An old maxim goes, "If just enough is almost right, even more is better." For some Vette owners, that applies to their engine's output, as they seek more power and torque for quicker elapsed times and higher speeds on the dragstrip.
You can count Charlie Johnson among that group. His '05 Corvette, which came from Bowling Green with a 6.0L, 400hp LS2, now sports a 7.0L LS7 that's been ProCharged and otherwise modified to send the horsepower and torque numbers over 700.
But we're getting ahead of the story.Charlie bought this car at the outset of the sixth-generation Corvette's production run, and for a very special reason. "I was in the hospital for a month, and I told myself, 'If I get through all these operations and stuff, I'm going right to the Chevy dealership. If my wheelchair fits in the car, I'm going home in a brand-new Corvette.' That was my gift to myself, for getting through all the surgeries."
He found this black, automatic-equipped coupe and had it fitted for full hand controls so he could steer with his right hand while working the throttle and brake with his left. Otherwise, his C6 was factory stock. But not for long. "I drove it stock for less than a month," Charlie says. "I got bored with it. I ordered a ProCharger, and once I got it and felt the power it produced, I said, 'You know what? I want to go faster!'"
Mack Performance in Hialeah, Florida, installed the ProCharger, which turned out to be a pioneering job. As Charlie explains, "Mack Performance had a connection with ProCharger, and I was one of the first three guys to get one on the East Coast back then. I was the first guy with an '05 Corvette with a ProCharger here in Florida."
Once installed and dialed in, the ProCharger bumped the LS2's output by over 100 hp. "When Willie had everything done to it, it was pumping out 520 rear-wheel horsepower," Charlie says. "He did a nice little tune to it, and I was ecstatic."
That force-fed LS2 turned Charlie's Vette into an 11-second car that pulled away from his competitors. But eventually, Charlie wanted even more from his C6. "As I saw more people driving 11-second cars, I wasn't happy being 'average' again. I wanted to dip into the 9s. I want to run a 9.90 in street trim."
His dream was a car he could drive to the track with the air conditioner on, run 9.90s, then drive home, without any tire changing or trackside thrashing. That meant some major changes were in store for his C6.
Charlie's power addition began with subtraction. "I ripped out the original engine and ProCharger and sold them on eBay," he says. "I then had Horsepower Sales in Pompano Beach drop in an LS7 crate engine that I bought from Texas Speed & Performance." But that wasn't all. Far from it. "I then went from a P-series ProCharger to an F1A one," he says. "Usually, people go to an E-series one, but I went more extreme." He told his installers, "Let's put the bigger ProCharger on it. This way, if I run 9.90s and I get bored again, I'll at least have the supercharger that I can use to get the car into the low 9s."
Charlie's C6 then went to Next Level Performance in Altamonte Springs, Florida, as a friend recommended Geoff Skorupa's tuning skills once the LS7 and new ProCharger were in. "He fine-tuned it, straightened out all the bugs, and he got that car so it could run 9.80s-9.90s," says Charlie. "He also put a widebody kit on, a bigger brake system, a new driveshaft, and he put on stickier tires in back."
The need for stickier tires-Hoosiers, in Charlie's case-came as a result of the dyno numbers his car was now putting up. "On the dyno, Geoff tuned it to 757 rear-wheel horsepower," says Charlie. "That's when you need every little bit of traction that you can get."
Reliability was also something Charlie was looking for. He says Geoff tuned the LS7 beyond the 757hp level with more boost, but even for Charlie that was "too insane." Instead, "We went one pulley size down, and I was happy with 757 rear-wheel horsepower," he says. "When it was pumping out close to 800, it had the smaller pulley on, and I didn't want any problems with belts slipping and breaking."
He's had no problems with anything else breaking in the engine. "It's a 427 race engine with forged everything inside it, and it was built ahead of time," Charlie says of his LS7. "So, all I had to do was slap the new ProCharger on it to make the engine scream better."
Charlie's also achieved his goal of good drivability with all that power. "It's streetable. There are no problems with it. I can even take it to Connecticut and back." That's something he did twice before with his '05, while it was powered by the ProCharged LS2. "I got 20-something miles a gallon with the cruise control on," he says of his performance on those trips.
Right now, Charlie's very satisfied with his C6. If you're planning to make one hit the 9s, Charlie says that a power adder is definitely the way to do it. "Either with a ProCharger, or twin turbos," he says. "It's your preference. They've both been done. I went with the ProCharger back then, because everybody had a twin turbo, and I'd seen ProCharged cars running some insane times. When I had the choice, I went with ProCharger and never looked back."
Charlie also has some good words about the folks at Accessible Technologies, who make ProChargers. "Those are great guys. I had a problem once, a ProCharger with a bent shaft. I sent it back, they said 'No problem,' they sent me a new one, and it was good to go."
As Charlie's C6 is good to go into the 9s.
Data File: '05 Chevrolet Corvette Coupe
Owned by: Charlie Anderson, Port St. Lucie, Florida
Modified by: Mack Performance, Hialeah, Florida; Horsepower Sales, Pompano Beach, Florida; and Next Level Performance, Altamonte Springs, Florida
Modified production '05 Corvette coupe body
Modifications: Z06 widebody kit, LG Custom World hood
Bodywork: Next Level Performance
Paint: Black basecoat/clearcoat; painting/paint prep by: GM-Bowling Green Assembly's paint shop and Next Level Performance
Frame: Modified production '05 Corvette frame with Lingenfelter rollcage welded to frame; modified production C5 Corvette suspension
Steering: Production GM rack-and-pinion, power-assisted
Brakes: Four-wheel disc, power-assisted
Wheels: Custom black CCW wheels, 18-inch diameter (front), 19-inch (rear)
Tires: Hoosier R6, 245/40ZR18 (front), P345/30ZR19 (rear)
Modified GM Powertrain LS7 overhead-valve V-8
Built by: Texas Speed & Performance, Wolfford, Texas; installed by Horsepower Sales; tuned by Next Level Performance
Modifications: Custom alternator, oil cooler, custom driveshaft
Displacement: 427 cubic inches (7.0 L)
Cylinder heads: Custom Texas Speed & Performance Stage 3
Ignition: Modified production coil-on-plug
Induction: ProCharger F1A supercharger (10 psi)
Exhaust: Dynatech headers and Flowmaster exhaust
Horsepower: 769 @ 6,150 rpm (rear wheel measured on dyno)
Torque: 704 lb-ft @ 5,000 rpm (rear wheel measured on dyno)
Modified '05 Corvette automatic transaxle
Modifications: Custom 3,200-rpm-stall converter, two fluid coolers, and factory shifter; DTE rear gears
Final drive ratio: 3.42:1
Modified production '05 Corvette
Modifications: Lingenfelter rollcage, four-point G-Force harnesses on driver's seat, full hand controls for throttle and brakes
Seats: Production '05 Corvette, upholstered in black leather
Carpets: Production '05 Corvette nylon cut-pile