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.
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.
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."
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.