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NASCAR announces 2019 rules package

NASCAR officials announced Tuesday two baseline rules packages for the 2019 Monster Energy NASCAR Cup Series season, making a move to bolster competition with enhanced aerodynamic and engine configurations.

The different packages will be tailored to the specific tracks on the Monster Energy Series circuit, with a combination of a smaller tapered spacer to reduce engine horsepower to a target goal of 550 (from 750) and aero ducts to foster tighter racing on a majority of speedways measuring longer than 1 mile. Both features will be in place for 17 of the 36 races next season, excepting the 2019 Daytona 500, which will run with traditional restrictor-plate rules. Five other races will be run with the smaller spacer, but without ducts.

The baseline aero elements of the 2019 rules package are a taller 8-inch by 61-inch rear spoiler, a larger front splitter with a 2-inch overhang, and a wider radiator pan that measures 37 inches wide in the front tapering to 31 inches at the rear. Those base changes will be in place at every race next season with the intent of adding downforce to stabilize handling, a break from a trend of downforce reduction from 2015-18.

2019 Rules

Beyond the baseline components are the smaller tapered spacer (.922-inch versus the current 1.17-inch) and aerodynamic ducts to be used at select oval tracks larger than 1 mile. The smaller spacer will further limit airflow through the engine and thereby horsepower to a figure around 550, down from the current 750.

Five races at larger ovals are exceptions. Both Pocono events and races at Atlanta, Darlington and Homestead will use the smaller tapered spacer, but will not use the aero ducts that transfer air to the side of the car away from the front tires. Neither the smaller spacer nor ducts will be used at short tracks and road courses.

Besides being tested in computer simulations and wind-tunnel time, variations on the new configurations received recent field tests in the 2018 Monster Energy All-Star Race and the NASCAR Xfinity Series on specific speedways. The 2019 package takes cues from those events, which promoted closer competition and increased opportunities for drafting.

Events at Daytona International Speedway and Talladega Superspeedway also will be contested without restrictor plates next season for the first time since 1987. The cumulative effect of the base aerodynamic changes, engine restrictions and aero ducts are expected to keep the speeds and competition close to their current style of racing. The exception is the 2019 Daytona 500, which will be held under the current rules with restrictor plates.

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Rules Package Overview:

Aero Elements

• Spoiler: 8″ x 61″
• Splitter: 2″ overhang, 10.5″ wings at ends of splitter (near tires)
• Radiator pan: 37″ in front tapered to 31″ with vertical fences
• Aero ducts: Used at majority of oval tracks larger than 1 mile

Engine Elements

• 750 HP: 1.17″ tapered spacer (Used at short tracks and road courses)
• 550 HP: 0.922″ tapered spacer (Used at oval tracks larger than 1 mile)


• Enhanced vehicle chassis mandatory at all tracks (previously announced)
• Adding 3 long block engine seals in points races. These are in addition to the 13 short block seals introduced this season.
• 25% reduction in testing (3 organizational tests, down from 4; 3 teams at each Goodyear test, down from 4).