Rattle, what is this rattle? Options

[Euphoria]

Hey, had a rattling problem somewhere in the exhaust recently which I believed was the flex pipe, had it replaced and the noise is still there so I'm fairly sure its the cat, now as far as I can see in the Australian ST204 there is only one cat which is on the manifold? so I looked up on Ebay and they seem the most expensive ones and as for getting them in Australia I'm sure they are super expensive so I have a couple options.

I looked at my friends mums celica recently and noticed it had headers and where my cat was, it looked to have none and the o2 sensor was lower, why is this? would there have been a cat in there that couldn't be seen perhaps?

another option is perhaps gutting the cat until I find one at a wreckers or something, I've heard people say this lowers power and makes it louder, I've also head it makes it no louder and no more or less power, whats really the answer?

thanks, this is driving me crazy.

This post has been edited by Euphoria: Apr 12, 2010 - 11:30 PM

[Galcobar]

And if the only manner in which a hanger could rattle is for the rubber to disappear, you'd have eliminated that as a possible source.

However, as I originally posted:

A hanger might have slipped loose, the rubber connecting the hanger on the exhaust to the hanger on the car might have ripped, or -- as is usually the case -- a weld has broken. As the engine vibrates, you get a rattle.

Note particularly that last point, regarding the welds. The break doesn't have to be big. All that is required -- and all that is usually present -- is a hairline fracture. You actually have to get under the car and inspect each hanger by eye and by hand, at close range. Simply looking under the car to see if the rubber is present is no more effective than deciding your oil pan can't be the source of the leak because you can see the edge of the gasket.