ChuckT
05-06-2010, 12:01 PM
In case you're coming out to watch this weekend, and haven't been to a Pro Am, or seen throttle stop racing before, here is a brief explanation of the classes.
HOT ROD
7.00 index (10.90 quarter mile), open to door cars only. As in all throttle stop classes, you'll often see the cars launch, slow down as the throttle stop kicks in, and take off again when the car comes off of the throttle stop. The throttle stop is hardware on the car that does just as its name implies, taking the car from wide open throttle to a high idle, with the time set according to each racer's set up, then allowing wide open throttle again. In Hot Rod, you see many classic musclecars of all eras. The cars leave on a .500 pro tree, and breakout if they run quicker than the 7.00 index. If both drivers break out, the one that did so by the least amount wins.
SUPER ROD
6.40 index (9.90 quarter mile), open to door cars and roadsters. The cars leave on a .400 pro tree, with the same rules applying as in Hot Rod.
QUICK ROD
5.70 index (8.90 quarter mile), open to door cars, roadsters, altereds, and dragsters, this is the quickest throttle stop class. This class is also on a .400 pro tree, with break out rules applying.
STOCK
All cars in this class demand original production equipment with which the car was marketed to the public. Cars run on a handicapped start (bracket style), but each must run under their sub-category’s National Index, determined by a power to weight ratio. If 2 cars with the same class designation are paired up, it will then be a heads up race, with no breakout. Tire size is limited to 30" tall by 9" wide, with footbrake launch only.
SUPER STOCK
As the arena for factory muscle car showdowns for decades, this class spotlights some of the most powerful production vehicles ever built. Cars run on a handicapped start, but each must run under their sub-category’s National Index, determined by a power to weight ratio. In addition to traditional Super Stockers, there are also sub-categories for GT entries, front wheel drive conversions, trucks, and Super Stock production entries. As in Stock, if 2 cars with the same class designation are paired up, it's a heads up, no breakout, first to the finish wins, race. Tire size is unlimited, and you will see many wheelstands, as weight transfer is extremely important in this class. Footbrake or transbrake launches are allowed, but not the use of a delay box.
TOP DRAGSTER
The fastest sportsman category in drag racing, Top Dragster is also renowned as one of the most innovative classes in IHRA. Combining dragsters and altered vintage roadsters, it is bracket racing, using a .500 full tree, and delay boxes are allowed. Copious amounts of nitrous oxide are often used to generate power. In the Divisional races, all run, but must be quicker than 5.00 in the 1/8th.
TOP SPORTSMAN
As the class that spawned Pro Modified, Top Sportsman remains the “baddest” sportsman class on the planet. Covering the spectrum of passenger car body styles and power plants, Top Sportsman racers are not encumbered by displacement limitations or customizing rules, offering some of the most radical visual and mechanical thrills in drag racing. This is also a bracket class, and you will often see long purges of nitrous over the windshield after the burnouts and as the cars stage. Uses a full .500 tree, and delay boxes are allowed.
HOT ROD
7.00 index (10.90 quarter mile), open to door cars only. As in all throttle stop classes, you'll often see the cars launch, slow down as the throttle stop kicks in, and take off again when the car comes off of the throttle stop. The throttle stop is hardware on the car that does just as its name implies, taking the car from wide open throttle to a high idle, with the time set according to each racer's set up, then allowing wide open throttle again. In Hot Rod, you see many classic musclecars of all eras. The cars leave on a .500 pro tree, and breakout if they run quicker than the 7.00 index. If both drivers break out, the one that did so by the least amount wins.
SUPER ROD
6.40 index (9.90 quarter mile), open to door cars and roadsters. The cars leave on a .400 pro tree, with the same rules applying as in Hot Rod.
QUICK ROD
5.70 index (8.90 quarter mile), open to door cars, roadsters, altereds, and dragsters, this is the quickest throttle stop class. This class is also on a .400 pro tree, with break out rules applying.
STOCK
All cars in this class demand original production equipment with which the car was marketed to the public. Cars run on a handicapped start (bracket style), but each must run under their sub-category’s National Index, determined by a power to weight ratio. If 2 cars with the same class designation are paired up, it will then be a heads up race, with no breakout. Tire size is limited to 30" tall by 9" wide, with footbrake launch only.
SUPER STOCK
As the arena for factory muscle car showdowns for decades, this class spotlights some of the most powerful production vehicles ever built. Cars run on a handicapped start, but each must run under their sub-category’s National Index, determined by a power to weight ratio. In addition to traditional Super Stockers, there are also sub-categories for GT entries, front wheel drive conversions, trucks, and Super Stock production entries. As in Stock, if 2 cars with the same class designation are paired up, it's a heads up, no breakout, first to the finish wins, race. Tire size is unlimited, and you will see many wheelstands, as weight transfer is extremely important in this class. Footbrake or transbrake launches are allowed, but not the use of a delay box.
TOP DRAGSTER
The fastest sportsman category in drag racing, Top Dragster is also renowned as one of the most innovative classes in IHRA. Combining dragsters and altered vintage roadsters, it is bracket racing, using a .500 full tree, and delay boxes are allowed. Copious amounts of nitrous oxide are often used to generate power. In the Divisional races, all run, but must be quicker than 5.00 in the 1/8th.
TOP SPORTSMAN
As the class that spawned Pro Modified, Top Sportsman remains the “baddest” sportsman class on the planet. Covering the spectrum of passenger car body styles and power plants, Top Sportsman racers are not encumbered by displacement limitations or customizing rules, offering some of the most radical visual and mechanical thrills in drag racing. This is also a bracket class, and you will often see long purges of nitrous over the windshield after the burnouts and as the cars stage. Uses a full .500 tree, and delay boxes are allowed.