The number 1,000 has a nice ring to it. There's the Mille Miglia race, referring to the 1,000 Roman miles from Brescia to Rome and back. There's the list of 1,000 Things to Do Before You Die. Note, too, that the positive descriptor "grand" also refers to the number 1,000. And we all know how a picture is worth a thousand words.
Just look at the photos of Rick Turnbull's C5. That massive Magnuson high-rise hood barely covers a corral of more than 1,000 rampaging horses. It wasn't always so, though, as his Vette has gone through an extensive buildup, and it's not the first time we've documented this 10-year grand scheme. (See "Flight Time" in our Dec. '06 issue.)
We tripped over the car again at last year's Mid America Motorworks Funfest in Effingham, Illinois, while searching for a worthy powerplant to highlight as the Best Engine in the show. That impressive 1,000hp number on his display board jumped out at us, just as we were beginning to wonder if we'd ever find anything really serious among all the shiny show engines. Noting all the power adders, we gave it the nod in our recap of the event's various highlights (along with lighthearted jabs about the "Best Elvis" and "Worst Corvette," among other oddities).
In our initial feature on Turnbull, we were duly impressed by the car's 655-horse output. However, there was one unintended consequence not mentioned in that article, one that Vette owners might need to anticipate in their personal lives. His wife, Lisa, explains:
"After the new hood went on, and all the power Rick decided he really needed, I started thinking...hmmm, I should get my own Vette," she notes. "Here's how it happened: Rick asked me to drive the Vette one day, so I hop into the driver seat, and before I do anything, he says to me, 'I need to tell you how to start the car.' That was it-I was out of the car in a flash. If I can't put the key in the ignition and drive away, it's not for me.
"Well, a few days later we were on our way to a car show, and I jokingly said to Rick, 'My own Vette sure would be nice, since I can't drive yours.' Lo and behold, eight hours and $48,000 later, I was driving my brand-new '04 Limited Edition Le Mans Blue roadster!"
Her advice? "So all you guys out there that really want to soup up your cars, be careful. It could end up costing you a lot more than you thought!"
Anyway, let's get back to what it took for Turnbull to elevate the horsepower from a healthy 655 horses to an outrageous output of 996 hp at the wheels (1,170-plus at the flywheel). To reach this lofty figure, he sought some assistance from Schwanke Engines in Springfield, Minnesota, which obtained a 427 LS7 from GM in exchange for some R&D work. Clearly some conscientious efforts on the mechanicals would be in order, so it was built to handle as much as 25 pounds of boost, with all the top specs.
The makeover included fitment of an Eagle crankshaft, Howard Rods, Mahle pistons, and Hellfire rings, all pumping at 9.5:1 CR. That compression ratio might sound a little high for forced induction from both an ATI Procharger F-1C supercharger (set at 20 pounds of boost) and an NOS 150-rwhp single-stage nitrous system, but the combo has thus far proved equal to the task.
Many other mods were included, including porting of both the GM L76 intake and L92 heads, along with some polishing on the latter pieces. They were also fitted with Comp Cams 918 beehive valvesprings, actuated by the same company's bumpstick (with a heady 238/254-degree duration). A Halltech air cleaner filters the flow into a totally custom electronic fuel-injection setup.
The EFI starts with fuel, lots of it, from double 255-lph in-tank Racetronix pumps provided by Lonnie's Performance Automotive. There's also a set of larger AN delivery and return lines, Motron 80-lb/hr fuel injectors fed through Aeromotive rails, and a Magnafuel pressure regulator. The engine is fed by a single pump until the boost hits a 5-psi threshold, and then the second pump is activated.
The brain behind this configuration is a PCM reprogrammed by John Boos of Boos Performance in Zimmerman, Minnesota. (Boos also helped Turnbull with the engine install.) The parameters consisted of a basic tune for street driveability, then data collection and many more street trips gathering more data and retuning. Last, but far from least, this wild C5 was chained to the dyno for the final tune at wide-open throttle.
To ensure that the blower fills those big lungs at full chat, A&A Corvettes included an eight-rib beltdrive system, along with a Cartek flip-drive system. Turnbull acknowledges the critical importance of all the foregoing engine upgrades, without which the package surely wouldn't survive.
"High horsepower does not come without its issues," he admits. "Some of the hurdles encountered included developing an adequate fuel system, belt slippage, crankcase pressurization, cooling, and traction." But with the help of the Internet and aftermarket manufacturers, all of these issues were resolved to his satisfaction.
Venting the byproducts of the engine's extreme combustion are a set of ceramic-coated American Racing Headers measuring 1-7?8 inches, 3-inch pipes with high-flow cats, QTP electric cutouts, and a Billy Boat bullet exhaust. A DeWitts radiator and a TPIS oil-cooler system keep engine temps in check.
A SPEC 3+ clutch transfers flywheel output to the stock transmission, which is reinforced with a DTE transmission brace. The driveshaft is a factory piece as well, but enhanced with an Elite Engineering tunnel plate. Ditto on the 3.42 rearend, which benefits from a Pfadt axle brace.
This much output also demands some suspension tuning, so Turnbull bolted on a C5 Z06 sway bars at each end, with C6 Z06 shocks in the front and QA1 adjustables in the rear. C5 Z06 cross-drilled rotors and Hawk ceramic pads beef up the braking system. Credit goes to both Boos and Malik's Auto Care for the drivetrain and chassis setup.
The rolling stock consists of Cragar SS rims (17x9 front, 18x12 rear), rolling on BFGoodrich T/A KDW rubber (245/45R17 and 335/30R18, respectively). For strip duty, Turnbull throws on a set of Mickey Thompson 345/35-18 ET Drags. Lewis L5 flared rear fenders-painted in Arctic White by Collision Masters of Crystal, Minnesota-provide an extra measure of bodywork to cover those big meats. Turnbull personally laid on the custom black striping.
He's also laid down some big, black stripes on the asphalt. "The Mickey Thompsons hook up really well in all the gears but First, so as a result there are no high-rpm launches, which would just smoke the tires," he admits. "After that it's just hold on, as my best unofficial quarter-mile time is 9.2 seconds at 152 mph.
"With this engine, 20 pounds of boost, and nitrous, the car is an absolute monster. No use using it to go sightseeing, as it's all a blur. When I take my friends for a ride and stomp on it, they start acting like children, screaming at the top of their lungs."
In the cockpit, Turnbull also added Autometer's fuel-pressure gauge, boost-pressure gauge, and shift light. Other mods included an iPod adapter and raised decals on the steering wheel, passenger airbag, and doorsills, plus nitrous control switches and an engine-specification plaque. In all, the only original parts left on the car are the frame, some of the interior, the trunk lid, the doors, and the front fenders. Everything else has been breathed on by Boos, Turnbull, and the rest of the guys mentioned, mostly within the last couple years.
All these efforts have paid off, as Turnbull has garnered more than 60 trophies at numerous car shows. The car was also chosen for a Celebrity Choice Award at last year's Funfest, by former Corvette Chief Engineer Tom Wallace.
"Having Tom choose my car was a huge honor especially considering all the time, effort and money I have put into the build," Turnbull notes. Which wasn't expected, but fits right into his Grand Scheme. vette
|Heads||Ported and polished L92 aluminum|
|Camshaft||Comp custom hydraulic roller|
|Pistons||Mahle forged aluminum|
|Crankshaft||Eagle forged steel|
|Rods||Howard forged steel|
|Intake Manifold||Ported L76 composite|
|Power Adders||ProCharger F-1C supercharger, NOS 150-rwhp nitrous system|
|Fuel Pumps||Dual Racetronix|
|Fuel Injectors||Motron 80-lb/hr|
|Engine Management||Stock PCM with Boos Performance tuning|
|Maximum Boost||20 psi|
|Exhaust System||Ceramic-coated 17?8-in American Racing headers, 3-in pipes, QTP electric cut-outs, Billy Boat bullet mufflers|
|Transmission||Stock T56 six-speed manual with DTE brace|
|Front Suspension||C5 Z06 Sway Bar, C6 Z06 Shocks|
|Rear Suspension||C5 Z06 Sway Bar, QA1 adjustable shocks|
|Front Brakes||C5 Z06 cross-drilled rotors, Hawk ceramic pads|
|Rear Brakes||C5 Z06 cross-drilled rotors, Hawk ceramic pads|
|Wheels||Cragar SS; 17x9 (front), 18x12 (rear)|
|Front Tires||BFG T/A KDW 245/45R17|
|Rear Tires||BFG T/A KDW 335/30R18 (long-distance driving), Mickey Thompson ET Drag 345/35-18 (daily driving and racing)|
|Miles Driven Weekly||Varies|