"The C6RS is definitely not a tuner car," said Brandon Widmer, Pratt & Miller spokesman. Rather, he says, the Corvette Z06-based C6RS is "a fully developed supercar with a genuine racing heritage."

Turns out, it's a heritage that comes through loud and clear.

Big Noise From Michigan
Based since 1989 in New Hudson, Michigan, Pratt & Miller Engineering and Fabrication is pretty much unheard of outside the racing world. But Pratt & Miller has been GM's unofficial racing team for quite some time, building race-winning versions of the Chevrolet Corvette and the Cadillac CTS-V. The company is most famous for its class-winning efforts at the 24 Hours of Le Mans with the Corvette C5-R and C6.R, plus seven consecutive class championships in the American Le Mans Series (ALMS).

But Pratt & Miller has never built a road car. And it probably wouldn't have built the C6RS if some folks at Chevrolet hadn't asked Pratt & Miller to develop a package that could stimulate the sales of aftermarket accessories for the Corvette. The Pratt & Miller Corvette C6RS appeared at the 2007 SEMA show with Jay Leno leaning on the front fender.

One could say that the project got a little out of control. Though the car starts as a standard Corvette, Pratt & Miller leaves virtually nothing intact during its transformation. Think Mercedes-Benz SLR McLaren, not Corvette hot rod.

"There is not a part on this car you can bolt on," says Pratt & Miller's Widmer proudly.

The Opposite of Stock
The 2008 Pratt & Miller Corvette C6RS might look largely stock, but it ain't. During the transformation, lightweight carbon-fiber pieces replace all the bodywork, the deck lid and the coupe's targa bar. The hood features a huge waterfall vent to help extract heat from the engine beneath. The most distinctive aspect of the Pratt & Miller bodywork is the louvered fenders, a design borrowed directly from the Corvette C6.R racecar.

Wider fenders cover the massive 295/30R18 front and 345/30R19 rear tires, which are wrapped around racing-style, center-lock BBS wheels with 11-inch rims in front and 13.6-inch rims in the rear. As a result, the C6RS ends up 1.6 inches wider than the Corvette Z06. You really notice it from the rear, where the uncluttered rear end with its carbon-fiber aero diffuser makes a standard Z06 look positively puny.

The carbon-fiber front fascia is all business, with two brake ducts per side and a pronounced aero splitter that skims the pavement. No, you don't want to be charging up steep driveways in this car. (Fortunately the C6RS has a lift system to help jack up the nose in such cases.)

Unexpected Refinement
Likewise, the C6RS's interior is not the industrial zone you see in a racing car but instead a typical Corvette interior, only with soft, hand-stitched leather and unique Lear-built seats.

But the most significant change inside involves something you can't see or feel, but rather can hear. You see, all the standard Corvette's regular acoustic insulation has been replaced by 80 pounds of thick, multilayer Dynamat, even inside the door panels and under the cargo floor.

The result is a cabin virtually free of random ambient noise — well, aside from the sound of the engine. Imagine the exhaust rumble of a 500-cubic-inch V8 piped into your ears with noise-canceling headphones — pure power and nothing but.

The Heart of the Matter
We've tried to be good so far and pretend the Pratt & Miller C6RS is a reasonable automobile for adult drivers, but the whole reason to buy a car from a racing technology company is really the engine, isn't it?

Glove-soft, French-stitched leather is nice, but you might as well be sitting on a pile of newspaper once you press the C6RS's start button and 8.2 liters of race-bred fantastic-ness comes to life.

It comes from Katech Engine Development in Clinton, Michigan, another partner in GM's racing efforts. The architecture is the same as the Corvette Z06's 7.0-liter LS7 V8, but this new aluminum block has been stroked to 4.5 inches, while the Nicom-coated, liner-less cylinders effectively offer a 4.2-inch bore. The result is an all-aluminum, 500-cubic-inch (8.2-liter) V8 that produces a very big noise, which is what you'd expect from 600 hp at 5,800 rpm and 600 pound-feet of torque at 4,600 rpm.

We had our chance at the Pratt & Miller Corvette C6RS at Spring Mountain Motorsports Ranch in Pahrump, Nevada, and we all but forgot our names when we first stabbed the throttle. The redline is just 6,200 rpm (down from the Z06's 7,000 rpm), thanks to all the piston speed from this long-stroke V8; and it comes up mighty quick when you're charging through the gears.

How quick is the C6RS, say, to 60 mph? "We know it's in the low 3s, but we have nothing official," Pratt & Miller's Widmer says.

Well, it feels that fast. We weren't able to test the C6RS formally (nor even drive it on public roads, we must admit), but we spent a full day in the Z06s of the Spring Mountain Advanced Driving Academy, and the C6RS felt faster — much faster.

Additional satisfaction comes courtesy of the C6RS's blueprinted six-speed manual transmission. The terrifically precise, short-throw shift linkage works with a surprisingly light-effort, progressive-action clutch so quick shifts are virtually goof-proof. The Corvette C6RS makes shifting gears a joy on its own, never mind the 600 lb-ft of torque that's a reward for getting it right.

Power Gets to the Ground
The C6RS also has astounding grip. The suspension is little changed from the Z06's components, but Pratt & Miller has tuned the dampers and an Arvin Meritor Dynamic Height Control system uses air bladders to adjust the ride height. (Raise it an inch for errands to the store or lower it an inch and a half for track work.)

The C6RS feels planted to the pavement and utterly loyal to your chosen line through the corners, thanks in large part to the use of Michelin Pilot Sport 2 Corsa tires that are sticky, yet offer an amazingly compliant ride. As a result, cornering speeds are astounding, but they don't come at the expense of your vertebral alignment. "That was a huge goal for us," says Widmer. "We did not want a racecar-type ride."

But Pratt & Miller did want racecar-type stopping power, and so a Brembo Grand Turismo brake package has been fitted. Six-piston front calipers clamp 14-inch rotors, while four-piston rear calipers work with 13.5-inch rotors. Vented, cross-drilled steel rotors and plenty of cooling through the new ventilation ducts help produce brilliant stopping power, as these brakes show virtually no trace of fade even after three hours of flogging on the track.

Cubic Inches Cost Cubic Dollars
As you might imagine, a list of component upgrades so rife with brand names to make any automotive label-whore salivate doesn't make the 2008 Pratt & Miller Corvette C6RS exactly cheap. The price of the Pratt & Miller upgrades is $186,000, and you still have to supply the Chevrolet Corvette Z06 to start with.

This adds up to a total of $260,000, give or take a few grand. Of course this includes a two-day driving school taught by the legendary Ron Fellows, the ALMS-winning Corvette driver who even had a special-edition Corvette named after him. More important, it includes a two-year/24,000-mile warranty.

Wanna save money? P&M can do the same trick on any '05-or-newer Corvette C6 coupe or convertible. (So far, three cars are built, and seven orders have been taken.) It even offers a package for cars with an automatic transmission. But we're still talking about a quarter-million bucks for a Corvette.

Sure, the C6RS is probably the nicest Corvette in the world, rethought and reengineered in nearly every way, and it transforms the Corvette into an exotic that can hold its own with a Lamborghini Gallardo LP560. We expect that Pratt & Miller's goal of selling 25 C6RSs per year will probably barely satisfy wealthy Corvette racing fans for whom the upcoming Corvette ZR1 will be too common.

What's the ultimate Corvette worth, anyway?

Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.