Heads-up racing can be a brutal ego-busting venture. There's no room for second best, and only the first person across the stripe gets the win, the "big" money, and the bragging rights. While it's important to have big horsepower to propel your bullet down the quarter-mile, many secrets lie within the first 60 feet. If you're running at the local track on grudge night, you can use the fattest, stickiest tires you can fit under your car for maximum traction, but in most heads-up classes, the rules are intended to make the tire a limiting factor. The NMCA's BFGoodrich Traction Advantage (TA) class is a case in point-racers have to run on a radial tire.
To get a closer look at the Super Series TA radial racers and to learn more about the delicate balance between power and adhesion, we flew East to National Trail Raceway in Columbus, Ohio, for the NMCA/ NSCA Super Series Finals on the weekend of September 27, 2002.After setting up our base camp in the TA pits, we strapped on the trusty Nikon and slithered around to explore every nook and cranny of all the radial-tired rides.
Unlike other classes that limit camshafts, power adders, or cubic inches, TA rules are relatively liberal, allowing competitors to arm themselves with seriously stout powerplants. The biggest restriction is a ban on exotic raised-runner or altered-valvetrain cylinder heads. Otherwise virtually unlimited modifications are allowed. There's no limit on the cubic inches you can stuff in the engine bay, and you have several choices when it comes to power adders. You can run a single-stage nitrous plate or fogger system, use any supercharger with a maximum 5.5-inch inlet diameter (potential for 1,400-plus horsepower), or run a single turbocharger with a maximum 101mm-inducer-wheel diameter.The weight requirements are also extremely forgiving, with small-block entries weighing in at a minimum 3,050 pounds and big-blocks at a slightly heftier 3,450 pounds. The chassis rules mandate stock-style suspension with no tubbing and allow any radial-design tire with a maximum 325mm sidewall designation, as long as they do not protrude outside of the exterior body lines. And each car must retain its original appearance and profiles; that means you won't see any sheetmetal wings.
Every TA racer has a different opinion about how to launch a radial-tired car, and we ultimately learned that it takes seat time and experimentation to make them work. But when they do, the big boys get those rollers reaching for the sky.
DiversityThe BFGoodrich Traction Advantage (TA) class attracts a diverse combination of motors. Some like 'em big, while others take advantage of the 400-pound weight break given to small-blocks. One isn't necessarily better than another, but the rule does a great job of bringing in cars that may otherwise not fit into any particular class. Either way, it's a tremendous challenge to launch these big-power cars on DOT-approved radials, and that's ultimately the greatest equalizer. Power helps on the big end, but TA is without a doubt a suspension-tuning and driver's class.
Digi-What?There's one Traction Advantage secret we had to divulge. While drag radials do an exceptional job of biting the track, just about every TA car was outfitted with a nitrous-delay timer, such as N.O.S.'s Digi-Set, and a multistep ignition retard.
On a nitrous car, the delay timer allows the driver to launch on the motor only, delaying the nitrous activation until he wants it to come on (anywhere from a tenth of a second or more into the pass ). Once the preset time has elapsed, the timer powers up the nitrous system and reduces the total ignition timing with a multistep digital retard.
For example, a car may launch on the motor with 30 degrees of total timing and delay the nitrous for half a second. Once that half-second has elapsed, the timer simultaneously triggers both the nitrous and the multistep retard, with the multistep retarding the timing to the level of a safe nitrous tune-up. In operation, the timer is wired to a wide-open-throttle switch on the carburetor or into the transbrake. Timers like these range in price from as low as $20 to $100 for the fancier units.