New Exhaust "DING"

simul8r

3 weeks ago I had the Nismo R-Tune exhaust installed, and I know that metal expands when hot; however, there is a loud "ding" that happens about every 15-20 seconds after the exhaust is hot. The ding can only be heard while at idle or when stopped, not while driving.

I'm just wondering if other aftermarket CBE units do the same thing, and also if the noise eventually goes away or just fades to a not-as-noticeable level after the system is more seasoned.

I've had the exhaust inspected by the shop that did the install and everything is copacetic, but it's a tad annoying when your car sounds like a ticking bomb in the parking lot of Lowe's.