Point of View

Can a Corvette really have too much power? This supercharged C5 forces the question.

Photo: Point of View 1
October 1, 2009

How do you view things? Are you a glass-half-full or glass-half-empty type? Or do you just throw caution to the wind and overflow the glass? What we have here is the automotive equivalent of a cup seriously runneth over. If you have a new ZR1 in the garage, you best keep it there because this C5’s monster engine puts out 783 horsepower—at the rear wheels, on pump gas. Numbers? You want more numbers? How does a quarter-mile trap speed of 141 mph sound? And that was achieved without using the car’s nitrous bottle, and with an idler pulley that called it quits half-way down the strip. This Corvette also boasts 710 lbs-ft of torque. Yet it’s docile enough to trundle off to the grocery store on a daily basis. It’s like having your cake and eating it, too.

Arizona resident Drew Johnson bought this car as an unmolested 1999 Z51-equipped hardtop in late 2004. It was his first Corvette. While he was impressed with the job Bowling Green had done, he felt that there was room for improvement, especially in regards to horsepower. He approached the crew at Loud Pedal Motorsports, in Chandler, Arizona, and laid out a plan to kick up the power. But before anything could be done, the stock engine had an “incident.”

The Phoenix area doesn’t get a lot of rain each year, but when it does, it pours, and the streets turn into rivers. While driving through an exceptionally deep puddle, some water got Hoovered up into the engine. In short order, internal components became external, and the LS1 was history.

Photo: Point of View 2

This little incident allowed the Loud Pedal crew to start with a clean slate. Into the engine compartment went a 402 cubic-inch Katech block. Knowing that it was going to live a life of forced induction, Johnson issued instructions: “Build something that won’t blow up.” To that end, a slew of forged components were installed, including JE pistons, Callies connecting rods and a Callies crankshaft. Lingenfelter heads brought the compression ratio down to a reasonable 9.5:1.

As for the supercharger, Johnson had a belt-driven Procharger D1SC unit installed. At full chat, the blower pumps out 14 pounds of boost. And as if that wasn’t enough, Loud Pedal also installed a nitrous system, complete with 100-shot injectors. Of course, the fueling system was beefed up—with the kind of power this engine was expected to deliver, fuel starvation wasn’t an acceptable option. Twin Walbro 255LPH gerotor pumps push the 91 test through a pair of race-spec feed lines to a set of Aeromotive fuel rails, which lead to 60-lb injectors. A heavy foot needs heavy fuel.

Photo: Point of View 3

With this much power, having an effective engine oiling system was mandatory. Loud Pedal addressed this concern with the installation of a ported LS6 oil pump. And in case of a supercharger failure, the blower’s lubrication system is self-contained, assuring that the engine won’t starve for oil.

The exhaust system wasn’t ignored. The standard manifolds were swapped for a pair of 1 7/8-inch LG Motorsports Pro Long Tube headers; they exit into a Borla Stinger exhaust. The resulting sound had us looking for the Four Horsemen of the Apocalypse. Even at idle, the Vette’s rumble was powerful enough to make the rearview mirror vibrate like a tuning fork—and we’re talking about the one in the chase vehicle behind Johnson’s car. Once above idle, the exhaust note quickly turns nasty. Then, as the blower comes on, its whine and the fluttering of the TiAL 50-mm wastegate combine to create a brutal sound that scares dogs and frightens small children. Pity we haven’t mastered scratch-n-listen magazine technology, but if you get on YouTube and key in “Drewstein,” you can hear the dyno pull and understand what we mean. If the hair on your neck doesn’t stand up when the revs climb, check for a pulse.

What good is an engine that cranks out a mountain of twist if the clutch doesn’t pass the torque downstream? That’s where the Spec Stage 3+ twin-disc clutch comes in handy. With its full-faced carbon-metallic material, it grabs like a leech when engaged, but pedal effort through the ZO6 clutch cylinder is moderate and eminently livable. Aft of the clutch is an RPM Level 5 6-speed manual transmission, which is capable of staying intact even during spirited shifting. The rear differential holds stock 3.42:1 gears, but the output shafts have been hardened for durability.

Photo: Point of View 4

Durability is good.

The biggest problem with having an engine of this level is getting the power down to the ground. To this end, Johnson went with extremely wide rubber, with 345/30ZR19 Hoosier R6s at the rear. The R6 is essentially a road-racing slick with a couple of grooves to gain DOT approval. It’s a very sticky tire, but even if it were covered in glue, it would not stand a chance against 4,000 rpm and a side-stepped clutch given this car’s torque. The front tires are 275/35ZR18 BF Goodrich KDWs. The rubber is mounted on a set of iForged Aero wheels, featuring a custom combination of matte-finish spokes and glossy rims with a thin red accent stripe to play off the red on the brake calipers. Very tasteful.

Photo: Point of View 5

Johnson felt that the stock Z51 sport suspension was up to the task, so he left it in place. However, he did have Loud Pedal lower it two inches using an aftermarket bolt kit—no wonder the wheel/tire package fills out the wheel wells so nicely. The Z51-spec brake calipers also stayed put, but they now clamp an aftermarket set of slotted-and-cross-drilled rotors with Z06 pads.

Body modifications were held to a minimum. They include a pair of Lewis Five Motorsports rear fender flares and a Spectre Werkes GTR rear fascia with a full-length tail spoiler. A taller hood was needed to clear the supercharger. Its carbon-fiber construction lightens the load on the front tires while the generous vents allow engine heat to escape to the atmosphere. The combination of the wide rear tires filling the flares, the hunkered-down stance and the black paint make this one menacing-looking Corvette.

The interior is stock, with the exception of a nitrous bottle in the luggage compartment and some auxiliary A-pillar-mounted gauges. No roll bar is installed, as Johnson wanted he and his wife to enjoy easy ingress and egress, as well as uncompromised interior space during long drives. Yes, this is not merely a Millennium Falcon on wheels, it’s a road-trip weapon. The week before our photo shoot, the couple spent a long day traveling to southern Arizona, just for a hamburger. With lots of steady cruising at 70 mph, the car delivered 22 mpg, impressive as much for the superb mileage as for Johnson’s restraint. He didn’t hammer it like a fiend, and this Corvette loves to be hammered.

Photo: Point of View 6

When Johnson attended the Bondurant School of High Performance Driving, much emphasis was placed on smooth control inputs. After our time behind the wheel, we can assure you that this Corvette is the poster car for smooth inputs. The car’s turn-in response is almost instantaneous, which makes for sharp handling, but it also demands steady hands and the driver’s undivided attention.

The same is true of the throttle. An injudicious stab on the gas pedal will swing the rear around in a hurry, while at the same time violently slamming you into the seat and generating an expensive cloud of smoke. The secret to gaining real pace in this machine is to sneak up on the power band, making sure the front wheels are aimed straight before the boost comes on. Johnson wanted a package that would allow him to “roll into it like a cruise missile,” and he got it.

Photo: Point of View 7

When the rear tires hook up, this Corvette reels in the horizon at an alarming clip, so much so that you have to look far down the road any time you’re hard on the gas. If you don’t, you’re going to get hurt—fast. Respecting what this vehicle can do is key to keeping one’s hide intact.

It could be argued that this Corvette has too much power. Even with those enormous Hoosiers out back, it has a hard time putting all 783 horses to the pavement. Yet, in the higher gears the car lunges forward so explosively, so addictively, we wouldn’t want any less output. We even caught ourselves imagining what it would be like if Johnson were to have even more ponies extracted from the V8.

Power truly is corrupting.

On the other hand, the point can be made that this Corvette has just the right amount of horsepower. Despite its extensive engine mods, the car is still docile around town, albeit somewhat on the loud side. It’s equally at home being driven to the store as it is being raced down the drag strip, which is exactly how Johnson wanted it. In the end, the question of what constitutes too much power just depends on your point of view.

Also from Issue 52

  • Hand-controlled 2007 Z51
  • 1961 restoration
  • Market Report: C4
  • Tech: Carbon fiber
  • 1990 Lister Corvette
  • 1958 Lister Corvette
  • 1969 L88 convertible
  • Racing: 24 Hours of Le Mans
  • How-To: C3 trailing arms
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