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St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
The valves to open and close the mufflers.
These cars have a vac. source at the engine that goes back to a controller at the rear of the car to open the valves under certain conditions (20%+ throttle and 3000+ RPM) the other side is less muffled and louder than the quiet side.
Last edited by Anthony @ LGMotorsports; 10-21-2014 at 06:25 PM.
Base mufflers have a single outlet that's less than 2 inches in diameter.
NPP mufflers have two outlets 2 1/2" in diameter with one pair open all the time and the other pair opens by opening the flaps at a specific RPM (or whenever you want with an exhaust controller).
10-21-2014, 06:20 PM
