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1986 Chevrolet Corvette - May The Downforce Be With You

Team Cheaparral Builds An '86 Vette That Really Sucks

Christopher R. Phillip Jul 1, 2008
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How difficult is it to build an award-winning Corvette for $2,007, using the very same engineering training that speeds products such as Tide and Downy to your local supermarket shelf? Impossible? That's not what the men at Procter and Gamble said when it came time to enter their Corvette into a unique high-performance competition.

"The Cheaparral story is about a group of engineers who work for P&G in Cincinnati," says Stoyan Lockar, a P&G Technical Associate Director. "By day, we design and build a variety of world-class machines that make P&G's consumer products [Crest, Pampers, Folgers, and Gillette, to name just a few]. One of the things that we're very good at is making complex machines go faster. To get a competitive advantage in cost, we strive to run our production systems faster than industry standard. As engineers, we take a lot of pride in that. It's similar to taking a car that's basically stock and souping up the performance, then beating others at the track.

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Team Cheaparral becomes the proud new owner of a "slightly blemished" '86 Corvette. The Vette was the victim of a high-speed rollover, with a badly twisted frame and significant body damage.

"This mentality goes beyond our work lives for many of us," Lockar continues. "Since we're gearheads at heart, we also enjoy working and playing with high-performance cars and motorcycles in our spare time. Last winter [2006], inspired by all the build-off shows on cable TV, a group of us decided to see if we could channel our technical skills and innovation in some unique way in the automotive world. We agreed on a few main objectives: Have fun, learn some new skills, get to know each other a bit better, sell our creation at the end, and donate the proceeds to charity."

Lockar and his P&G colleagues studied many possibilities, ranging from building a car from scratch to creating a heavily modified "theme" vehicle. The option that won out in the end included a competitive aspect that really got the engineers excited.

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The interior was in a similar state of disrepair. Fortunately, the car was slated to compete in an engineering contest and not a beauty pageant.

"The project was based on preparing a car to compete in the Kumho Tires/Grassroots Motorsports $2,007 Challenge, [which] consisted of three events: a quarter-mile drag race, an autocross competition, and an appearance-judging contest. Points were scored for each event to determine an overall winner, as well as winners in various classes and categories. The real challenge to all this was that the car and all parts added to it could not exceed $2,007 in total, all of which had to be documented. This challenge seemed to fit very well with our P&G engineering focus."

Its goal established, the team decided on a contest car that would truly challenge its creativity. The candidate was an '86 Corvette purchased from salvage. The Vette had been rolled many times, sustaining extensive damage to the body and suspension system. The engine and drivetrain, however, seemed to be intact. The team decided to tackle the project in two phases: First, it would get the Corvette back in running condition. It would then modify the car to compete in the event.

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Volunteers from Procter and Gamble took on the job of readying the car for the contest. Here, they install a two-post lift specifically for that purpose.

To prepare the Corvette for the competition, the engineers focused on five critical areas: increasing engine power, reducing weight, enhancing cornering capability, improving the car's looks, and outfitting the interior for safety.

The team began by sourcing two $30 turbos from a salvage yard. These were customized to work in the Corvette, an operation that included clocking them for proper geometry, machining a pair of adapter plates, and tweaking the wastegates to reduce boost. The exhaust manifolds were also inverted and modified. Larger injectors were installed to provide more fuel flow, and a custom engine tune was developed and placed on a new E-PROM.

Next, all unneeded parts were removed from the Corvette and sold, reducing weight while also generating much-needed project funds. These items included all the air-conditioning and heater components, the engine air pump, the cruise control, the headlight motors, the power-window units, most of the interior, the mufflers, the spare tire, the jack, the gas tank, the rear bumper-frame assembly, and much more. The parts netted the team over $1,900-$500 more than the purchase price of the car-and removed 400 pounds of performance-robbing avoirdupois.

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A surplus cooling fan from an M1A tank engine provided an amazing 12,000 cfm in a compact, 70-pound package. Thanks, Uncle Sam.

The most radical part of the project involved the team's strategy for improving the car's cornering. Inspired by Jim Hall's Chaparral 2J "sucker" car from the '70s, it developed a plan to generate speed-independent downforce. Doing so would increase tire-to-road frictional force, theoretically giving the car the ability to pull higher g levels in turns. As far as the engineers knew, this concept had never been executed on a production car, and the challenge was intriguing to them.

After extensive calculations and testing with a prototype sled, the team identified the amount of airflow and vacuum required to suck the car to the ground with 1,500 pounds of force (the amount necessary to boost the Corvette's skidpad rating from 0.9 to 1.4g). To stay within budget, it sourced a surplus intake blower from an Army M1A Abrams tank to generate vacuum, powering it with a 33hp snowmobile engine.

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Here's the beer-keg fuel cell as installed, ready to tap into some premium unleaded.

To maintain suction during upward suspension travel, a unique, two-piece skirt frame connected by bellows was developed and installed under the car. Casters attached to the lower frame would maintain a half-inch gap between the skirt and the ground as it raced around the course. Custom front A-arm bushings and adjustable tie-rod linkages were also fabricated and installed.

Once mechanical work was completed, the engineers ganged up on the body and interior. With the help of two-part epoxy, rivets, screening, filler, and a lot of sandpaper, the team was able to force the fiberglass back into shape. The team liked the "rat rod" look of the flat-black primer so much, it decided to carry the look over to the car's final paint scheme.

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Searching on eBay, the team found this bargain-priced snowmobile. It would give up its drivetrain to power the sucker fan.

Next, a rollcage was constructed from scrap pipe and color-matched to the silver turbo piping that stuck out of the hood. A half-inch Lexan barrier shield was also installed between the driver and the sucker system. A full race harness was then added, and a fire extinguisher was mounted within reach of the driver. A main battery-kill switch was wired on the back of the Corvette, and a separate sucker-system kill switch was made for the blower engine and fuel pump.

At the event, the engineers-now going by the moniker "Team Cheaparral"-swept all four categories (Autocross, Concours Judging, Best Engineered, and Top-Finishing Team) and were declared the $2,007 Challenge Overall Champion. (The drag-race portion of the contest was cancelled due to bad weather.) "At the awards banquet, we went up so many times to accept that it was almost embarrassing," says Lockar. "You'll notice I said almost."

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Here's a close-up of the two-stroke, 440cc engine and transmission used to drive the sucker-fan motor.

Its first set of objectives accomplished, Team Cheaparral hope to use the "Sucker Vette" as a way of getting young people interested in engineering careers. Later on, it plans to sell the car and donate the proceeds to the Cincinnati United Way.

Follow along as we show you how Team Cheaparral earned the title of Overall Champion at the Kumho Tires/Grassroots Motorsports $2,007 Challenge.



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