I have had the set up of the Crawford Cats. & the Nismo cat-back exhaust & Nismo exhaust headers for about 6 months to year now. I have just started to get this annoying metal on metal rattle that is absolutely driving me nuts!!
I did a search & saw plenty of threads with the rattle issue after initial install but not after months of having them installed. I took off the stock heat shields thinking the exhaust might have shifted & was hitting those. Nope, still have that rattle. It is pretty loud as well. It is mainly from the drivers side from what it sounds like. How long do these cats usually last? I was thinking maybe it was a lose bolt or something any other suggestions on where this rattle might be coming from? The only other info I can offer is that it started out intermittent & now is pretty constant & is proportionate to the rpm. Thanks

 

Catalytic converters last the life of the car.

Whatever is loose is not going to get better, its just going to get more loose. You have had the car on a lift and checked all the blots? Under acceleration the engine twists and so does everything attached to it. So clearance in a static condition (engine at idle) can be deceiving.

 

No I have not & that was the only other thing I could think of was the bolts where lose. I am going to have to get it up in the air or perhaps at the dealer when I go in for a 4 wheel alignment. Thanks for the tip!! =)

 

Maybe Crawford cats & Nismo exhaust is such a bad marriage combo.

 

I think crawford uses carsound/magnaflow HFC in their setup. I have had history with them in using them with previous vehicles. What I think has happened is a section of the 'guts' has broken free and is causing the rattle. Luckily, it is most likely only a section of the inards. I have seen this numerous times in using carsound HFCs.

I would suggest taking them off and trying to determine which end has the loose section, the in or out end and then taking a large drill bit and break up the loose section and remove it. I, as recently as a month ago, did this on one of my cars HFCs. The HFC had 3 sections of material inside and one of those sections had broken free. I broke up the loose section and removed the pieces and reinstalled it.

good luck

 

As far as the Nismo & the Crawford together it has been more of a pipe issue not a bolt or inner "guts" issue. I think Crawford did a good job resloving that pipe issue they had from the new design that I bought.

Yes, the rattle is annoying & I think the 2 guys did a good job of suggesting what it might be because that is all I could think of. I was just hoping that it was not that piece "guts" inside the Cat.

Thanks, for the suggestion about the drill. That is something that I have not heard of doing before. There is no CEL code that pops up after that is there?

Thanks guys you have been a big help.

 

What genius told you that?????

Stop spreading rumors!

 

LOL.

 

look at the welds on your y-pipe, mine started to make this metal on metal slapping sound comming from the passenger side and i noticed the welds on the nismo y-pipe had cracked allowing the 2 sections of y-pipe to slapp together at around 2500-3000 rpm (point of most resonation in my car).

 

The Crawford Cats are cracked at the "U bracket" so I am pretty sure that is where the rattle is comming from. I can knock on it with my hand & hear the rattle.....I wonder if it is under warrenty...

I have had the Y-Pipe issue as well.