UPGRADING A CORVETTE’S PERFORMANCE often puts an owner on a slippery slope. More power usually leads to even more power, and street cars slide into race-car territory. It happened to David Busch, owner of Loud Pedal Motorsports, Inc, in Tempe, Arizona. He decided he wanted to increase the horsepower of his sixth-gen Z06. One thing led to another, and before he knew it, he had more than doubled the car’s power output. Dubbed Z0666, the Corvette is like the Four Horseman on four wheels.
Busch got into Corvettes like many have, with a friend lending him the keys to one—in this case, a red C3 convertible. In 2000, Busch bought a Corvette of his own: a new C5 convertible. At that point, he knew that Chevrolet’s sports car was going to be a major part of his life. Business needs saw the 2000 go to a new home, but by 2004, another Corvette was in the garage—a 2003 50th Anniversary convertible. The Corvette’s performance impressed Busch, but he felt that with a handful of standard hop-up tricks, it could deliver more of everything. In went a more aggressive camshaft, an aftermarket exhaust was bolted on and the standard tires were swapped out for a sticker set of rubber. Busch was stunned with the results, but the changes only whet his appetite for increased performance.
In 2005, when he heard that Chevrolet was going to be releasing the C6 Z06, he immediately placed his order. Busch and his wife flew to Kentucky to pick up their 505-horsepower machine at the factory, and the twisty roads around Bowling Green were the perfect venue to break it in. Busch swore that he’d keep this Corvette bone stock, as surely 505 horsepower was enough for anybody. Sense where this is going?
After about two years, Busch was itching for a little more power. The same engine and exhaust modifications he’d installed on the C5 were applied to the Z06, and he ended up with 535 horsepower at the rear tires. The exhaust note was burly and commanding, and the engine idled with the lazy lope of an old big block. After founding Loud Pedal Motorsports in 2008, Busch decided to ramp up the Z06’s performance even more as a demonstration of LPM’s engineering prowess. It ended up being a very steep ramp.
The stock LS7 V8 didn’t have the room for power growth that Busch was envisioning, so it was yanked out, and an LSX454 crate engine from GM Performance Parts was installed. As delivered, this mill cranks out 620 ponies—no insignificant increase over a stock LS7. But Busch had “more” on his mind, and the path to “more” is often paved with forced induction. Busch knew that the LSX454 block and LS7 6-bolt heads could handle considerable boost levels, so he approached Procharger about designing a supercharger package that could churn up a lot of boost while still fitting under the OEM hood. The result was the F1D blower, delivering a maximum of 14.5 pounds of boost.
But just bolting on a supercharger and expecting a livable powerplant is an unrealistic proposition. Busch paid attention to the entire package, from engine components to driveline survivability. A Nick Williams 102mm throttle body sits atop a FAST LSXR intake manifold, and 95-pound High Impedance injectors fill the combustion chambers with pump gas.
Other projects in Loud Pedal Motorsports past had used superchargers to help generate serious power, but belt slippage, even with the use of an 8-rib belt, had been an issue. Busch solved this problem on his Z0666 by using an HPE Flip Drive dedicated belt system. Even though the Corvette’s engine reaches its horsepower peak at a lofty 6,200 rpm, the HPE belt is as happy as a clam. In addition, a Ron Davis radiator was fitted, and during the protracted photo shoot, on a hot Arizona day, the temp needle was locked in the lower portion of the gauge.
On the exhaust side of the powerplant equation, a set of LG Motorsports headers and an X-pipe are used, and a B&B Fusion Exhaust system gives the Z0666 a snarling bark that sets off nearby car alarms when slowly shuffling through a parking lot. When the revs come up and the exhaust note soars, the zone of tripped car alarms increases dramatically. Some Corvettes are under-the-radar; this one smashes the radar.
The dynamometer is the device that separates fact from fiction. It can make dreams come true or shatter them just as easily. After the Z0666 was lashed down and its monster engine cranked up, the numbers that spat out of the printer wowed everyone in the dyno room. The Corvette put down 925 horsepower—at the rear wheels! Torque was a massive 889 lbs-ft at 5,000 rpm, with 500 lb-ft being generated at just 2,000 revs. Figuring a 16-percent parasitic loss in the driveline, the beast under the hood was churning out 1,100 horsepower at the flywheel.
GIVEN THE ENGINE’S MASSIVE AMOUNT OF TWIST, Busch had a heavy-duty Textralia Exoskel clutch bolted on. To make sure gear changes could be slammed home with confidence, a B&M shifter was installed. On the suspension front, Busch went with Pfadt’s Level II Drag Racing Package, which includes adjustable coil-overs at each corner, a thicker rear sway bar and a full set of spherical bearings. Rolling stock is a combination of HRE wheels and Nitto NT05R tires. The brakes were left alone.
The interior is basically stock, too, but a harness bar and camera mount have been fitted. A triple-gauge pillar pod provides additional engine-related information, while a Passport 8500 radar detector and laser jammer helps the driver maintain situational awareness. In a vehicle chock-a-block with race-bred components, you want the deck stacked as much as possible in your favor.
When the Z0666 was finished, it was taken to the local drag strip for some evaluation runs, with Loud Pedal Motorsports’ Steve Kleva doing the pedaling. Unfortunately, an engine problem forced him to short shift it into fourth gear and let the tidal wave of torque hurl the car down the strip. When he tripped the lights, the timing slip read 13.5 seconds at 135 mph. It was clear that the car would run much faster, and Kleva was informed that to continue running, a roll cage would be needed. When the car was diagnosed back at the shop, it was found that the ECM had failed, putting the car into limp-home mode. Upon replacing the faulty component, a couple of hard runs in a secluded area revealed that all was well.
WHAT’S IT LIKE TO DRIVE THE Z0666? Glad you asked. First of all, the suspension is firm, but not abusive. Granted, you’re more aware of bumps than you are in a stock Z06, yet you aren’t reaching for a kidney belt. But you’re probably more interested in hearing about the acceleration, right?
The overriding sensation you get in the car is that it’s just waiting for the gas pedal to be buried. When that happens, things get crazy, very quickly. The biggest immediate challenge is trying to keep the rear tires from being transformed into smoke. Dancing on the gas and clutch pedals like Fred Astaire is a must. When the Nittos finally bite, it feels like your head is being ripped off. Grabbing another gear, and another, does nothing to diminish the sensation. Between the auditory onslaught and your body being crushed into the seat back, it feels like you’ve hit an IED. It feels like the car is trying to kill you with sheer velocity. This Corvette’s acceleration is frighteningly violent.
Has David Busch reached the limit? There has to be some point when you say “enough,” don’t you think? If the past is any indication, the gang at Loud Pedal Motorsports is already cooking up ways to fry the tires even faster. It’s a slippery slope, indeed.
