S.C. Code Ann. § 56-5-5020

Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise and annoying smoke and no person shall use a muffler cutout, bypass or similar device upon a motor vehicle upon a highway. The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes and smoke.