GM drum 2 is a 6-inch x14 inch round carbon fiber repackable muffler with a 2.50-inch or 3-inch free flowing spiral through core wrapped in stainless steel mesh. T304 stainless steel end plate and hardware. 650 auto coated carbon fiber. When part of the copper wire of the low-voltage conductor of the distributor is broken, the cross-sectional area of the conductor is reduced, so as to increase the resistor of the primary circuit and reduce the current in the circuit, resulting in insufficient high voltage generated by the ignition coil. When the engine temperature is low, although it is difficult to start, the engine can run normally after starting. When the engine temperature increases, the ignition coil temperature increases and the resistor increases with the temperature. Therefore, the high voltage generated by the ignition coil will be more insufficient, the high voltage spark will be weaker, and even the fire will break. As the fire is cut off from time to time, the unlighted combustible mixture in the cylinder is discharged into the muffler. When the muffler expands, when the spark in the exhaust gas explodes, it shows that the muffler emits.