Theres this metal expanding noise coming from my resonator. It only happens when my car is warmed up and it persists for roughly 5-10 min after my car is turned off. Any suggestions as to what this can be? Or has anyone had a similar problem?

 

are you sure its you're resonator and not a header bracket or heatshielding hitting your pipe?

I had a similar problem and it was the header bracket on my Mugen header

 

I'm running my stock header. I jacked up the car and looked all over. The resonator and piping are not rubbing against anything. wheres the header bracket located?

 

it might just be the metal cooling off at a rapid rate.