bizarre exhaust noise when hot
 

I have an STI Sports Muffler (full stainless the one with a 120mm tip, not the smaller one fitted standard to some jap spec classics) and when the car gets hot, it starts making clonking/pinging sounds (driivng, idling) and even when turning the engine off it makes a sound like hitting a small hammer against a little bell. When the engine is off it's the most audible and goes on for about 5 minutes until it cools down.
The backbox sound repeats itself in like 5 second intervals. you hear the normal clicking sound from the engine when turned off & cooling down it's like click click click..PINGGGG click click clikc PINGGGG (errr do you get it??)

What could this be? When re-fitting the standard twin "pea-shooter" it dissappears. Would there be an easy fix to stop the backbox from making this pinging/clonking sounds? Did anybody experience this with another backbox make? I was thinking of contacting STI directly but I cannot find any contact details anywhere.
Any advice appreciated!!

Ramon

Just sounds like the exhaust material cooling down, as there is perhaps less muffling in the Sti box & different insides than your standard, You can here it more pronouned, I would not worry

Dean

Thanks Dean for the reply. Actually I am not too worried as I was guessing that it has something to do with the heat flow thru the backbox having less complex interior structure etc.
I was just thinking if there would be an easy way to reduce the noise as it is quite audible, even when standing like 20 metres from the car you can still hear it go "ping.........................ping................ ...........ping".
Again, not worried about something broke it's more the comments I keep getting on my workplace's parking "What a funny noise" or "Your exhaust seems broken" etc....

Would fitting a small steel belt behind the muffler help? I was just thinking since it sounds like hitting a spoon against a bell it makes sound but if you would touch the bell the sound stops. Thus, eventualy the steel belt wrapped around the pipe (under the car of course so that it would bot be visible) could eventually stop the sound from being too audible? Stupid idea?
Ramon

The belt idea may work, But it will propably just emmit from the tail pipe, You could always tell them that it is a new sonar proximity detector as developed by the Navy :D or plug the box with a large spud :D :D

Dean

I prefer the belt idea. I've already came up with all kinds of silly comments concerning the Turbo Timer and the car idling while I walk away from it.

"Hey, you don't turn off your car" while they stand next to it with a puzzled face.

I then usually act like I don't have no clue what's going on and act like there's something wrong with the car....