1999 Chevrolet Corvette - Juiced Coupe

Chris Weber's Nitrous-Injected '99 FRC Is A Low-Profile Giant-Killer

Eric Orban Sep 2, 2008 0 Comment(s)
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Corvettes are hardly regarded as subtle, graced as they are with a shape that embodies the essence of pure performance and instantly conveys their sporting nature. But within the world of modified Vettes, this athletic appearance alone is often not enough. Many owners choose not to keep their horsepower accomplishments a secret, festooning their cars with body kits, dazzling paint schemes, and fender-badge boasts that loudly broadcast their enhanced capabilities.

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The stock-cube LS1 has been enhanced with a carefully selected group of performance parts. TSP heads and a rowdy Comp cam are the major players in this powertrain combo.

Other drivers prefer to forego the cosmetic braggadocio and undertake a more clandestine approach. Chris Weber of Brandon, Florida, is among this group. His '99 Fixed-roof Coupe has an unassuming appearance that doesn't betray the formidable power within. Still, Weber says the car wasn't built to be a sleeper. "You can't call a Corvette a sleeper, [since] they are slick-looking cars." Rather, his aim was to build a fun street car that fit his low-key style.

A lifelong motorcycle enthusiast, Weber had never been a car guy. But after he was involved in a head-on accident in 2002, he decided to leave two-wheeled conveyances behind for the relative safety of performance cars. He's tried out many artificially aspirated vehicles in the short time since then, including a twin-turbo Mustang Cobra and a head-and-cam '01 Z06 with nitrous. "Basically, I get bored with cars, and I like to move on before they need costly repairs," he says. His experimentation has given him a preference for nitrous oxide over forced induction in LS engines, since the super-cooling gas is capable of providing more performance gains for less money in these applications.

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The engine in Weber's FRC comprises a highly effective suite of performance parts, all of which were chosen with an eye toward preserving reliability and daily usability while significantly boosting power. The internally stock block is topped with a set of Texas Speed & Performance Stage 2.5 5.3L cylinder heads. These retain the factory rockers but are outfitted with oversize valves and platinum dual valvesprings. The heads were set up by TSP to complement the specs of the aggressive Comp Cams 237/242 camshaft, which features 0.605/0.610-inch lift on the intake and exhaust sides, respectively. Rounding out the valvetrain are a set of Comp lifters and chrome-moly pushrods.

Intake air enters through an open-element K&N air cleaner and travels through an LS6 manifold fitted with a ported throttle body. The engine's increased fueling demands are met with 42-lb/hr injectors, while the oiling duties have been bolstered with an LS6 oil pump.

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The trick nitrous setup, designed by Weber, boosts the inconspicuous FRC's output to 550 hp and 550 lb-ft torque at the wheels.

In keeping with the car's theme of subtlety, the exhaust system has been designed to scream sotto voce. A pair of TSP long-tube headers feed into a custom mid-pipe and after-cat setup employing Magnaflow mufflers. The tips are actually transplants from a Mitsubishi Evo-likely a Corvette first. The resulting exhaust note has a mellow tone that doesn't divulge the Vette's performance capabilities.

The single greatest contributor to the car's prodigious acceleration is a custom Nitrous Express nitrous system. Unhappy with the inconsistent results he had achieved with the nitrous setup on his previous Z06, Weber wanted to devise a new form of system control that didn't rely on the mass-airflow sensor. He decided to experiment with a unique idea that he'd been considering for some time.

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Matte-black C5 Z06 wheels and rear brake ducts add a hint of aggression to the car's otherwise unassuming appearance.

With the help of tuner Jeremy Formato, Weber set up the NX kit to run off of engine-coolant temperature (ECT) settings at wide-open throttle. The system's fogger nozzle is placed behind the MAF and doesn't use the sensor's readings to enrich the fuel mixture when the nitrous is engaged. The engine instead relies on programmed ECT values to add extra fuel and pull timing when necessary. Inside the cockpit, a potentiometer allows Weber to instantly adjust the ECT values to meet his needs. He can dial in overly rich settings with less timing for lower power or lean out the mix for maximum gains. While Weber has seen this approach discussed theoretically in Internet forums, he's fairly certain that he's the only person to have brought it to fruition.

Naturally aspirated, the Gen III mill puts out 440 hp and 390 lb-ft of torque at the rear wheels, imbuing the Vette with a docile nature that provides for supreme driveability on the street. But with the flip of a switch, the car undergoes a marked personality transformation, pounding out 550 hp and 550 lb-ft torque on the bottle.

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This budget-built C5 is a giant-killer that routinely defeats cars making twice as much power.

Since the Fifth-generation Corvette's factory T56 six-speed could theoretically handle the power output of the German battleship Bismarck, only a Textralia clutch has been added to help deal with the heightened power loads. Weber also installed a Hurst shifter for crisper gear swaps.

Since this hardtop C5 is used as everyday transportation, Weber has kept suspension modifications to a minimum. The car was lowered on the stock bolts, and the OEM setup was upgraded with C6 Z06 shocks and C5 Z06 aluminum sway-bar endlinks. The objective was to ensure that the Vette handled well and provided adequate traction, while remaining comfortable enough to be used as a daily driver. According to Weber, this well-balanced setup can provide plenty of thrills without an overly harsh ride.

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Inside, a ball-knobbed Hurst shifter is the most obvious deviation from stock.

This stealthy shark prowls the Tampa Bay streets camouflaged in an unassuming Light Pewter Metallic hue. With the emphasis on maintaining a low profile, the exterior is devoid of ostentatious body modifications. The original rolling stock has been replaced with C5 Z06 wheels with a matte-black finish. These are wrapped in 265/40-17 Toyo Proxes T1-S tires in the front and 305/35-18 Nitto NT555R Extreme Drag radials in the rear. A pair of C5 Z06 rear brake ducts lend an aggressive finishing touch.

Weber credits his FRC's noteworthy performance to its well-balanced setup, saying, "It pretty much does everything well." The car isn't a straight-line monster, but rather a giant-killer with a whole that is greater than the sum of its parts. With its ability to put its power to the ground, the Vette has bested opponents with twice its power output. Eschewing form in favor of function, Weber has achieved his aspiration of building a daily driven Corvette with exceptional performance.

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