Exhaust noise when hot.

[con1981]

Hello fellas having a strange one with my 172. As the car gets hotter the exhaust gets louder & raspier to the point where I presumed there must be a leak or a blow in the system. I've been under the car from front to back and there is no leak I can find. It seems to be coming from either the centre section or the cat. The rear box was recently changed and the centre is about 2 years old. The cat looks in good condition and I have no emissions light on. Any ideas what could be causing this?

 

[imprezaworks]

What exhaust

 

[con1981]

It's a standard system from Ecp, klarius I believe

 

[imprezaworks]

They arnt the most long lasting exhausts I'm my experience, well on other cars anyway.

 

[con1981]

New centre section then. Like I say it sounds like a blow but there isn't one which leads me to believe it's the baffles

 

[imprezaworks]

We had a similar ish problem with a customer car. Got worse when hot, made a hell of a noise. It was the exhaust at fault.

 

[con1981]

Well been back under it tonight and these a slight blow on the centre pipe. I've gun gummed it but this has made lite difference. I've replaced the rear poly flex bush from the rear mount for a standard one as I wondered whether it was down to the exhaust vibrating. A little quieter but not by much.

I'll replace the centre section at the week end hopefully this will sort. Back box is only a few months old do I doubt it's this. Either way I have the receipt so if it does turn out to be the back box I should get an exchange

 

[leedsboy]

I've got the same kind of problem but with a Piper exhaust. It's fine up until around 2.5k revs but as soon as you properly put your foot down, it sounds really raspy and 'not right'.

How did you test to see whether yours was blowing or not?

 

[imprezaworks]

Stick your hand over the backbox when the car is idling.

 

[con1981]

Well it did turn out to be a bad centre section. My bodge repair of heat proof tape and gun gum didn't hold. As you can see from the pics it had blown a full corner of my bodge away.

New klarius centre now fitted. I have to say these are the worst fitting exhausts I have ever experienced I now have a slight back box on show having spent hours trying to get it straight.

This was the best I could get it