Hey all! I haven’t posted on these forums before.

 

yup, that sounds like cats to me. i actually have the same sound

 

Its not going to cause damage. Mine rattled for like 5 years and I only just replaced them finally this year.

Options are used OEM cats, New OEM cats (absurdly expensive) or get aftermarket cats / high flow cats. I went with the high flow.

 

That's definitely your cats. Same thing happened to mine and I went with Berk high flow cats... Kinda wish I did test pipes so I could get a flame map but anyway. I picked up a set used for like $250 with minimal mileage. However getting them off is best left for a professional. The top bolts need to be accessed from the engine bay using like 4ft of extensions and the bolts are pretty much always seized on. The shop that did mine pulled my wheels and wheel well, the undertray and then cut the original studs off, drilled them out and installed new ones with the new high flow cats. They've done it quite a lot so they were able to do it relatively quick, it was a few hundred to install them. After seeing the install, paying the money is definitely worth it. I went to two mom and pop shops with a good reputation and they both turned me away after seeing the bolts. Dealer cost is going to be astronomical. It shouldn't do any damage, the noise drove me nuts so I replaced mine promptly. It could lead to ****ty MPG and a CEL if pieces are breaking apart and clogging the cats however.

 

That sounds like the heat shields on the cats, it should cost you between nothing and $5.00 to fix... its a very common problem with these cars (there are posts all over this site going back probably a decade on the issue)... they rot and start to rattle (most likely because of he heat cycles and the dissimilar metals in contact), sometimes you can just bend them back an inch or two where they are rotted or cut them off with tin snips, others have used hose clamps to tighten them down to the body of the cat...if you hear a noise after you cut them off it may be the catalyst inside has come apart, that that is less likely unless you've had an impact and it doesn't sound like that in the clip

 

Agreed. Start there before you pursue big money in replacement parts & labor.

I've never had a car where the heat shields don't eventually break through their connection points and start rattling. Every single car ever. In fact, my kid's Sentra is experiencing that exact same thing right now, where the heat shield if just kind of hanging there.

Well, not the G, because I replaced the cats as an upgrade when there was only 17k miles on the car, but still...

 

I just had to replace my drivers catalytic converter costed me $900 for the cat and install.

 

This is exactly what my catalytic converter sounded like. I removed it yesterday and the aft mesh was intact (not melted / damaged) on the driver's side converter but was able to slide fore / aft in the shell causing the rattling. Fixed it. Now my passenger side is rattling but to a lesser degree than the driver's side. Before I replace that one I am going to try to deform the shell of the converter to pinch down the mesh.

 

How did you fix the internal rattling on the other one?

 

Fixed by new catalytic converter so not so much a fix but a replacement. Went with one from Rock Auto. $250 shipped. Bolted right up no problem. Even had the bracket for the mount. If you're going to replace by yourself be ready to face the demon bolt. Not fun.

Going to try to deform my passenger side aft cat this weekend to see if I can pinch down on the matrix without breaking it. Will let you know how it goes. I think I'm going to use a clamp.

Brian

 

I have Berk HFCs on mine, the tuning shop that installed them (last august) cut the old bolts off to get the cats out and put new hardware on with the new ones, I'm hoping they won't be as much of a pain to get off if it is my cats making this stupid noise. I really don't want to pay $300+ to replace them once again in under a year...

 

I just had mine replace and Top Speed Resonated Test PIpes and what do you know I had to change the whole thing from the y pipe to the muffler in the back because it had a hole in it, they quoted me $2500 to replace all. so I went on the internet and found a guy in toronto with one that came from a g37 really nice one, he was asking 220 for it so I drove to toronto and had it install for me for $150 and it work like a charm no noise. so it was a 4h trip well worth had time to chill with my sister too lol. save em a lot of money too. I went to kenny u pull and saw a muffler on a m45 and it was brand new so I may try to scoop that one for later in time lol

 

My Berks HFCs are very loud and droney (no rasp though, so i guess I've got that going for me). I've had them on the Invidia Q300 exhaust and the stock one. The guy who sold them to me said they were too loud and he's was getting FI RHFCs. I thought having them on the Q300 would be tolerable, but I think it's still obnoxiously loud. If I had it to do over again, I'd skip Berks and go right to the FI. I live on a mountain, so I'm in the drone-zone RPM wise from the time I turn off the highway until home. I may just be more sensitive to it than others, but I wouldn't recommend the Berks to anyone that cares what their neighbors think. What's your experience with them, NLE?

 

I'm a really loud person and do everything as loud as possible so it doesn't phase me much especially in relation to how loud my stereo is half the time lol. The noise I was complaining about earlier turned out to be an issue with my tune that was resolved with flashing a new map, my motor actually had spark knock. So in that case my experience with their product hasn't been bad for the most part. I can totally see how these HFC's would **** someone else, I just cant imagine how much the sound could really differ across all HFCs? Most of the guys I roll with run test pipes and I can barely hear my car over theirs so I may not be the best person to ask due to experience hahaha.

 

Didn't see anyone suggest, since you're under 80k, I'd look into the federal law for cats. I'm pretty sure if it's under 80k they're covered by federal warranty.