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]

Given he's in Australia, I doubt he was seeing much in the way of California Celicas.

Your Celica appears to be equipped with a 5SFE, which had its primary cat directly under the log-style manifold (single-piece extractor). It effectively acted as the manifold's collector.

Your friend's mom's Celica might be another model, or have received an engine replacement from a Camry. The 5SFE in the Camry received a manifold with separated runners (4-1 or 4-2-1 extractor design). This places the catalytic converter much lower in the exhaust setup.

However, I'd guess that the rattle you're hearing isn't coming from inside your catalytic converter. Rattles from the exhaust are typically due to the hangers. 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.

Easy test: set the car up on a lift and do what you have to in order to get the rattle to sound (I had to pull the emergency brake and put the car into reverse). Then grab the exhaust (I suggest a heavy glove). Then it's just a matter of finding which hanger is rattling. I managed this without putting the car on a lift, but I'm slender enough to reach the exhaust while the car's on the ground.