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Electric C4 Corvette - Volt Vette

Could This Be The Vette Rod Of The Future?

Jake Weyer Dec 29, 2009
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There's a lot of speculation these days about the future of the automotive hobby, especially when it comes to performance. Corvette enthusiasts have enjoyed more than a half century of tire-shredding internal-combustion power, but the push for hybrid and electric vehicles in recent years is enough to prompt the question: What's next?

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Michael Shoop of St. Louis Park, Minnesota, might have the answer. Shoop is a Corvette guy from way back. He restored a '63 roadster to get over an ex-girlfriend in his mid-20s and later revived a '71 454ci Stingray-he's got an extra front bumper from that car hanging as modern art in his living room. Michael sold both Corvettes in the late-'70s so he'd have enough cash to live off while developing his nature photography business, but they wouldn't be his last.

Even back then, Shoop was fascinated with the idea of an all-electric car. He had always wanted to build one and when gas hit $4 a gallon in 2007, he decided it was time. He made a deal with his wife to spend less on the project than the cost of a new Toyota Prius, which was around $32,000 at the time, and he started hunting for a car. In the beginning he wasn't sure what type of vehicle to go with, but he knew he wanted something with style. Michael said, "My dad gave me this coffee table book on the first 50 years of Corvettes. And I was searching all over trying to figure out what car to convert because when you decide you're going to convert a car to electricity, choosing the right car is really important."

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As Michael puts it, if you hate Edsels and you convert an Edsel to electric power, you're still going to hate the car. Simple enough. So what car would he be willing to spend undoubtedly countless hours toiling over in his pioneering conversion attempt? "From the book I discovered that the C4 Corvette didn't weigh any more than my Saturn, and with the clamshell hood and whatnot, I thought I could get in there fairly easy." Plus, the car looked cool, so the decision was made. His electric car would be a Corvette. Michael soon plunked down $7,400 for a clean, 109,000-mile '87 coupe with an automatic transmission and 3.07 gears. He recorded a solid 30 mpg driving the car as it was, but its gas gulping days would soon be over.

After much research and guidance from the Electric Auto Association and several electrical engineers, Shoop devised a plan that involved 13 lead-acid batteries fueling a 240-pound, 11.45-inch diameter electric motor. He shares that electric car folks talk in terms of motor diameter more than horsepower and an extra inch can make a huge difference. He originally planned on a nine-inch motor, but decided to go with the larger diameter so the car would have no trouble performing at freeway speeds and beyond. The motor Shoop settled on is called the TransWarP11 and is fitted with a double ended armature shaft so it can both drive the car as well as the alternator and accessories. It's also equipped with a TH400 tailshaft housing allowing it to bolt right up to the driveshaft without a transmission. Another convenience is the motor's ability to run at different power levels, which Michael can dial in using a palm pilot connected to an on-board computer. He said the motor will make roughly 100 hp at 92 volts, 200 hp at 156 volts, 400 hp at 300 volts, and 800 hp at 600 volts.

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Right now, the Corvette's 13 old-school lead-acid batteries limit it to 156 volts. Newer, lighter, and more powerful battery technology hasn't come down in price enough yet to make it feasible for the backyard builder on a budget. When it does, Shoop might make a swap, but for now he's focused on testing the car the way he and his crew meticulously built it.

The group fabricated a frame for the motor that fit in the stock motor mount holes and strategically placed the batteries front, center, and rear to balance the car as close to stock as possible. Michael had to cut the rear bulkhead to fit one of his homemade wood and carbon-fiber battery boxes, but the car was otherwise largely unaltered. Incredibly, without any suspension modifications, the car's stance is indistinguishable from stock. A roughly 200-pound weight gain makes for little more bulk than the average passenger.

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Other modifications include a 144-volt battery charger (with a boost transformer to up the voltage), an electric power steering pump, a custom driveshaft that can handle the torquey motor, two 1,500-watt heaters and several battery heating strips for the cold Minnesota months, LED tail lights, and despite a skeptical seller, a set of 4.88 gears. "He said those gears are too tall for an electric motor; it won't move at all," Shoop said. "But he's a Corvette guy, not an electrical engineer."

Shoop has been through plenty of frustrating moments throughout the build. So far he's managed to keep most of his hair despite broken U-joints, failed power steering, battery-heating strips that burnt his battery boxes, blown fuses, and a too-small DC-DC converter needed to convert some of the car's 156 volts to power the headlights, fans, etc. The latter problem was fixed by using the converter to charge a marine battery that now handles the 12-volt stuff.

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Michael uses the Volt Vette, as it's become known, for almost all of his daily driving. He's racked up more than 2,500 miles on the car so far and had it up to 80 mph on the freeway. Though he hasn't tested its range, he estimates it'll go 40 miles on a full charge with a light foot. But it's hard to keep a light foot in a Corvette, especially when power isn't rpm-limited. And even if the horsepower isn't incredible, the car handles like it should, which is enough to give him an ear-to-ear grin when coasting through the curves. With no transmission, the Corvette will glide forever. "I just go cruising by gas stations and wave."

Though he usually charges the car in his garage, he has plugged it in at area businesses (with permission) for a quick charge more than once. Most people are more than willing to let him do so and it's definitely a conversation starter.

The price tag for the Volt Vette so far is roughly $28,000 and it's still a work in progress. One major component Shoop is still working on is a custom digital dash. For now, he has a gauge that reads volts and amps, a handheld device that measures temperature, and a GPS for speed. The Corvette is complete enough to be plenty of fun. Other than a few subtle "electric" badges, the car looks stock, so its dead silence at stoplights is enough to cause other motorists and passersby to scratch their heads. Under power, the big electric motor whines like the starship Enterprise jumping to warp speed.

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Speaking of warp speed, Michael hopes to get it on a dragstrip soon. "It is fun to drive. It should be interesting when I really open it up." Internal combustion might not be around forever, but Shoop has proven that hot-rodding a Corvette certainly can be.

To track Shoop's progress on the Volt Vette, check out his blog.



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