Exhaust making weird sounds

[ADubs07]

So i installed new headers into my integra the other day.. They were OBX 4-2-1 headers and despite the fact they didnt give me the sound i was looking for, they also caused me more problems. When i slowly accelerate and sometimes when the car is idling, i can hear a slight rattling/scraping sound. Sounds like loose pieces of metal clanging against each other. I checked underneath for any loose bolts or heatshields but everything seemed fine. It sounds like the rattling/scraping was coming from my cat converter so i might have to get that replaced..
I also think i have a leak somewhere in my exhaust and i cant exactly pin point where it is. When i accelerate hard i can hear this sort of weird wind-like sound.. but it sounds like something is spinning really fast.

Can anyone help me out? I am more concerned with the leakage i may possibly have.. Thanks

[Lomac]

This isn't the safest way to check for leaks, but jack up your car (make sure it's safely secured!!) and crawl underneath while the engine is running. Get a friend to tap the throttle from the engine bay. As he does that, try to listen for where the leak may be coming from. Look specifically where the DP meets the Cat and also where it's bolted to the engine (or exhaust logs, if the design uses part of the stock header). If it's leaking from one of those two points (which isn't impossible for aftermarket headers, even OBX), try using a different gasket (metal vs paper/cardboard) or put in some muffler cement.

As for the rattle, mine does the same thing at certain RPMs. I've no loose bolts or bits touching the frame/floor; rather, it managed to change the sound of my Flowmaster system, giving it a very distinct rattle sound between 3000 and 5000 RPMs. Could be the same situation for you. And as you mentioned, it could be that the Cat is simply dying inside by now.

[ADubs07]

thanks for the reply
i got it checked out today..
my cat was dying, but i replaced it with just a test pipe for now
and as for the leak, there is crack in the header where the pipes join up.. its quite expensive to fix (more than what i got the headers for) so i might just buy new ones instead!

[!SG]

1) check gasket, and if possible, get new ones. i think even lordco carries new gaskets.

2) check if the header is rubbing against anything or even ur exhaust because the new header may be pushing the exhaust piping a bit towards something.

3) look for faulty header, it happens =/

oh nevermind, read ur reply.