Originally Posted by Motordyne

Hi Guys,

Just an update - Please allow the ART pipes to have a break in period. ~1500 miles.

The fiberglass packing material is coated with a varnish like substance. A silicagel spray. It helps to keep the fiberglass from floating around during the packing process. Its the same type of fiberglass and coating that is used in mufflers where it goes through a break in period. This coating goes through 3 phases. 1) fresh from the factory where it is semi-rigid. 2) When it is initially exposed to the water vapor in the exhaust gas the silicagel solidifies the fiberglass to a rigid mass and this lasts for about 1000-1500 miles before it begins to soften back up again. 3) After about 1500 miles the fiberglass begins to soften up again and go back to a soft fluffy fiberglass state again. And this is where it reaches its optimum damping charecteristics.

Through the 3 phase changes you will hear a moderate change in the sound. This is normal. After break in the sound will remain constant and attain a smooth deep burbly rumble.