Performance & Hotrod Business - January '15

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54 n Performance & Hotrod Business n January 2015 HOTROD it from a super-comfortable street driver to a track-ready brawler." Regarding basic construction, the primary difference beyond suspension between race or street chassis is material choice. For example, Chestang says lighter drag race chassis are built from 3-by- 2-inch boxed or 1-5/8-inch round tubing and Pro-Touring and Pro Street chassis are built from more rigid 4-by-2-inch material. Builders reaching for higher horsepower and lower weight might use chromoly-type tubing. But whether the chassis is intended for race or street, basic elements of design and fabrication are essential. "Other than perhaps having a roll cage for extra rigidity, or being built with lighter-weight materials for a possible weight savings, they should be the same," says Vandervort. "Both require complete and correct body mounting. Both require a chassis rigid enough for stability; the street version often seeing worse pavement and more miles. Both require a suspension that has sufficient travel and correct no bump steer design in order to deliver all the trac- tion the tires can offer. I reject the idea that a street chassis is less demanding, or that a drag race chassis need not handle properly." Technology has come a long way in solving the problems that plagued the performance pioneers who sought a part- nership between sheer might and delicate control. "Let's face it, a factory chassis in a lot of classic and muscle cars can be downright scary to drive the way the drivetrain wants to be driven," adds Foster. "There would likely be a lot more of them left today if suspension engineers knew then what we know now. Using technology born on the racetrack, our new chassis have had extensive computer-aided geometry design and simulation that allow the suspension components to work rather than fighting each other. The end result is a very smooth system that reacts well to driver input." A Well-Built Chassis All of which points toward a consensus of what defines a well-built chassis. At least in the racing world, safety is the first consideration and is at the top of the list of characteristics that define a well- built chassis. "You have to take it seriously; someone's life is at stake," says Perry. He says Chassis Engineering relies on multi- ple sets of eyes, checking each weld, each dimension and "tag-taping" any spot that is questionable to make sure nothing falls through the cracks. Proper fit to the car is critical, as is the ability to adjust and fine-tune the car to the performance application. It should be free from NVH (Noise, Vibration, Harshness). Foster believes the components that define well-built are strength, well- designed suspension dynamics and ease of installation: "Strength gives it the ability to drive in most any conditions and for a very long life. Suspension dynamics get the chassis to work the way it was intended. Ease of installation—it's gotta fit right without modification or the mainstream hot rodder won't be able to install it." Placement of components like the engine, exhaust and fuel tank should be designed from the beginning into how the chassis is built. Chassis manufacturers Bushing Matters: Good Vibrations Metal scraping metal is the bane of any mechanical device and it's a downright irri- tant when it comes to a vehicle in motion. Walter Chrysler is often credited with designing the first rubber bushings that were used as motor mounts in the 1930s. The idea of isolating the metal com- ponents to reduce vibrations and noise quickly spread throughout the automo- tive industry and was adopted pretty much universally in the years following. The concept has since been perfected, and today, the best quality bushings are made of polyurethane. Energy Suspension's Hyper-Flex polyurethane chassis and suspension compo- nents, for example, have been proven to be more efficient and more durable than rubber bushings and mounts. "From control arm and sway bar bushings to body and drivetrain mounts, poly- urethane components do not wear out or deteriorate from exposure to undercar chemicals and outlast rubber five times longer," says Energy Suspension's Michael Santa Cruz. "Up until the early 1980s, replacement bushings and mounts were only avail- able in various rubber materials for a cost-effective repair part," says Santa Cruz. Using Energy Suspension's own poly materials, the company began making similar bushings and mounts that were soon recognized as being a great improvement and a much more efficient alternative than the stock replacements that had previ- ously been available to OE and aftermarket suspension and chassis upgrades. "Energy's control arm bushings are engineered to be full-floating and non-bind- ing for improved alignment stability and handling," Santa Cruz says. "Higher durom- eter (firmer) bushings result in less deflection and provide an improved contact link between suspension components and the vehicle's chassis." The result is the irritating metal-on-metal vibrations of the past are just that— vibrations of the past. (Photo courtesy Energy Suspension)

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