IR supressors

I was about to pot it on the Bronco thread, but since this topic is a bit more general, I’m opening a new thread about IR suppression measures on turbofans, diagrams and schematics about helicopter systems would be interesting as well, but I’m more interested on systems installed on turboprops or aircraft turbofans, there is one supposed example on the C-130, i think is the COIN version, but i find hard to believe these ‘suppressors’ are something more than simple covers to force the air flow over the exhaust.