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Katech Air Attack Corvette Z06 - A Loss For Words

Two Turbos And 1,000 HP--What Else Do We Have To Say?

Barry Kluczyk Apr 1, 2009
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We auto writers take more than a little pride in our work, despite omnipresent deadlines that not only keep a fire lit under our seats, but blow flames up our--well, you get the idea. Nevertheless, we're constantly flinging open the thesaurus for insightful descriptors that convey the look, feel, and driving experience of cars you're only seeing in print. It's clever stuff like "more torque than an aircraft carrier with a stroker motor."

Obviously, it ain't all gold, but we try. And for better or worse, we're hardly ever at a loss for words. That changed recently when we got a look at Steve Gilliland's yellow Z06. Here's the bottom line: twin turbos, 1,008 hp, and 827 lb-ft of torque. That says it all, right?

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Sure, we could go on about the trick engine combination--although it's surprisingly straightforward--and weave in hyperbolic comparisons between Gilliland's Corvette and, say, the Space Shuttle at launch, but really, what's the point? If you know anything about the Corvette Z06, you know it weighs somewhere between 3,100 and 3,200 pounds. Tack on the few extra pounds for this car's turbo system and some of its other enhancements, and it's tipping the scale at what, 3,400 pounds? Maybe 3,500?

Even math-class washouts like us don't need to spend much time pecking at a calculator to figure out that the power-to-weight ratio of this car is something akin to Bruce Banner after someone cut him off in traffic. No, we like to think of our readers as a savvy bunch who don't need us to point out the obvious.

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If pressed, we'd report that Gilliland--an Oklahoma resident in the oil-and-gas business (a good business to be in these days)--sent the car to Katech in Michigan, to have it built into a purposeful, track-only weapon. It was a shrewd plan, as the finished product looks and performs more like a street-going show car than a down-and-dirty road-course siege weapon. In fact, the competition is likely to take one look at the car and conclude that it's nothing more than a fat-fendered poseur that's just going to get in the way of their sponsorship decals and tow rings. They'd be very wrong.

Again, words fail. Because while "sleeper" is hardly what we'd call a yellow Z06 with a wide-body kit, carbon-fiber rear spoiler and front splitter, and coffee-can-sized exhaust outlets, what other term is appropriate? In fact, a look under the hood reveals nothing more than a painted intake and Katech's trick valve-cover/coil-relocation setup. The turbochargers are buried in the chassis and completely hidden from view. Even when running, the barking exhaust masks the characteristic turbo whistle at idle and low speed.

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Simply put, in its intended environment, this monster Vette doesn't look the part. It's like a guy in a business suit getting a dunk past Kobe Bryant. That's what Gilliland was looking for (he's got other Corvettes for driving on the street), and that's what Katech delivered.

A Thousand And Then Some
Achieving 1,008 hp is never easy, but we were surprised at how difficult it wasn't. Katech started with its Air Attack 7.0L combination, which combines lower-compression pistons and a strengthened bottom end to withstand the pressure of forced induction. In this case, the LS7 block features a Lingenfelter main-stud girdle over a Callies Dragonslayer crankshaft. Attached to the crank are a set of Carrillo forged H-beam connecting rods and Katech's own forged, 9:1-compression pistons. Friction-reducing coated bearings are used throughout.

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Katech also designed the camshaft grind to benefit the force-fed 427 engine and prepped the already high-flow factory heads with Inconel exhaust valves, stiffer valvesprings, and titanium retainers. Premium ARP head studs ensure adequate sealing under boost. Interestingly, the camshaft specs were tailored to the specifications suggested by a computer cam-modeling tool, which hazarded that the engine would make 990 hp. Looks like Katech got its money's worth on that program.

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An APS twin-turbo kit uses a pair of Garrett GT3582R ball-bearing turbochargers (61.4mm inlet/82mm outlets on the compressor; 68mm turbine) and mounts them low on the engine. Careful tuning enables the setup to deliver 12 pounds of boost on 100-octane gas and 15 psi when the engine is indulging on top-shelf 105-octane racing fuel. An Apex-i AVC-R boost controller also helps keep a lid on runaway pressure, limiting boost at certain rpm levels and within the various gears of the six-speed box. As we mentioned, the engine combination dyno'd at 1,008 horses and 827 neck-tugging lb-ft of torque.

Torque is sent to an RPM Level 5-prepped Tremec transmission via an Exedy triple-plate carbon clutch and an LG Motorsports carbon-fiber driveshaft. From there, it's channeled to a Quaife differential and stronger 300M-alloy axleshafts. That tremendous twisting power finally meets the road on Pilot Sport-wrapped HRE 19x12.5-inch wheels--with 18x10-inchers and matching Michelin rubber up front.

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To absorb the powertrain's output and give the car suitable on-track reflexes, Katech also worked on the suspension. Body roll is reduced to virtually nil with the wide tires and Pfadt Race Engineering's competition "Pfatty" sway-bar kit. Claimed to be up to three times as stiff as the Z06's stock setup, this kit features aluminum arms connected to 4130 chromemoly bars, including a unique straight front bar. Katech also slipped in a set of Pfadt's "pillow blocks"--another term for solid bushings. Some suspension movement is afforded by Moton Club Sport double-adjustable coilovers, while stopping power comes from a Brembo GT system with rotors the size of extra-large pizzas.

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"It handles and drives better than my Ford GTs," Gilliland says. That's right, in addition to the 1,000-horse Z06, he owns two of Ford's factory-blown super cars--as well as three more Z06s, a couple of Kenne-Bell-blown Mustang Cobras, and a few other performance cars. None, Gilliland says, compares to the visceral thrill delivered by the turbocharged Corvette.

"It's hard to describe how exciting the performance is," he says. "It pumps up your adrenaline and puts a grin on your face like nothing else. It's incredible."

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Wide Body, Trim Cabin
If you've ever visited Katech's shop, you could be forgiven for thinking Chevy offers the Z06 in only one color. Still, Gilliland's example stands out from all the other yellow Katech Vettes with a full complement of exterior enhancements from AC Products and MTI Racing. These include AC's wide-body kit, Magna-Extractor hood, and carbon-fiber front splitter. MTI, meanwhile, supplied one of its carbon-fiber rear spoilers. The swollen fenders nicely cover the wider tires, and the combination of yellow and exposed carbon-fiber weave is accented nicely by the mirror-finish HRE wheels.

Like we mentioned, Gilliland intends to race this thing, and while we're all for getting your money's worth out of a 1,000hp LS7, it's hard to think of those gorgeous finishes getting scuffed up or discolored by heat. The same goes for the well-executed interior, which is trimmed in yellow-and-black leather, with suede-like Alcantara used on the A-pillars and headliner.

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Caravaggio racing seats replace the stock Z06 units, and Schroth six-point camlock harnesses are anchored to a harness bar. Additional cabin upgrades include an Alcantara-trimmed three-gauge A-pillar pod that's filled with Defi exhaust-gas temperature and fuel-pressure gauges, as well as an AEM air/fuel-ratio instrument. And to keep tabs on the engine's performance on the track, the gauges are equipped with data-logging capability.

With a car whose performance defies adequate description, it's even harder to sum it up at the close of this story. We've sampled some truly fast, well-built Corvettes in recent years, but Gilliland's is something else entirely. It's an envelope-pushing blend of street-car swagger and race-car capability. Oh, and it has more horsepower than a stable full of mutated Clydesdales drinking from a Red Bull-filled trough.

What, no good?



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