Hi all,

My trusty 2009 G37x has 150k miles. It's essentially perfect mechanically (and quite nice cosmetically) aside from a rattling catalytic converter, especially after a couple of recent repairs.

I'd replace both with something close to stock and aftermarket if I could, but I'm in California so need CARB compliant. Are there any legit solutions other than spending $1100 each at the dealer? That's just a total nonstarter given the age and value of the car, especially since the rattling CATS are not triggering CEL's or causing performance issues. It's also only noticeable at idle.

Are there any other solutions out there? Used? Getting the loose pieces out?

 

There is a bunch of oem replica cats on eBay for a few hundo. Most of these are made in Canada. I suspect they will do just fine. I considered getting some myself.

 

My Cats were both rattling, and it was coming from inside the cats themselves. Mechanic cut them open and found the ceramic blocks sliding back n forth inside both of them.
From this point you can replace them right there and then, or you can gut them. Gutting them keeps the cats on your car minus the ceramic. Cheaper to gut them and look for alternatives down the road. In the meantime, no rattle, performance increase and increased noise.

If you keep the hollow cats on your G, the appearance of cats remain, with no annoying rattle and/or decreased performance!