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You'll notice horsepower discrepancies among different series' 358-cubic-inch V-8s.

By Robert J. Gottlieb |   |  
With the addition of its new SuperTruck Series, NASCAR now has a dozen touring series, ranging from Winston Cup to the little-known Goody's Dash, and rules for each vary widely. NASCAR is fairly secretive about its rulebook-you have to purchase a membership (costing as much as $500, depending on the series) to get a copy-but we got our hands on the regs for nine of the group's series. A big change for '95 is the Busch Series' phase-in of low-compression-ratio, small-carburetor V-8s. You'll notice horsepower discrepancies among different series' 358-cubic-inch V-8s; those are due to varying carburetor sizes, restrictor plates, and compression ratios. Here's a quick look at the major variables of nine of NASCAR's touring series.A couple years ago, virtually every Top Fuel dragster was equipped with tiny, 5.0-inch-diameter front wheels. Today, all leading Top Fuel teams have abandoned the little ones for 17-inchers. Former drag-racing champion Frank Hawley, who now runs The Drag Racing School, was instrumental in the movement toward bigger wheels. When he was racing Top Fuel, Hawley observed that little front wheels allowed the stage beam to close 0.03 second sooner than the 17-inchers, and that this sliver of time was, in effect, added to the car's elapsed time. "When I was driving [Darrell] Gwynn's [Top Fuel] car, we were the No. 1 qualifier six times, but five times we were No. 2, each by less than 0.03 second," said Hawley. "It pays $4000 to be the top qualifier; nothing to be second. We'd have won an additional $20,000 just by installing the big wheels." Other advantages of better elapsed times: lane choice during eliminations, qualifying position (or for some, even qualification at all), and the chance to break records, and thus, get your sponsors' name mentioned. Here's how it works: Imagine we've welded two cars together side-by-side and drive them as one. The leading edges of the tires are exactly lined up. Both break the stage beam at exactly the same instant, but the trailing edges of the larger wheels block the light 0.03 second longer. Both arrive at the finish line at the same moment, but the driver of the small-wheeled car gets credit for a 0.03-second better reaction time, while the driver of the big-wheeled car earns a 0.03-second better elapsed time (i.e., little wheels, 4.850 e.t., with a 0.415 r.t.; big wheels, 4.820 e.t., with a 0.445 r.t.). The time from when the Christmas tree's yellow lights illuminates to the moment the finish line is crossed is exactly the same (5.265 seconds), but the big wheels shift time from where it hurts to where it doesn't matter (unless you're a driver whose job security depends on good r.t.'s). The big wheels also offer more staging positioning options and slightly reduce the possibility of red-lighting. (Drag racing primer: Reaction time is the time between when the yellow lights illuminate and the car leaves the stage beam. Elapsed time is the time between leaving the stage beam and crossing the finish line.) The small wheels were pioneered several years ago when Don Garlits installed airplane tires on his car in an aggressive effort to reduce aerodynamic drag, but Hawley has seen no tests indicating that any aero-advantages exist. A smaller wheel weighs about 9 pounds less than a larger one, but that plus is negated because many teams must add far more than the difference in ballast in the nose to prevent wheelstands and blow-overs. Meanwhile, the larger wheels have a gyroscopic effect that may slightly increase straight-line stability, much as would increasing caster angle.
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