i decided to crank her up with no filter or anything on inlet side of turbo.
it set a CEL. ran codes none. so i put all back together (minus the ring) and ran about 100 miles and shut off.
The CEL was because of the Intake Air Temp. Sensor being unhooked from the air filter box when you ran the truck with out the filter box and tube hooked up. It takes it a little while before the ECM reads that it is back on the truck. The silencer ring had nothing to do with the CEL coming on.
I may have given you bad info right there^^^
I didn't read ChaseN sig. I'm ignorant like that. He may be talking about the ring in the inlet duct between turbo & filter. Sorry.