NASCAR has confiscated parts from the Joe Gibbs Toyota that carried Denny Hamlin to third in last weekend's Brickyard 400 at Indianapolis to investigate a possible technical breach.
Series spokesperson Kerry Tharp told NASCAR.com that there were "possible issues with several rear firewall block-off plates" on Hamlin's Camry.
The plates are designed to serve as a driver protection device by shielding them from fluids or fumes, however if they become detached during the race they can potentially increase downforce by influencing the airflow from inside the car.
Rule 20-3.4.5 of the NASCAR regulations states:
"Block-off plates/covers used in rear firewalls in place of blowers, oil coolers, etc, must be constructed of 22 gage (0.031 inch thick) magnetic sheet steel. Block-off plates/covers must be installed with positive fasteners and sealed to prevent air leakage.
"Carbon fibre or aluminum block-off plates/covers will not be permitted."
The parts will be inspected at NASCAR's Research & Development Centre in Concord, North Carolina before the series decides what, if any, action will be taken.
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