K-tech stealth weird noise

[Captain butters]

I've recently purchased a k-tech stealth exhaust for my 172, but at around 3,000 rpm it is making a weird resonating sound. Any ideas what it is and how to stop it?

 

[Captain butters]

Just to add, this was fitted by a garage who didn't change anything other than the exhaust

 

[Fletcher]

You still have the cat fitted I take it?

 

[Sneak]

Heat shield could have come loose when they fitted it?

 

[Goodj]

Is it a really irritating booming, chavvy noise?

The kind that can be heard 4 or 5 miles away?

Because that's standard with the exhaust

 

[Captain butters]

You still have the cat fitted I take it?

Yes the standard cat is fitted

Heat shield could have come loose when they fitted it?

That is a good shout, thanks

 

[Sneak]

My stealth sounded bloody awful when I fitted a new exhaust mount. Turns out that the shield was resting on top of it

 

[darkbluesheep]

Worth checking Cat to Manifold join as well. They should have noticed this when fitting the exhaust if it has gone but you never know.