There is some bits of broken catalytic converter which have fallen into my resonator, the cat has been since replaced by the previous owner. Whenever I corner, brake, accelerate, rev the engine, turn the car on or off. I can hear it rattle. Its annoying as people look at my car like there is something wrong with it.

Anyone got any ideas on how to get that metal out? Maybe soapy water will float it out. Or maybe i'd have to take it off and try and shake it out. But I thought i'd ask here first in case anyone has had a similar experience.
I'd like to keep the stock resonator if possible as in one of my previous posts use 'NotAPreppie' suggested it would be better than a cheap ebay one.

Thanks

 

are you sure it's material in the exhaust causing the rattle?
I've seen plenty of cars with aftermarket midpipes / cats, etc where part of the exhaust system is actually vibrating off the cross members and it sounds like a loud rattle.
check your rubber hangers to make sure they're still in good shape as well.

 

Yeah its definitely material in the resonator. Its not the kind of rattle you'd get from the pipe rubbing on something or a rusted heat shield. Its like when you snap the tab off a can of coke and put it inside the can and shake it. Its most certainly bits of catalytic converter in there, the previous owner told me so when I bought it.

 

Pretty sure you'll need to cut it (at the top) and soldier/close the cut back. It happened to me as well, there was no way to shake it or anything to let the piece(s) out (that was soldier residues.. I had no cat by a long time already).

 

^+1
Some resonators also have metal baffles that can corrode and rattle, so It's probably a good idea to remove it and inspect it.

 

Yeah i'll probably take it off tomorrow and see what happens. I have a welder and some old sheet metal. I can probably open it up and check. I'm probably going to end up replacing it one day anyway.

 

Right so I took my car to my mechanic, he was replacing my starter motor with the rounded bolt so whilst it was up on the ramp I just got him to do my exhaust at the same time. And oh boy was that interesting.
So first of all he took off the CAT to put my Decat pipe on. And the CAT was literally empty, it was all gone. Nothing was in there whatsoever. And then he moved onto the muffler which had all that metal rattling around in it.
There was WAY more junk in there than I thought. My CAT had literally disintegrated and huge chunks of it were in the muffler. See images below.
Suffice to say, my car sounds much better now with the Decat pipe and without the rattle. And there is definitely more power.

The junk in my muffer
The empty cat pipe (I know its dark inside but trust me its empty).

 

glad you got it figured out.
I had that happen to an RP supercat while the car was on the dyno! it was hilarious to watch the chunks come flying out through the exhaust.

 

I guess the amount of fuel the RX8 throws into the exhaust really wears on them lol
Glad I don't have one anymore. My mechanic is gonna do the CAT swapsies every year for me at a flat rate of £60. Yearly thats really no problem. I'm gonna get a second hand CAT just to throw on each year.
But I can see why people get decat pipes instead of just gutting their cats, because ive been driving around for quite a few weeks it seems with a self-gutted cat and it doesn't sound nearly as good as the Decat I had put on.
It pops on shifts and gives that true rotary sound. So much nicer. And with the new d585 coils I put on today the car is noticeably faster than it was before. My old coils were buggered, white spots on the bottom of them all.

 

Someone ounce tossed a quarter into my exhaust. Now -that- was annoying. Ending up taking the exhaust off and shaking it to get it out.

 

is that before or after you punched said person in the face?

 

Actually, white spots don't mean anything. There was a TSB about this. You need a timing light to tell the true health of the coils.

 

Well all I know is the new coils run way smoother. I noticed when I was idling that sometimes my rpm's went very juddery before. But now its super smooth. So the old coils were definitely bad. Even the exhaust sound has changed with the new coils, it sounds more rotary now. Before it sounded more dull. Has a much more prominent brap now.

 

When I was working as a mechanic, I removed a Whistler from a customer's tailpipe.
That was funny.

 

This is potentially pretty bad news. The progression is usually as follows:


1. Engine dumps fuel and oil into the cat
2. Cat clogs
3. Cat damages engine
4. Cat breaks up and blows out



Hopefully, you got by without much happening with point 3, but do you know the compression numbers on your rear rotor?

 

I haven't had my 8 compression tested. But i'm not having any common compression issues like trouble with hot starting etc. My engine feels pretty healthy, granted I don't really know what a low compression 8 feels like. But I don't think it has done any damage to the engine.